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/* LLVM LOCAL begin (ENTIRE FILE!) */
/* Tree type to LLVM type converter
Copyright (C) 2005, 2006, 2007 Free Software Foundation, Inc.
Contributed by Chris Lattner (sabre@nondot.org)
This file is part of GCC.
GCC is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
Software Foundation; either version 2, or (at your option) any later
version.
GCC is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
for more details.
You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING. If not, write to the Free
Software Foundation, 59 Temple Place - Suite 330, Boston, MA
02111-1307, USA. */
//===----------------------------------------------------------------------===//
// This is the code that converts GCC tree types into LLVM types.
//===----------------------------------------------------------------------===//
#include "llvm-internal.h"
#include "llvm/Support/Host.h"
#include "llvm/CallingConv.h"
#include "llvm/Constants.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Module.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Assembly/Writer.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/Support/raw_ostream.h"
#include <map>
extern "C" {
#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tree.h"
}
#include "llvm-abi.h"
//===----------------------------------------------------------------------===//
// Matching LLVM types with GCC trees
//===----------------------------------------------------------------------===//
//
// LTypes is a vector of LLVM types. GCC tree nodes keep track of LLVM types
// using this vector's index. It is easier to save and restore the index than
// the LLVM type pointer while usig PCH. STL vector does not provide fast
// searching mechanism which is required to remove LLVM Type entry when type is
// refined and replaced by another LLVM Type. This is achieved by maintaining
// a map.
// Collection of LLVM Types
static std::vector<Type *> LTypes;
typedef DenseMap<Type *, unsigned> LTypesMapTy;
static LTypesMapTy LTypesMap;
static LLVMContext &Context = getGlobalContext();
// GET_TYPE_LLVM/SET_TYPE_LLVM - Associate an LLVM type with each TREE type.
// These are lazily computed by ConvertType.
#define SET_TYPE_SYMTAB_LLVM(NODE, index) \
(TYPE_CHECK (NODE)->type.symtab.llvm = index)
// Note down LLVM type for GCC tree node.
static Type * llvm_set_type(tree Tr, Type *Ty) {
#ifndef NDEBUG
// For x86 long double, llvm records the size of the data (80) while
// gcc's TYPE_SIZE including alignment padding. getTypeAllocSizeInBits
// is used to compensate for this.
if (TYPE_SIZE(Tr) && Ty->isSized() && isInt64(TYPE_SIZE(Tr), true) &&
(!isa<StructType>(Ty) || !cast<StructType>(Ty)->isOpaque())) {
uint64_t LLVMSize = getTargetData().getTypeAllocSizeInBits(Ty);
if (getInt64(TYPE_SIZE(Tr), true) != LLVMSize) {
errs() << "GCC: ";
debug_tree(Tr);
errs() << "LLVM: ";
Ty->print(errs());
errs() << " (" << LLVMSize << " bits)\n";
errs() << "LLVM type size doesn't match GCC type size!";
abort();
}
}
#endif
unsigned &TypeSlot = LTypesMap[Ty];
if (TypeSlot) {
// Already in map.
SET_TYPE_SYMTAB_LLVM(Tr, TypeSlot);
return Ty;
}
unsigned Index = LTypes.size() + 1;
LTypes.push_back(Ty);
SET_TYPE_SYMTAB_LLVM(Tr, Index);
LTypesMap[Ty] = Index;
return Ty;
}
#define SET_TYPE_LLVM(NODE, TYPE) llvm_set_type(NODE, TYPE)
// Get LLVM Type for the GCC tree node based on LTypes vector index.
// When GCC tree node is initialized, it has 0 as the index value. This is
// why all recorded indexes are offset by 1.
extern "C" Type *llvm_get_type(unsigned Index) {
if (Index == 0)
return NULL;
assert ((Index - 1) < LTypes.size() && "Invalid LLVM Type index");
return LTypes[Index - 1];
}
#define GET_TYPE_LLVM(NODE) \
llvm_get_type( TYPE_CHECK (NODE)->type.symtab.llvm)
// Erase type from LTypes vector
static void llvmEraseLType(Type *Ty) {
LTypesMapTy::iterator I = LTypesMap.find(Ty);
if (I != LTypesMap.end()) {
// It is OK to clear this entry instead of removing this entry
// to avoid re-indexing of other entries.
LTypes[LTypesMap[Ty] - 1] = NULL;
LTypesMap.erase(I);
}
}
// Read LLVM Types string table
void readLLVMTypesStringTable() {
GlobalValue *V = TheModule->getNamedGlobal("llvm.pch.types");
if (!V)
return;
StructType *STy = cast<StructType>(V->getType()->getElementType());
for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i)
if (const PointerType *PTy = dyn_cast<PointerType>(STy->getElementType(i)))
LTypes.push_back(PTy->getElementType());
else
LTypes.push_back(Type::getVoidTy(Context));
// Now, llvm.pch.types value is not required so remove it from the symbol
// table.
V->eraseFromParent();
}
// GCC tree's uses LTypes vector's index to reach LLVM types.
// Create a global variable with struct type that contains each of these.
void writeLLVMTypesStringTable() {
if (LTypes.empty())
return;
// Convert the LTypes list to a list of pointers.
std::vector<Type*> PTys;
for (unsigned i = 0, e = LTypes.size(); i != e; ++i) {
// Cannot form pointer to void. Use i8 as a sentinel.
if (LTypes[i]->isVoidTy())
PTys.push_back(Type::getInt8Ty(Context));
else
PTys.push_back(LTypes[i]->getPointerTo());
}
// Create variable to hold this string table.
(void)new GlobalVariable(*TheModule, StructType::get(Context, PTys), true,
GlobalValue::ExternalLinkage,
/*noinit*/0, "llvm.pch.types");
}
//===----------------------------------------------------------------------===//
// Type Conversion Utilities
//===----------------------------------------------------------------------===//
// isPassedByInvisibleReference - Return true if an argument of the specified
// type should be passed in by invisible reference.
//
bool isPassedByInvisibleReference(tree Type) {
// Don't crash in this case.
if (Type == error_mark_node)
return false;
// FIXME: Search for TREE_ADDRESSABLE in calls.c, and see if there are other
// cases that make arguments automatically passed in by reference.
return TREE_ADDRESSABLE(Type) || TYPE_SIZE(Type) == 0 ||
TREE_CODE(TYPE_SIZE(Type)) != INTEGER_CST;
}
/// GetTypeName - Return a fully qualified (with namespace prefixes) name for
/// the specified type.
static std::string GetTypeName(const char *Prefix, tree type) {
const char *Name = "anon";
if (TYPE_NAME(type)) {
if (TREE_CODE(TYPE_NAME(type)) == IDENTIFIER_NODE)
Name = IDENTIFIER_POINTER(TYPE_NAME(type));
else if (DECL_NAME(TYPE_NAME(type)))
Name = IDENTIFIER_POINTER(DECL_NAME(TYPE_NAME(type)));
}
std::string ContextStr;
tree Context = TYPE_CONTEXT(type);
while (Context) {
switch (TREE_CODE(Context)) {
case TRANSLATION_UNIT_DECL: Context = 0; break; // Done.
case RECORD_TYPE:
case NAMESPACE_DECL:
if (TREE_CODE(Context) == RECORD_TYPE) {
if (TYPE_NAME(Context)) {
std::string NameFrag;
if (TREE_CODE(TYPE_NAME(Context)) == IDENTIFIER_NODE) {
NameFrag = IDENTIFIER_POINTER(TYPE_NAME(Context));
} else {
NameFrag = IDENTIFIER_POINTER(DECL_NAME(TYPE_NAME(Context)));
}
ContextStr = NameFrag + "::" + ContextStr;
Context = TYPE_CONTEXT(Context);
break;
}
// Anonymous record, fall through.
} else if (DECL_NAME(Context)
/*&& DECL_NAME(Context) != anonymous_namespace_name*/){
assert(TREE_CODE(DECL_NAME(Context)) == IDENTIFIER_NODE);
std::string NamespaceName = IDENTIFIER_POINTER(DECL_NAME(Context));
ContextStr = NamespaceName + "::" + ContextStr;
Context = DECL_CONTEXT(Context);
break;
}
// FALL THROUGH for anonymous namespaces and records!
default: {
// If this is a structure type defined inside of a function or other block
// scope, make sure to make the type name unique by putting a unique ID
// in it.
static unsigned UniqueID = 0;
ContextStr = "." + utostr(UniqueID++);
Context = 0; // Stop looking at context
break;
}
}
}
return Prefix + ContextStr + Name;
}
/// isSequentialCompatible - Return true if the specified gcc array or pointer
/// type and the corresponding LLVM SequentialType lay out their components
/// identically in memory, so doing a GEP accesses the right memory location.
/// We assume that objects without a known size do not.
bool isSequentialCompatible(tree_node *type) {
assert((TREE_CODE(type) == ARRAY_TYPE ||
TREE_CODE(type) == POINTER_TYPE ||
TREE_CODE(type) == REFERENCE_TYPE ||
TREE_CODE(type) == BLOCK_POINTER_TYPE) && "not a sequential type!");
// This relies on gcc types with constant size mapping to LLVM types with the
// same size. It is possible for the component type not to have a size:
// struct foo; extern foo bar[];
return TYPE_SIZE(TREE_TYPE(type)) &&
isInt64(TYPE_SIZE(TREE_TYPE(type)), true);
}
/// isBitfield - Returns whether to treat the specified field as a bitfield.
bool isBitfield(tree_node *field_decl) {
tree type = DECL_BIT_FIELD_TYPE(field_decl);
if (!type)
return false;
// A bitfield. But do we need to treat it as one?
assert(DECL_FIELD_BIT_OFFSET(field_decl) && "Bitfield with no bit offset!");
if (TREE_INT_CST_LOW(DECL_FIELD_BIT_OFFSET(field_decl)) & 7)
// Does not start on a byte boundary - must treat as a bitfield.
return true;
if (!TYPE_SIZE(type) || !isInt64(TYPE_SIZE (type), true))
// No size or variable sized - play safe, treat as a bitfield.
return true;
uint64_t TypeSizeInBits = getInt64(TYPE_SIZE (type), true);
assert(!(TypeSizeInBits & 7) && "A type with a non-byte size!");
assert(DECL_SIZE(field_decl) && "Bitfield with no bit size!");
uint64_t FieldSizeInBits = getInt64(DECL_SIZE(field_decl), true);
if (FieldSizeInBits < TypeSizeInBits)
// Not wide enough to hold the entire type - treat as a bitfield.
return true;
return false;
}
/// getDeclaredType - Get the declared type for the specified field_decl, and
/// not the shrunk-to-fit type that GCC gives us in TREE_TYPE.
tree getDeclaredType(tree_node *field_decl) {
return DECL_BIT_FIELD_TYPE(field_decl) ?
DECL_BIT_FIELD_TYPE(field_decl) : TREE_TYPE (field_decl);
}
//===----------------------------------------------------------------------===//
// Helper Routines
//===----------------------------------------------------------------------===//
/// getFieldOffsetInBits - Return the offset (in bits) of a FIELD_DECL in a
/// structure.
static uint64_t getFieldOffsetInBits(tree Field) {
assert(DECL_FIELD_BIT_OFFSET(Field) != 0 && DECL_FIELD_OFFSET(Field) != 0);
uint64_t Result = getInt64(DECL_FIELD_BIT_OFFSET(Field), true);
if (TREE_CODE(DECL_FIELD_OFFSET(Field)) == INTEGER_CST)
Result += getInt64(DECL_FIELD_OFFSET(Field), true)*8;
return Result;
}
/// FindLLVMTypePadding - If the specified struct has any inter-element padding,
/// add it to the Padding array.
static void FindLLVMTypePadding(Type *Ty, tree type, uint64_t BitOffset,
SmallVector<std::pair<uint64_t,uint64_t>, 16> &Padding) {
if (StructType *STy = dyn_cast<StructType>(Ty)) {
const TargetData &TD = getTargetData();
const StructLayout *SL = TD.getStructLayout(STy);
uint64_t PrevFieldEnd = 0;
for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i) {
// If this field is marked as being padding, then pretend it is not there.
// This results in it (or something bigger) being added to Padding. This
// matches the logic in CopyAggregate.
if (type && isPaddingElement(type, i))
continue;
uint64_t FieldBitOffset = SL->getElementOffset(i)*8;
// Get padding of sub-elements.
FindLLVMTypePadding(STy->getElementType(i), 0,
BitOffset+FieldBitOffset, Padding);
// Check to see if there is any padding between this element and the
// previous one.
if (PrevFieldEnd < FieldBitOffset)
Padding.push_back(std::make_pair(PrevFieldEnd+BitOffset,
FieldBitOffset-PrevFieldEnd));
PrevFieldEnd =
FieldBitOffset + TD.getTypeSizeInBits(STy->getElementType(i));
}
// Check for tail padding.
if (PrevFieldEnd < SL->getSizeInBits())
Padding.push_back(std::make_pair(PrevFieldEnd,
SL->getSizeInBits()-PrevFieldEnd));
} else if (const ArrayType *ATy = dyn_cast<ArrayType>(Ty)) {
uint64_t EltSize = getTargetData().getTypeSizeInBits(ATy->getElementType());
for (unsigned i = 0, e = ATy->getNumElements(); i != e; ++i)
FindLLVMTypePadding(ATy->getElementType(), 0, BitOffset+i*EltSize,
Padding);
}
// primitive and vector types have no padding.
}
/// GCCTypeOverlapsWithPadding - Return true if the specified gcc type overlaps
/// with the specified region of padding. This only needs to handle types with
/// a constant size.
static bool GCCTypeOverlapsWithPadding(tree type, int PadStartBits,
int PadSizeBits) {
assert(type != error_mark_node);
// LLVM doesn't care about variants such as const, volatile, or restrict.
type = TYPE_MAIN_VARIANT(type);
// If the type does not overlap, don't bother checking below.
if (!TYPE_SIZE(type))
// C-style variable length array? Be conservative.
return true;
if (!isInt64(TYPE_SIZE(type), true))
// Negative size (!) or huge - be conservative.
return true;
if (!getInt64(TYPE_SIZE(type), true) ||
PadStartBits >= (int64_t)getInt64(TYPE_SIZE(type), false) ||
PadStartBits+PadSizeBits <= 0)
return false;
switch (TREE_CODE(type)) {
default:
fprintf(stderr, "Unknown type to compare:\n");
debug_tree(type);
abort();
case VOID_TYPE:
case BOOLEAN_TYPE:
case ENUMERAL_TYPE:
case INTEGER_TYPE:
case REAL_TYPE:
case COMPLEX_TYPE:
case VECTOR_TYPE:
case POINTER_TYPE:
case REFERENCE_TYPE:
case BLOCK_POINTER_TYPE:
case OFFSET_TYPE:
// These types have no holes.
return true;
case ARRAY_TYPE: {
unsigned EltSizeBits = TREE_INT_CST_LOW(TYPE_SIZE(TREE_TYPE(type)));
unsigned NumElts = cast<ArrayType>(ConvertType(type))->getNumElements();
// Check each element for overlap. This is inelegant, but effective.
for (unsigned i = 0; i != NumElts; ++i)
if (GCCTypeOverlapsWithPadding(TREE_TYPE(type),
PadStartBits- i*EltSizeBits, PadSizeBits))
return true;
return false;
}
case QUAL_UNION_TYPE:
case UNION_TYPE: {
// If this is a union with the transparent_union attribute set, it is
// treated as if it were just the same as its first type.
if (TYPE_TRANSPARENT_UNION(type)) {
tree Field = TYPE_FIELDS(type);
assert(Field && "Transparent union must have some elements!");
while (TREE_CODE(Field) != FIELD_DECL) {
Field = TREE_CHAIN(Field);
assert(Field && "Transparent union must have some elements!");
}
return GCCTypeOverlapsWithPadding(TREE_TYPE(Field),
PadStartBits, PadSizeBits);
}
// See if any elements overlap.
for (tree Field = TYPE_FIELDS(type); Field; Field = TREE_CHAIN(Field)) {
if (TREE_CODE(Field) != FIELD_DECL) continue;
assert(getFieldOffsetInBits(Field) == 0 && "Union with non-zero offset?");
// Skip fields that are known not to be present.
if (TREE_CODE(type) == QUAL_UNION_TYPE &&
integer_zerop(DECL_QUALIFIER(Field)))
continue;
if (GCCTypeOverlapsWithPadding(TREE_TYPE(Field),
PadStartBits, PadSizeBits))
return true;
// Skip remaining fields if this one is known to be present.
if (TREE_CODE(type) == QUAL_UNION_TYPE &&
integer_onep(DECL_QUALIFIER(Field)))
break;
}
return false;
}
case RECORD_TYPE:
for (tree Field = TYPE_FIELDS(type); Field; Field = TREE_CHAIN(Field)) {
if (TREE_CODE(Field) != FIELD_DECL) continue;
if (TREE_CODE(DECL_FIELD_OFFSET(Field)) != INTEGER_CST)
return true;
uint64_t FieldBitOffset = getFieldOffsetInBits(Field);
if (GCCTypeOverlapsWithPadding(getDeclaredType(Field),
PadStartBits-FieldBitOffset, PadSizeBits))
return true;
}
return false;
}
}
bool TypeConverter::GCCTypeOverlapsWithLLVMTypePadding(tree type,
Type *Ty) {
// Start by finding all of the padding in the LLVM Type.
SmallVector<std::pair<uint64_t,uint64_t>, 16> StructPadding;
FindLLVMTypePadding(Ty, type, 0, StructPadding);
for (unsigned i = 0, e = StructPadding.size(); i != e; ++i)
if (GCCTypeOverlapsWithPadding(type, StructPadding[i].first,
StructPadding[i].second))
return true;
return false;
}
//===----------------------------------------------------------------------===//
// Main Type Conversion Routines
//===----------------------------------------------------------------------===//
Type *TypeConverter::ConvertType(tree orig_type) {
if (orig_type == error_mark_node) return Type::getInt32Ty(Context);
// LLVM doesn't care about variants such as const, volatile, or restrict.
tree type = TYPE_MAIN_VARIANT(orig_type);
switch (TREE_CODE(type)) {
default:
fprintf(stderr, "Unknown type to convert:\n");
debug_tree(type);
abort();
case VOID_TYPE: return SET_TYPE_LLVM(type, Type::getVoidTy(Context));
case RECORD_TYPE:
case QUAL_UNION_TYPE:
case UNION_TYPE: return ConvertRECORD(type, orig_type);
case BOOLEAN_TYPE: {
if (Type *Ty = GET_TYPE_LLVM(type))
return Ty;
return SET_TYPE_LLVM(type,
IntegerType::get(Context, TREE_INT_CST_LOW(TYPE_SIZE(type))));
}
case ENUMERAL_TYPE:
// Use of an enum that is implicitly declared?
if (TYPE_SIZE(orig_type) == 0) {
// If we already compiled this type, use the old type.
if (Type *Ty = GET_TYPE_LLVM(orig_type))
return Ty;
// Just mark it as a named type for now.
Type *Ty = StructType::create(Context, GetTypeName("enum.", orig_type));
return SET_TYPE_LLVM(orig_type, Ty);
}
// FALL THROUGH.
type = orig_type;
case INTEGER_TYPE: {
if (Type *Ty = GET_TYPE_LLVM(type)) return Ty;
// The ARM port defines __builtin_neon_xi as a 511-bit type because GCC's
// type precision field has only 9 bits. Treat this as a special case.
int precision = TYPE_PRECISION(type) == 511 ? 512 : TYPE_PRECISION(type);
return SET_TYPE_LLVM(type, IntegerType::get(Context, precision));
}
case REAL_TYPE:
if (Type *Ty = GET_TYPE_LLVM(type)) return Ty;
switch (TYPE_PRECISION(type)) {
default:
fprintf(stderr, "Unknown FP type!\n");
debug_tree(type);
abort();
// Half precision FP is a storage only format, use i16 for it.
case 16: return SET_TYPE_LLVM(type, Type::getInt16Ty(Context));
case 32: return SET_TYPE_LLVM(type, Type::getFloatTy(Context));
case 64: return SET_TYPE_LLVM(type, Type::getDoubleTy(Context));
case 80: return SET_TYPE_LLVM(type, Type::getX86_FP80Ty(Context));
case 128:
#ifdef TARGET_POWERPC
return SET_TYPE_LLVM(type, Type::getPPC_FP128Ty(Context));
#elif defined(TARGET_ZARCH) || defined(TARGET_CPU_sparc) // FIXME: Use some generic define.
// This is for IEEE double extended, e.g. Sparc
return SET_TYPE_LLVM(type, Type::getFP128Ty(Context));
#else
// 128-bit long doubles map onto { double, double }.
return SET_TYPE_LLVM(type,
StructType::get(Type::getDoubleTy(Context),
Type::getDoubleTy(Context), NULL));
#endif
}
case COMPLEX_TYPE: {
if (Type *Ty = GET_TYPE_LLVM(type)) return Ty;
Type *Ty = ConvertType(TREE_TYPE(type));
return SET_TYPE_LLVM(type, StructType::get(Ty, Ty, NULL));
}
case VECTOR_TYPE: {
if (Type *Ty = GET_TYPE_LLVM(type)) return Ty;
Type *Ty = ConvertType(TREE_TYPE(type));
Ty = VectorType::get(Ty, TYPE_VECTOR_SUBPARTS(type));
return SET_TYPE_LLVM(type, Ty);
}
case POINTER_TYPE:
case REFERENCE_TYPE:
case BLOCK_POINTER_TYPE: {
// Disable recursive struct conversion.
ConversionStatus SavedCS = RecursionStatus;
if (RecursionStatus == CS_Struct)
RecursionStatus = CS_StructPtr;
Type *Ty;
if (RecursionStatus != CS_StructPtr)
Ty = ConvertType(TREE_TYPE(type));
else
// FIXME: Hack to avoid crashes with the new LLVM type system.
Ty = Type::getInt8Ty(Context);
RecursionStatus = SavedCS;
if (Ty->isVoidTy())
Ty = Type::getInt8Ty(Context); // void* -> i8*
return SET_TYPE_LLVM(type, Ty->getPointerTo());
}
case METHOD_TYPE:
case FUNCTION_TYPE: {
if (Type *Ty = GET_TYPE_LLVM(type))
return Ty;
// No declaration to pass through, passing NULL.
CallingConv::ID CallingConv;
AttrListPtr PAL;
return SET_TYPE_LLVM(type, ConvertFunctionType(type, NULL, NULL,
CallingConv, PAL));
}
case ARRAY_TYPE: {
if (Type *Ty = GET_TYPE_LLVM(type))
return Ty;
uint64_t ElementSize;
Type *ElementTy;
if (isSequentialCompatible(type)) {
// The gcc element type maps to an LLVM type of the same size.
// Convert to an LLVM array of the converted element type.
ElementSize = getInt64(TYPE_SIZE(TREE_TYPE(type)), true);
ElementTy = ConvertType(TREE_TYPE(type));
} else {
// The gcc element type has no size, or has variable size. Convert to an
// LLVM array of bytes. In the unlikely but theoretically possible case
// that the gcc array type has constant size, using an i8 for the element
// type ensures we can produce an LLVM array of the right size.
ElementSize = 8;
ElementTy = Type::getInt8Ty(Context);
}
uint64_t NumElements;
if (!TYPE_SIZE(type)) {
// We get here if we have something that is declared to be an array with
// no dimension. This just becomes a zero length array of the element
// type, so 'int X[]' becomes '%X = external global [0 x i32]'.
//
// Note that this also affects new expressions, which return a pointer
// to an unsized array of elements.
NumElements = 0;
} else if (!isInt64(TYPE_SIZE(type), true)) {
// This handles cases like "int A[n]" which have a runtime constant
// number of elements, but is a compile-time variable. Since these
// are variable sized, we represent them as [0 x type].
NumElements = 0;
} else if (integer_zerop(TYPE_SIZE(type))) {
// An array of zero length, or with an element type of zero size.
// Turn it into a zero length array of the element type.
NumElements = 0;
} else {
// Normal constant-size array.
assert(ElementSize
&& "Array of positive size with elements of zero size!");
NumElements = getInt64(TYPE_SIZE(type), true);
assert(!(NumElements % ElementSize)
&& "Array size is not a multiple of the element size!");
NumElements /= ElementSize;
}
return SET_TYPE_LLVM(type, ArrayType::get(ElementTy, NumElements));
}
case OFFSET_TYPE:
// Handle OFFSET_TYPE specially. This is used for pointers to members,
// which are really just integer offsets. As such, return the appropriate
// integer directly.
switch (getTargetData().getPointerSize()) {
default: assert(0 && "Unknown pointer size!");
case 4: return Type::getInt32Ty(Context);
case 8: return Type::getInt64Ty(Context);
}
}
}
//===----------------------------------------------------------------------===//
// FUNCTION/METHOD_TYPE Conversion Routines
//===----------------------------------------------------------------------===//
namespace {
class FunctionTypeConversion : public DefaultABIClient {
Type *&RetTy;
std::vector<Type*> &ArgTypes;
CallingConv::ID &CallingConv;
bool isShadowRet;
bool KNRPromotion;
unsigned Offset;
public:
FunctionTypeConversion(Type *&retty, std::vector<Type*> &AT,
CallingConv::ID &CC, bool KNR)
: RetTy(retty), ArgTypes(AT), CallingConv(CC), KNRPromotion(KNR), Offset(0) {
CallingConv = CallingConv::C;
isShadowRet = false;
}
/// getCallingConv - This provides the desired CallingConv for the function.
CallingConv::ID &getCallingConv(void) { return CallingConv; }
bool isShadowReturn() const { return isShadowRet; }
/// HandleScalarResult - This callback is invoked if the function returns a
/// simple scalar result value.
void HandleScalarResult(Type *RetTy) {
this->RetTy = RetTy;
}
/// HandleAggregateResultAsScalar - This callback is invoked if the function
/// returns an aggregate value by bit converting it to the specified scalar
/// type and returning that.
void HandleAggregateResultAsScalar(Type *ScalarTy, unsigned Offset=0) {
RetTy = ScalarTy;
this->Offset = Offset;
}
/// HandleAggregateResultAsAggregate - This callback is invoked if the function
/// returns an aggregate value using multiple return values.
void HandleAggregateResultAsAggregate(Type *AggrTy) {
RetTy = AggrTy;
}
/// HandleShadowResult - Handle an aggregate or scalar shadow argument.
void HandleShadowResult(PointerType *PtrArgTy, bool RetPtr) {
// This function either returns void or the shadow argument,
// depending on the target.
RetTy = RetPtr ? PtrArgTy : Type::getVoidTy(Context);
// In any case, there is a dummy shadow argument though!
ArgTypes.push_back(PtrArgTy);
// Also, note the use of a shadow argument.
isShadowRet = true;
}
/// HandleAggregateShadowResult - This callback is invoked if the function
/// returns an aggregate value by using a "shadow" first parameter, which is
/// a pointer to the aggregate, of type PtrArgTy. If RetPtr is set to true,
/// the pointer argument itself is returned from the function.
void HandleAggregateShadowResult(PointerType *PtrArgTy, bool RetPtr) {
HandleShadowResult(PtrArgTy, RetPtr);
}
/// HandleScalarShadowResult - This callback is invoked if the function
/// returns a scalar value by using a "shadow" first parameter, which is a
/// pointer to the scalar, of type PtrArgTy. If RetPtr is set to true,
/// the pointer argument itself is returned from the function.
void HandleScalarShadowResult(PointerType *PtrArgTy, bool RetPtr) {
HandleShadowResult(PtrArgTy, RetPtr);
}
void HandlePad(llvm::Type *LLVMTy) {
HandleScalarArgument(LLVMTy, 0, 0);
}
void HandleScalarArgument(llvm::Type *LLVMTy, tree type,
unsigned RealSize = 0) {
if (KNRPromotion) {
if (type == float_type_node)
LLVMTy = ConvertType(double_type_node);
else if (LLVMTy->isIntegerTy(16) || LLVMTy->isIntegerTy(8) ||
LLVMTy->isIntegerTy(1))
LLVMTy = Type::getInt32Ty(Context);
}
LLVMTy = LLVM_ADJUST_MMX_PARAMETER_TYPE(LLVMTy);
ArgTypes.push_back(LLVMTy);
}
/// HandleByInvisibleReferenceArgument - This callback is invoked if a pointer
/// (of type PtrTy) to the argument is passed rather than the argument itself.
void HandleByInvisibleReferenceArgument(llvm::Type *PtrTy, tree type) {
ArgTypes.push_back(PtrTy);
}
/// HandleByValArgument - This callback is invoked if the aggregate function
/// argument is passed by value. It is lowered to a parameter passed by
/// reference with an additional parameter attribute "ByVal".
void HandleByValArgument(llvm::Type *LLVMTy, tree type) {
HandleScalarArgument(LLVMTy->getPointerTo(), type);
}
/// HandleFCAArgument - This callback is invoked if the aggregate function
/// argument is a first class aggregate passed by value.
void HandleFCAArgument(llvm::Type *LLVMTy,
tree type ATTRIBUTE_UNUSED) {
ArgTypes.push_back(LLVMTy);
}
};
}
static Attributes HandleArgumentExtension(tree ArgTy) {
if (TREE_CODE(ArgTy) == BOOLEAN_TYPE) {
if (TREE_INT_CST_LOW(TYPE_SIZE(ArgTy)) < INT_TYPE_SIZE)
return Attribute::ZExt;
} else if (TREE_CODE(ArgTy) == INTEGER_TYPE &&
TREE_INT_CST_LOW(TYPE_SIZE(ArgTy)) < INT_TYPE_SIZE) {
if (TYPE_UNSIGNED(ArgTy))
return Attribute::ZExt;
else
return Attribute::SExt;
}
return Attribute::None;
}
/// ConvertParamListToLLVMSignature - This method is used to build the argument
/// type list for K&R prototyped functions. In this case, we have to figure out
/// the type list (to build a FunctionType) from the actual DECL_ARGUMENTS list
/// for the function. This method takes the DECL_ARGUMENTS list (Args), and
/// fills in Result with the argument types for the function. It returns the
/// specified result type for the function.
FunctionType *TypeConverter::
ConvertArgListToFnType(tree type, tree Args, tree static_chain,
CallingConv::ID &CallingConv, AttrListPtr &PAL) {
tree ReturnType = TREE_TYPE(type);
std::vector<Type*> ArgTys;
Type *RetTy = Type::getVoidTy(Context);
FunctionTypeConversion Client(RetTy, ArgTys, CallingConv, true /*K&R*/);
DefaultABI ABIConverter(Client);
#ifdef TARGET_ADJUST_LLVM_CC
TARGET_ADJUST_LLVM_CC(CallingConv, type);
#endif
std::vector<Type*> ScalarArgs;
// Builtins are always prototyped, so this isn't one.
ABIConverter.HandleReturnType(ReturnType, current_function_decl, false,
ScalarArgs);
SmallVector<AttributeWithIndex, 8> Attrs;
// Compute whether the result needs to be zext or sext'd.
Attributes RAttributes = HandleArgumentExtension(ReturnType);
// Allow the target to change the attributes.
#ifdef TARGET_ADJUST_LLVM_RETATTR
TARGET_ADJUST_LLVM_RETATTR(RAttributes, type);
#endif
if (RAttributes != Attribute::None)
Attrs.push_back(AttributeWithIndex::get(0, RAttributes));
// If this function returns via a shadow argument, the dest loc is passed
// in as a pointer. Mark that pointer as struct-ret.
//
// It's tempting to want NoAlias here too, however even though llvm-gcc
// itself currently always passes a dedicated alloca as the actual argument,
// this isn't mandated by the ABI. There are other compilers which don't
// always pass a dedicated alloca. Using NoAlias here would make code which
// isn't interoperable with that of other compilers.
if (ABIConverter.isShadowReturn())
Attrs.push_back(AttributeWithIndex::get(ArgTys.size(),
Attribute::StructRet));
if (static_chain) {
// Pass the static chain as the first parameter.
ABIConverter.HandleArgument(TREE_TYPE(static_chain), ScalarArgs);
// Mark it as the chain argument.
Attrs.push_back(AttributeWithIndex::get(ArgTys.size(),
Attribute::Nest));
}
for (; Args && TREE_TYPE(Args) != void_type_node; Args = TREE_CHAIN(Args)) {
tree ArgTy = TREE_TYPE(Args);
// Determine if there are any attributes for this param.
Attributes PAttributes = Attribute::None;
ABIConverter.HandleArgument(ArgTy, ScalarArgs, &PAttributes);
// Compute zext/sext attributes.
PAttributes |= HandleArgumentExtension(ArgTy);
if (PAttributes != Attribute::None)
Attrs.push_back(AttributeWithIndex::get(ArgTys.size(), PAttributes));
}
PAL = AttrListPtr::get(Attrs.begin(), Attrs.end());
return FunctionType::get(RetTy, ArgTys, false);
}
FunctionType *TypeConverter::
ConvertFunctionType(tree type, tree decl, tree static_chain,
CallingConv::ID &CallingConv, AttrListPtr &PAL) {
Type *RetTy = Type::getVoidTy(Context);
std::vector<Type *> ArgTypes;
bool isVarArg = false;
FunctionTypeConversion Client(RetTy, ArgTypes, CallingConv, false/*not K&R*/);
DefaultABI ABIConverter(Client);
// Allow the target to set the CC for things like fastcall etc.
#ifdef TARGET_ADJUST_LLVM_CC
TARGET_ADJUST_LLVM_CC(CallingConv, type);
#endif
std::vector<Type*> ScalarArgs;
ABIConverter.HandleReturnType(TREE_TYPE(type), current_function_decl,
decl ? DECL_BUILT_IN(decl) : false,
ScalarArgs);
// Compute attributes for return type (and function attributes).
SmallVector<AttributeWithIndex, 8> Attrs;
Attributes FnAttributes = Attribute::None;
int flags = flags_from_decl_or_type(decl ? decl : type);
// Check for 'noreturn' function attribute.
if (flags & ECF_NORETURN)
FnAttributes |= Attribute::NoReturn;
// Check for 'nounwind' function attribute.
if (flags & ECF_NOTHROW)
FnAttributes |= Attribute::NoUnwind;
// Check for 'returnstwice' function attribute.
if (flags & ECF_RETURNS_TWICE)
FnAttributes |= Attribute::ReturnsTwice;
// Check for 'readnone' function attribute.
// Both PURE and CONST will be set if the user applied
// __attribute__((const)) to a function the compiler
// knows to be pure, such as log. A user or (more
// likely) libm implementor might know their local log
// is in fact const, so this should be valid (and gcc
// accepts it). But llvm IR does not allow both, so
// set only ReadNone.
if (flags & ECF_CONST)
FnAttributes |= Attribute::ReadNone;
// Check for 'readonly' function attribute.
if (flags & ECF_PURE && !(flags & ECF_CONST))
FnAttributes |= Attribute::ReadOnly;
// Since they write the return value through a pointer,
// 'sret' functions cannot be 'readnone' or 'readonly'.
if (ABIConverter.isShadowReturn())
FnAttributes &= ~(Attribute::ReadNone|Attribute::ReadOnly);
// Demote 'readnone' nested functions to 'readonly' since
// they may need to read through the static chain.
if (static_chain && (FnAttributes & Attribute::ReadNone)) {
FnAttributes &= ~Attribute::ReadNone;
FnAttributes |= Attribute::ReadOnly;
}
// Compute whether the result needs to be zext or sext'd.
Attributes RAttributes = Attribute::None;
RAttributes |= HandleArgumentExtension(TREE_TYPE(type));
// Allow the target to change the attributes.
#ifdef TARGET_ADJUST_LLVM_RETATTR
TARGET_ADJUST_LLVM_RETATTR(RAttributes, type);
#endif
// The value returned by a 'malloc' function does not alias anything.
if (flags & ECF_MALLOC)
RAttributes |= Attribute::NoAlias;
if (RAttributes != Attribute::None)
Attrs.push_back(AttributeWithIndex::get(0, RAttributes));
// If this function returns via a shadow argument, the dest loc is passed
// in as a pointer. Mark that pointer as struct-ret and noalias.
if (ABIConverter.isShadowReturn())
Attrs.push_back(AttributeWithIndex::get(ArgTypes.size(),
Attribute::StructRet | Attribute::NoAlias));
if (static_chain) {
// Pass the static chain as the first parameter.
ABIConverter.HandleArgument(TREE_TYPE(static_chain), ScalarArgs);
// Mark it as the chain argument.
Attrs.push_back(AttributeWithIndex::get(ArgTypes.size(),
Attribute::Nest));
}
// If the target has regparam parameters, allow it to inspect the function
// type.
int local_regparam = 0;
int local_fp_regparam = 0;
#ifdef LLVM_TARGET_ENABLE_REGPARM
LLVM_TARGET_INIT_REGPARM(local_regparam, local_fp_regparam, type);
#endif // LLVM_TARGET_ENABLE_REGPARM
// Keep track of whether we see a byval argument.
bool HasByVal = false;
// Check if we have a corresponding decl to inspect.
tree DeclArgs = (decl) ? DECL_ARGUMENTS(decl) : NULL;
// Loop over all of the arguments, adding them as we go.
tree Args = TYPE_ARG_TYPES(type);
for (; Args && TREE_VALUE(Args) != void_type_node; Args = TREE_CHAIN(Args)){
tree ArgTy = TREE_VALUE(Args);
if (!isPassedByInvisibleReference(ArgTy))
if (StructType *STy = dyn_cast<StructType>(ConvertType(ArgTy)))
if (STy->isOpaque()) {
// If we are passing an opaque struct by value, we don't know how many
// arguments it will turn into. Because we can't handle this yet,
// codegen the prototype as (...).
if (CallingConv == CallingConv::C)
ArgTypes.clear();
else
// Don't nuke last argument.
ArgTypes.erase(ArgTypes.begin()+1, ArgTypes.end());
Args = 0;
break;
}
// Determine if there are any attributes for this param.
Attributes PAttributes = Attribute::None;
unsigned OldSize = ArgTypes.size();
ABIConverter.HandleArgument(ArgTy, ScalarArgs, &PAttributes);
// Compute zext/sext attributes.
PAttributes |= HandleArgumentExtension(ArgTy);
// Compute noalias attributes. If we have a decl for the function
// inspect it for restrict qualifiers, otherwise try the argument
// types.
tree RestrictArgTy = (DeclArgs) ? TREE_TYPE(DeclArgs) : ArgTy;
if (TREE_CODE(RestrictArgTy) == POINTER_TYPE ||
TREE_CODE(RestrictArgTy) == REFERENCE_TYPE ||
TREE_CODE(RestrictArgTy) == BLOCK_POINTER_TYPE) {
if (TYPE_RESTRICT(RestrictArgTy))
PAttributes |= Attribute::NoAlias;
}
#ifdef LLVM_TARGET_ENABLE_REGPARM
// Allow the target to mark this as inreg.
if (INTEGRAL_TYPE_P(ArgTy) || POINTER_TYPE_P(ArgTy) ||
SCALAR_FLOAT_TYPE_P(ArgTy))
LLVM_ADJUST_REGPARM_ATTRIBUTE(PAttributes, ArgTy,
TREE_INT_CST_LOW(TYPE_SIZE(ArgTy)),
local_regparam, local_fp_regparam);
#endif // LLVM_TARGET_ENABLE_REGPARM
if (PAttributes != Attribute::None) {
HasByVal |= (PAttributes & Attribute::ByVal) != Attribute::None;
// If the argument is split into multiple scalars, assign the
// attributes to all scalars of the aggregate.
for (unsigned i = OldSize + 1; i <= ArgTypes.size(); ++i) {
Attrs.push_back(AttributeWithIndex::get(i, PAttributes));
}
}
if (DeclArgs)
DeclArgs = TREE_CHAIN(DeclArgs);
}
// If there is a byval argument then it is not safe to mark the function
// 'readnone' or 'readonly': gcc permits a 'const' or 'pure' function to
// write to struct arguments passed by value, but in LLVM this becomes a
// write through the byval pointer argument, which LLVM does not allow for
// readonly/readnone functions.
if (HasByVal)
FnAttributes &= ~(Attribute::ReadNone | Attribute::ReadOnly);
// If the argument list ends with a void type node, it isn't vararg.
isVarArg = (Args == 0);
assert(RetTy && "Return type not specified!");
if (FnAttributes != Attribute::None)
Attrs.push_back(AttributeWithIndex::get(~0, FnAttributes));
// Finally, make the function type and result attributes.
PAL = AttrListPtr::get(Attrs.begin(), Attrs.end());
return FunctionType::get(RetTy, ArgTypes, isVarArg);
}
//===----------------------------------------------------------------------===//
// RECORD/Struct Conversion Routines
//===----------------------------------------------------------------------===//
/// StructTypeConversionInfo - A temporary structure that is used when
/// translating a RECORD_TYPE to an LLVM type.
struct StructTypeConversionInfo {
std::vector<Type*> Elements;
std::vector<uint64_t> ElementOffsetInBytes;
std::vector<uint64_t> ElementSizeInBytes;
std::vector<bool> PaddingElement; // True if field is used for padding
const TargetData &TD;
unsigned GCCStructAlignmentInBytes;
bool Packed; // True if struct is packed
bool AllBitFields; // True if all struct fields are bit fields
bool LastFieldStartsAtNonByteBoundry;
unsigned ExtraBitsAvailable; // Non-zero if last field is bit field and it
// does not use all allocated bits
StructTypeConversionInfo(TargetMachine &TM, unsigned GCCAlign, bool P)
: TD(*TM.getTargetData()), GCCStructAlignmentInBytes(GCCAlign),
Packed(P), AllBitFields(true), LastFieldStartsAtNonByteBoundry(false),
ExtraBitsAvailable(0) {}
void lastFieldStartsAtNonByteBoundry(bool value) {
LastFieldStartsAtNonByteBoundry = value;
}
void extraBitsAvailable (unsigned E) {
ExtraBitsAvailable = E;
}
bool isPacked() { return Packed; }
void markAsPacked() {
Packed = true;
}
void allFieldsAreNotBitFields() {
AllBitFields = false;
// Next field is not a bitfield.
LastFieldStartsAtNonByteBoundry = false;
}
unsigned getGCCStructAlignmentInBytes() const {
return GCCStructAlignmentInBytes;
}
/// getTypeAlignment - Return the alignment of the specified type in bytes.
///
unsigned getTypeAlignment(Type *Ty) const {
return Packed ? 1 : TD.getABITypeAlignment(Ty);
}
/// getTypeSize - Return the size of the specified type in bytes.
///
uint64_t getTypeSize(Type *Ty) const {
return TD.getTypeAllocSize(Ty);
}
/// fillInLLVMType - Return the LLVM type for the specified object.
///
void fillInLLVMType(StructType *STy) const {
// Use Packed type if Packed is set or all struct fields are bitfields.
// Empty struct is not packed unless packed is set.
STy->setBody(Elements, Packed || (!Elements.empty() && AllBitFields));
}
/// getAlignmentAsLLVMStruct - Return the alignment of this struct if it were
/// converted to an LLVM type.
uint64_t getAlignmentAsLLVMStruct() const {
if (Packed || AllBitFields) return 1;
unsigned MaxAlign = 1;
for (unsigned i = 0, e = Elements.size(); i != e; ++i)
MaxAlign = std::max(MaxAlign, getTypeAlignment(Elements[i]));
return MaxAlign;
}
/// getSizeAsLLVMStruct - Return the size of this struct if it were converted
/// to an LLVM type. This is the end of last element push an alignment pad at
/// the end.
uint64_t getSizeAsLLVMStruct() const {
if (Elements.empty()) return 0;
unsigned MaxAlign = getAlignmentAsLLVMStruct();
uint64_t Size = ElementOffsetInBytes.back()+ElementSizeInBytes.back();
return (Size+MaxAlign-1) & ~(MaxAlign-1);
}
// If this is a Packed struct and ExtraBitsAvailable is not zero then
// remove Extra bytes if ExtraBitsAvailable > 8.
void RemoveExtraBytes () {
unsigned NoOfBytesToRemove = ExtraBitsAvailable/8;
if (!Packed && !AllBitFields)
return;
if (NoOfBytesToRemove == 0)
return;
Type *LastType = Elements.back();
unsigned PadBytes = 0;
if (LastType->isIntegerTy(8))
PadBytes = 1 - NoOfBytesToRemove;
else if (LastType->isIntegerTy(16))
PadBytes = 2 - NoOfBytesToRemove;
else if (LastType->isIntegerTy(32))
PadBytes = 4 - NoOfBytesToRemove;
else if (LastType->isIntegerTy(64))
PadBytes = 8 - NoOfBytesToRemove;
else
return;
assert (PadBytes > 0 && "Unable to remove extra bytes");
// Update last element type and size, element offset is unchanged.
Type *Pad = ArrayType::get(Type::getInt8Ty(Context), PadBytes);
unsigned OriginalSize = ElementSizeInBytes.back();
Elements.pop_back();
Elements.push_back(Pad);
ElementSizeInBytes.pop_back();
ElementSizeInBytes.push_back(OriginalSize - NoOfBytesToRemove);
}
/// ResizeLastElementIfOverlapsWith - If the last element in the struct
/// includes the specified byte, remove it. Return true struct
/// layout is sized properly. Return false if unable to handle ByteOffset.
/// In this case caller should redo this struct as a packed structure.
bool ResizeLastElementIfOverlapsWith(uint64_t ByteOffset, tree Field,
Type *Ty) {
Type *SavedTy = NULL;
if (!Elements.empty()) {
assert(ElementOffsetInBytes.back() <= ByteOffset &&
"Cannot go backwards in struct");
SavedTy = Elements.back();
if (ElementOffsetInBytes.back()+ElementSizeInBytes.back() > ByteOffset) {
// The last element overlapped with this one, remove it.
uint64_t PoppedOffset = ElementOffsetInBytes.back();
Elements.pop_back();
ElementOffsetInBytes.pop_back();
ElementSizeInBytes.pop_back();
PaddingElement.pop_back();
uint64_t EndOffset = getNewElementByteOffset(1);
if (EndOffset < PoppedOffset) {
// Make sure that some field starts at the position of the
// field we just popped. Otherwise we might end up with a
// gcc non-bitfield being mapped to an LLVM field with a
// different offset.
Type *Pad = Type::getInt8Ty(Context);
if (PoppedOffset != EndOffset + 1)
Pad = ArrayType::get(Pad, PoppedOffset - EndOffset);
addElement(Pad, EndOffset, PoppedOffset - EndOffset);
}
}
}
// Get the LLVM type for the field. If this field is a bitfield, use the
// declared type, not the shrunk-to-fit type that GCC gives us in TREE_TYPE.
unsigned ByteAlignment = getTypeAlignment(Ty);
uint64_t NextByteOffset = getNewElementByteOffset(ByteAlignment);
if (NextByteOffset > ByteOffset ||
ByteAlignment > getGCCStructAlignmentInBytes()) {
// LLVM disagrees as to where this field should go in the natural field
// ordering. Therefore convert to a packed struct and try again.
return false;
}
// If alignment won't round us up to the right boundary, insert explicit
// padding.
if (NextByteOffset < ByteOffset) {
uint64_t CurOffset = getNewElementByteOffset(1);
Type *Pad = Type::getInt8Ty(Context);
if (SavedTy && LastFieldStartsAtNonByteBoundry)
// We want to reuse SavedType to access this bit field.
// e.g. struct __attribute__((packed)) {
// unsigned int A,
// unsigned short B : 6,
// C : 15;
// char D; };
// In this example, previous field is C and D is current field.
addElement(SavedTy, CurOffset, ByteOffset - CurOffset);
else if (ByteOffset - CurOffset != 1)
Pad = ArrayType::get(Pad, ByteOffset - CurOffset);
addElement(Pad, CurOffset, ByteOffset - CurOffset);
}
return true;
}
/// FieldNo - Remove the specified field and all of the fields that come after
/// it.
void RemoveFieldsAfter(unsigned FieldNo) {
Elements.erase(Elements.begin()+FieldNo, Elements.end());
ElementOffsetInBytes.erase(ElementOffsetInBytes.begin()+FieldNo,
ElementOffsetInBytes.end());
ElementSizeInBytes.erase(ElementSizeInBytes.begin()+FieldNo,
ElementSizeInBytes.end());
PaddingElement.erase(PaddingElement.begin()+FieldNo,
PaddingElement.end());
}
/// getNewElementByteOffset - If we add a new element with the specified
/// alignment, what byte offset will it land at?
uint64_t getNewElementByteOffset(unsigned ByteAlignment) {
if (Elements.empty()) return 0;
uint64_t LastElementEnd =
ElementOffsetInBytes.back() + ElementSizeInBytes.back();
return (LastElementEnd+ByteAlignment-1) & ~(ByteAlignment-1);
}
/// addElement - Add an element to the structure with the specified type,
/// offset and size.
void addElement(Type *Ty, uint64_t Offset, uint64_t Size,
bool ExtraPadding = false) {
Elements.push_back((Type*)Ty);
ElementOffsetInBytes.push_back(Offset);
ElementSizeInBytes.push_back(Size);
PaddingElement.push_back(ExtraPadding);
lastFieldStartsAtNonByteBoundry(false);
ExtraBitsAvailable = 0;
}
/// getFieldEndOffsetInBytes - Return the byte offset of the byte immediately
/// after the specified field. For example, if FieldNo is 0 and the field
/// is 4 bytes in size, this will return 4.
uint64_t getFieldEndOffsetInBytes(unsigned FieldNo) const {
assert(FieldNo < ElementOffsetInBytes.size() && "Invalid field #!");
return ElementOffsetInBytes[FieldNo]+ElementSizeInBytes[FieldNo];
}
/// getEndUnallocatedByte - Return the first byte that isn't allocated at the
/// end of a structure. For example, for {}, it's 0, for {int} it is 4, for
/// {int,short}, it is 6.
uint64_t getEndUnallocatedByte() const {
if (ElementOffsetInBytes.empty()) return 0;
return getFieldEndOffsetInBytes(ElementOffsetInBytes.size()-1);
}
/// getLLVMFieldFor - When we are assigning indices to FieldDecls, this
/// method determines which struct element to use. Since the offset of
/// the fields cannot go backwards, CurFieldNo retains the last element we
/// looked at, to keep this a nice fast linear process. If isZeroSizeField
/// is true, this should return some zero sized field that starts at the
/// specified offset.
///
/// This returns the first field that contains the specified bit.
///
unsigned getLLVMFieldFor(uint64_t FieldOffsetInBits, unsigned &CurFieldNo,
bool isZeroSizeField) {
if (!isZeroSizeField) {
// Skip over LLVM fields that start and end before the GCC field starts.
while (CurFieldNo < ElementOffsetInBytes.size() &&
getFieldEndOffsetInBytes(CurFieldNo)*8 <= FieldOffsetInBits)
++CurFieldNo;
if (CurFieldNo < ElementOffsetInBytes.size())
return CurFieldNo;
// Otherwise, we couldn't find the field!
// FIXME: this works around a latent bug!
//assert(0 && "Could not find field!");
return ~0U;
}
// Handle zero sized fields now.
// Skip over LLVM fields that start and end before the GCC field starts.
// Such fields are always nonzero sized, and we don't want to skip past
// zero sized ones as well, which happens if you use only the Offset
// comparison.
while (CurFieldNo < ElementOffsetInBytes.size() &&
getFieldEndOffsetInBytes(CurFieldNo)*8 <
FieldOffsetInBits + (ElementSizeInBytes[CurFieldNo] != 0))
++CurFieldNo;
// If the next field is zero sized, advance past this one. This is a nicety
// that causes us to assign C fields different LLVM fields in cases like
// struct X {}; struct Y { struct X a, b, c };
if (CurFieldNo+1 < ElementOffsetInBytes.size() &&
ElementSizeInBytes[CurFieldNo+1] == 0) {
return CurFieldNo++;
}
// Otherwise, if this is a zero sized field, return it.
if (CurFieldNo < ElementOffsetInBytes.size() &&
ElementSizeInBytes[CurFieldNo] == 0) {
return CurFieldNo;
}
// Otherwise, we couldn't find the field!
assert(0 && "Could not find field!");
return ~0U;
}
void addNewBitField(uint64_t Size, uint64_t Extra,
uint64_t FirstUnallocatedByte);
void dump() const;
};
// Add new element which is a bit field. Size is not the size of bit field,
// but size of bits required to determine type of new Field which will be
// used to access this bit field.
// If possible, allocate a field with room for Size+Extra bits.
void StructTypeConversionInfo::addNewBitField(uint64_t Size, uint64_t Extra,
uint64_t FirstUnallocatedByte) {
// Figure out the LLVM type that we will use for the new field.
// Note, Size is not necessarily size of the new field. It indicates
// additional bits required after FirstunallocatedByte to cover new field.
Type *NewFieldTy = 0;
// First try an ABI-aligned field including (some of) the Extra bits.
// This field must satisfy Size <= w && w <= XSize.
uint64_t XSize = Size + Extra;
for (unsigned w = NextPowerOf2(std::min(UINT64_C(64), XSize))/2;
w >= Size && w >= 8; w /= 2) {
if (TD.isIllegalInteger(w))
continue;
// Would a w-sized integer field be aligned here?
const unsigned a = TD.getABIIntegerTypeAlignment(w);
if (FirstUnallocatedByte & (a-1) || a > getGCCStructAlignmentInBytes())
continue;
// OK, use w-sized integer.
NewFieldTy = IntegerType::get(Context, w);
break;
}
// Try an integer field that holds Size bits.
if (!NewFieldTy) {
if (Size <= 8)
NewFieldTy = Type::getInt8Ty(Context);
else if (Size <= 16)
NewFieldTy = Type::getInt16Ty(Context);
else if (Size <= 32)
NewFieldTy = Type::getInt32Ty(Context);
else {
assert(Size <= 64 && "Bitfield too large!");
NewFieldTy = Type::getInt64Ty(Context);
}
}
// Check that the alignment of NewFieldTy won't cause a gap in the structure!
unsigned ByteAlignment = getTypeAlignment(NewFieldTy);
if (FirstUnallocatedByte & (ByteAlignment-1) ||
ByteAlignment > getGCCStructAlignmentInBytes()) {
// Instead of inserting a nice whole field, insert a small array of ubytes.
NewFieldTy = ArrayType::get(Type::getInt8Ty(Context), (Size+7)/8);
}
// Finally, add the new field.
addElement(NewFieldTy, FirstUnallocatedByte, getTypeSize(NewFieldTy));
ExtraBitsAvailable = NewFieldTy->getPrimitiveSizeInBits() - Size;
}
void StructTypeConversionInfo::dump() const {
raw_ostream &OS = outs();
OS << "Info has " << Elements.size() << " fields:\n";
for (unsigned i = 0, e = Elements.size(); i != e; ++i) {
OS << " Offset = " << ElementOffsetInBytes[i]
<< " Size = " << ElementSizeInBytes[i]
<< " Type = " << *Elements[i] << "\n";
}
OS.flush();
}
std::map<tree, StructTypeConversionInfo *> StructTypeInfoMap;
/// Return true if and only if field no. N from struct type T is a padding
/// element added to match llvm struct type size and gcc struct type size.
bool isPaddingElement(tree type, unsigned index) {
StructTypeConversionInfo *Info = StructTypeInfoMap[type];
// If info is not available then be conservative and return false.
if (!Info)
return false;
assert ( Info->Elements.size() == Info->PaddingElement.size()
&& "Invalid StructTypeConversionInfo");
assert ( index < Info->PaddingElement.size()
&& "Invalid PaddingElement index");
return Info->PaddingElement[index];
}
/// OldTy and NewTy are union members. If they are representing
/// structs then adjust their PaddingElement bits. Padding
/// field in one struct may not be a padding field in another
/// struct.
void adjustPaddingElement(tree oldtree, tree newtree) {
StructTypeConversionInfo *OldInfo = StructTypeInfoMap[oldtree];
StructTypeConversionInfo *NewInfo = StructTypeInfoMap[newtree];
if (!OldInfo || !NewInfo)
return;
/// FIXME : Find overlapping padding fields and preserve their
/// isPaddingElement bit. For now, clear all isPaddingElement bits.
for (unsigned i = 0, size = NewInfo->PaddingElement.size(); i != size; ++i)
NewInfo->PaddingElement[i] = false;
for (unsigned i = 0, size = OldInfo->PaddingElement.size(); i != size; ++i)
OldInfo->PaddingElement[i] = false;
}
/// Mapping from type to type-used-as-base-class and back.
static DenseMap<std::pair<tree, unsigned int>, tree > BaseTypesMap;
/// FixBaseClassField - This method is called when we have a field Field
/// of Record type within a Record, and the size of Field is smaller than the
/// size of its Record type. This may indicate the situation where a base class
/// has virtual base classes which are not allocated. Replace Field's original
/// type with a modified one reflecting what actually gets allocated.
///
/// This can also occur when a class has an empty base class; the class will
/// have size N+4 and the field size N+1. In this case the fields will add
/// up to N+4, so we haven't really changed anything.
static tree FixBaseClassField(tree Field) {
tree oldTy = TREE_TYPE(Field);
std::pair<tree, unsigned int> p = std::make_pair(oldTy,
std::min(DECL_ALIGN(Field), TYPE_ALIGN(oldTy)));
tree newTy = BaseTypesMap[p];
// If already in table, reuse.
if (!newTy) {
newTy = copy_node(oldTy);
tree F2 = 0, prevF2 = 0, F;
// Copy the fields up to the TYPE_DECL separator.
// VAR_DECLs can also appear, representing static members. Possibly some
// other junk I haven't hit yet, just skip anything that's not a FIELD:(
for (F = TYPE_FIELDS(oldTy); F; prevF2 = F2, F = TREE_CHAIN(F)) {
if (TREE_CODE(F) == TYPE_DECL)
break;
if (TREE_CODE(F) == FIELD_DECL) {
F2 = copy_node(F);
if (prevF2)
TREE_CHAIN(prevF2) = F2;
else
TYPE_FIELDS(newTy) = F2;
TREE_CHAIN(F2) = 0;
}
}
// If we didn't find a TYPE_DECL this isn't the virtual base class case.
// The ObjC trees for bitfield instance variables can look similar enough
// to the C++ virtual base case to get this far, but these don't have
// the TYPE_DECL sentinel, nor the virtual base class allocation problem.
if (!F || TREE_CODE(F) != TYPE_DECL) {
BaseTypesMap[p] = oldTy;
return oldTy;
}
BaseTypesMap[p] = newTy;
BaseTypesMap[std::make_pair(newTy, 0U)] = oldTy;
// Prevent gcc's garbage collector from destroying newTy. The
// GC code doesn't understand DenseMaps:(
llvm_note_type_used(newTy);
TYPE_SIZE(newTy) = DECL_SIZE(Field);
TYPE_SIZE_UNIT(newTy) = DECL_SIZE_UNIT(Field);
// If the alignment of the field is smaller than the alignment of the type,
// we may not need tail padding in this context.
if (DECL_ALIGN(Field) < TYPE_ALIGN(newTy))
TYPE_ALIGN(newTy) = DECL_ALIGN(Field);
TYPE_MAIN_VARIANT(newTy) = newTy;
TYPE_STUB_DECL(newTy) = TYPE_STUB_DECL(oldTy);
// Change the name.
if (TYPE_NAME(oldTy)) {
const char *p = "anon";
if (TREE_CODE(TYPE_NAME(oldTy)) ==IDENTIFIER_NODE)
p = IDENTIFIER_POINTER(TYPE_NAME(oldTy));
else if (DECL_NAME(TYPE_NAME(oldTy)))
p = IDENTIFIER_POINTER(DECL_NAME(TYPE_NAME(oldTy)));
char *q = (char *)xmalloc(strlen(p)+20);
sprintf(q, "%s.base.%d", p, TYPE_ALIGN(newTy));
TYPE_NAME(newTy) = get_identifier(q);
free(q);
}
}
return newTy;
}
/// FixUpFields - alter the types referred to by Field nodes that
/// represent base classes to reflect reality.
//
// Suppose we're converting type T. Look for the case where a base class A
// of T contains a virtual base class B, and B is not allocated when A is
// used as the base class of T. This is indicated by the FIELD node for A
// having a size smaller than the size of A, and the chain of fields for A
// having a TYPE_DECL node in the middle of it; that node comes after the
// allocated fields and before the unallocated virtual base classes. Create
// a new type A.base for LLVM purposes which does not contain the virtual
// base classes. (Where A is a virtual base class of T, there is also a BINFO
// node for it, but not when A is a nonvirtual base class. So we can't
// use that.)
//
// If #pragma pack is involved, different derived classes may use different
// sizes for the base class. We also alter the types referred to by Field nodes
// that have greater alignment than the Field does; these might not get the
// tail padding as a Field that they get elsewhere. To handle these additional
// cases the size and alignment of the field are used as parts of the index
// into the map of base classes already created.
static void FixUpFields(tree type) {
if (TREE_CODE(type) != RECORD_TYPE)
return;
for (tree Field = TYPE_FIELDS(type); Field; Field = TREE_CHAIN(Field)) {
if (TREE_CODE(Field)==FIELD_DECL &&
!DECL_BIT_FIELD_TYPE(Field) &&
TREE_CODE(DECL_FIELD_OFFSET(Field))==INTEGER_CST &&
TREE_CODE(TREE_TYPE(Field))==RECORD_TYPE &&
TYPE_SIZE(TREE_TYPE(Field)) &&
DECL_SIZE(Field) &&
((TREE_CODE(DECL_SIZE(Field))==INTEGER_CST &&
TREE_CODE(TYPE_SIZE(TREE_TYPE(Field)))==INTEGER_CST &&
TREE_INT_CST_LOW(DECL_SIZE(Field)) <
TREE_INT_CST_LOW(TYPE_SIZE(TREE_TYPE(Field)))) ||
(DECL_ALIGN(Field) < TYPE_ALIGN(TREE_TYPE(Field))))) {
tree newType = FixBaseClassField(Field);
if (newType != TREE_TYPE(Field)) {
TREE_TYPE(Field) = newType;
DECL_FIELD_BASE_REPLACED(Field) = 1;
}
}
}
// Size of the complete type will be a multiple of its alignment.
// In some cases involving empty C++ classes this is not true coming in.
// Earlier, the sizes in the field types were also wrong in a way that
// compensated as far as LLVM's translation code is concerned; now we
// have fixed that, and have to fix the size also.
if (TYPE_SIZE (type) && TREE_CODE(TYPE_SIZE(type)) == INTEGER_CST) {
// This computes (size+align-1) & ~(align-1)
// NB "sizetype" is #define'd in one of the gcc headers. Gotcha!
tree size_type = TREE_TYPE(TYPE_SIZE(type));
tree alignm1 = fold_build2(PLUS_EXPR, size_type,
build_int_cst(size_type, TYPE_ALIGN(type)),
fold_build1(NEGATE_EXPR, size_type,
build_int_cst(size_type, 1)));
tree lhs = fold_build2(PLUS_EXPR, size_type, TYPE_SIZE(type), alignm1);
tree rhs = fold_build1(BIT_NOT_EXPR, size_type, alignm1);
TYPE_SIZE(type) = fold_build2(BIT_AND_EXPR, size_type, lhs, rhs);
size_type = TREE_TYPE(TYPE_SIZE_UNIT(type));
alignm1 = fold_build2(PLUS_EXPR, size_type,
build_int_cst(size_type, TYPE_ALIGN_UNIT(type)),
fold_build1(NEGATE_EXPR, size_type,
build_int_cst(size_type, 1)));
lhs = fold_build2(PLUS_EXPR, size_type, TYPE_SIZE_UNIT(type), alignm1);
rhs = fold_build1(BIT_NOT_EXPR, size_type, alignm1);
TYPE_SIZE_UNIT(type) = fold_build2(BIT_AND_EXPR, size_type, lhs, rhs);
}
}
// RestoreOriginalFields - put things back the way they were so the C++FE
// code continues to work (there are pointers stashed away in there).
static void RestoreOriginalFields(tree type) {
if (TREE_CODE(type)!=RECORD_TYPE)
return;
for (tree Field = TYPE_FIELDS(type); Field; Field = TREE_CHAIN(Field)) {
if (TREE_CODE(Field) == FIELD_DECL) {
if (DECL_FIELD_BASE_REPLACED(Field)) {
tree &oldTy = BaseTypesMap[std::make_pair(TREE_TYPE(Field), 0U)];
assert(oldTy);
TREE_TYPE(Field) = oldTy;
DECL_FIELD_BASE_REPLACED(Field) = 0;
}
}
}
}
/// DecodeStructFields - This method decodes the specified field, if it is a
/// FIELD_DECL, adding or updating the specified StructTypeConversionInfo to
/// reflect it. Return true if field is decoded correctly. Otherwise return
/// false.
bool TypeConverter::DecodeStructFields(tree Field,
StructTypeConversionInfo &Info) {
if (TREE_CODE(Field) != FIELD_DECL ||
TREE_CODE(DECL_FIELD_OFFSET(Field)) != INTEGER_CST)
return true;
// Handle bit-fields specially.
if (isBitfield(Field)) {
// If this field is forcing packed llvm struct then retry entire struct
// layout.
if (!Info.isPacked()) {
// Unnamed bitfield type does not contribute in struct alignment
// computations. Use packed llvm structure in such cases.
if (!DECL_NAME(Field))
return false;
// If this field is packed then the struct may need padding fields
// before this field.
if (DECL_PACKED(Field))
return false;
// If Field has user defined alignment and it does not match Ty alignment
// then convert to a packed struct and try again.
if (TYPE_USER_ALIGN(DECL_BIT_FIELD_TYPE(Field))) {
Type *Ty = ConvertType(getDeclaredType(Field));
if (TYPE_ALIGN(DECL_BIT_FIELD_TYPE(Field)) !=
8 * Info.getTypeAlignment(Ty))
return false;
}
}
DecodeStructBitField(Field, Info);
return true;
}
Info.allFieldsAreNotBitFields();
// Get the starting offset in the record.
uint64_t StartOffsetInBits = getFieldOffsetInBits(Field);
assert((StartOffsetInBits & 7) == 0 && "Non-bit-field has non-byte offset!");
uint64_t StartOffsetInBytes = StartOffsetInBits/8;
Type *Ty = ConvertType(getDeclaredType(Field));
// If this field is packed then the struct may need padding fields
// before this field.
if (DECL_PACKED(Field) && !Info.isPacked())
return false;
// Pop any previous elements out of the struct if they overlap with this one.
// This can happen when the C++ front-end overlaps fields with tail padding in
// C++ classes.
else if (!Info.ResizeLastElementIfOverlapsWith(StartOffsetInBytes, Field, Ty)) {
// LLVM disagrees as to where this field should go in the natural field
// ordering. Therefore convert to a packed struct and try again.
return false;
}
else if (TYPE_USER_ALIGN(TREE_TYPE(Field))
&& (unsigned)DECL_ALIGN(Field) != 8 * Info.getTypeAlignment(Ty)
&& !Info.isPacked()) {
// If Field has user defined alignment and it does not match Ty alignment
// then convert to a packed struct and try again.
return false;
} else
// At this point, we know that adding the element will happen at the right
// offset. Add it.
Info.addElement(Ty, StartOffsetInBytes, Info.getTypeSize(Ty));
return true;
}
/// DecodeStructBitField - This method decodes the specified bit-field, adding
/// or updating the specified StructTypeConversionInfo to reflect it.
///
/// Note that in general, we cannot produce a good covering of struct fields for
/// bitfields. As such, we only make sure that all bits in a struct that
/// correspond to a bitfield are represented in the LLVM struct with
/// (potentially multiple) integer fields of integer type. This ensures that
/// initialized globals with bitfields can have the initializers for the
/// bitfields specified.
void TypeConverter::DecodeStructBitField(tree_node *Field,
StructTypeConversionInfo &Info) {
unsigned FieldSizeInBits = TREE_INT_CST_LOW(DECL_SIZE(Field));
if (FieldSizeInBits == 0) // Ignore 'int:0', which just affects layout.
return;
// Get the starting offset in the record.
uint64_t StartOffsetInBits = getFieldOffsetInBits(Field);
uint64_t EndBitOffset = FieldSizeInBits+StartOffsetInBits;
// If the last inserted LLVM field completely contains this bitfield, just
// ignore this field.
if (!Info.Elements.empty()) {
uint64_t LastFieldBitOffset = Info.ElementOffsetInBytes.back()*8;
unsigned LastFieldBitSize = Info.ElementSizeInBytes.back()*8;
assert(LastFieldBitOffset <= StartOffsetInBits &&
"This bitfield isn't part of the last field!");
if (EndBitOffset <= LastFieldBitOffset+LastFieldBitSize &&
LastFieldBitOffset+LastFieldBitSize >= StartOffsetInBits) {
// Already contained in previous field. Update remaining extra bits that
// are available.
Info.extraBitsAvailable(Info.getEndUnallocatedByte()*8 - EndBitOffset);
return;
}
}
// Otherwise, this bitfield lives (potentially) partially in the preceeding
// field and in fields that exist after it. Add integer-typed fields to the
// LLVM struct such that there are no holes in the struct where the bitfield
// is: these holes would make it impossible to statically initialize a global
// of this type that has an initializer for the bitfield.
// We want the integer-typed fields as large as possible up to the machine
// word size. If there are more bitfields following this one, try to include
// them in the same field.
// Calculate the total number of bits in the continuous group of bitfields
// following this one. This is the number of bits that addNewBitField should
// try to include.
unsigned ExtraSizeInBits = 0;
tree LastBitField = 0;
for (tree f = TREE_CHAIN(Field); f; f = TREE_CHAIN(f)) {
if (TREE_CODE(f) != FIELD_DECL ||
TREE_CODE(DECL_FIELD_OFFSET(f)) != INTEGER_CST)
break;
if (isBitfield(f))
LastBitField = f;
else {
// We can use all this bits up to the next non-bitfield.
LastBitField = 0;
ExtraSizeInBits = getFieldOffsetInBits(f) - EndBitOffset;
break;
}
}
// Record ended in a bitfield? Use all of the last byte.
if (LastBitField)
ExtraSizeInBits = RoundUpToAlignment(getFieldOffsetInBits(LastBitField) +
TREE_INT_CST_LOW(DECL_SIZE(LastBitField)), 8) - EndBitOffset;
// Compute the number of bits that we need to add to this struct to cover
// this field.
uint64_t FirstUnallocatedByte = Info.getEndUnallocatedByte();
uint64_t StartOffsetFromByteBoundry = StartOffsetInBits & 7;
if (StartOffsetInBits < FirstUnallocatedByte*8) {
uint64_t AvailableBits = FirstUnallocatedByte * 8 - StartOffsetInBits;
// This field's starting point is already allocated.
if (StartOffsetFromByteBoundry == 0) {
// This field starts at byte boundry. Need to allocate space
// for additional bytes not yet allocated.
unsigned NumBitsToAdd = FieldSizeInBits - AvailableBits;
Info.addNewBitField(NumBitsToAdd, ExtraSizeInBits, FirstUnallocatedByte);
return;
}
// Otherwise, this field's starting point is inside previously used byte.
// This happens with Packed bit fields. In this case one LLVM Field is
// used to access previous field and current field.
unsigned prevFieldTypeSizeInBits =
Info.ElementSizeInBytes[Info.Elements.size() - 1] * 8;
unsigned NumBitsRequired = prevFieldTypeSizeInBits
+ (FieldSizeInBits - AvailableBits);
if (NumBitsRequired > 64) {
// Use bits from previous field.
NumBitsRequired = FieldSizeInBits - AvailableBits;
} else {
// If type used to access previous field is not large enough then
// remove previous field and insert new field that is large enough to
// hold both fields.
Info.RemoveFieldsAfter(Info.Elements.size() - 1);
for (unsigned idx = 0; idx < (prevFieldTypeSizeInBits/8); ++idx)
FirstUnallocatedByte--;
}
Info.addNewBitField(NumBitsRequired, ExtraSizeInBits, FirstUnallocatedByte);
// Do this after adding Field.
Info.lastFieldStartsAtNonByteBoundry(true);
return;
}
if (StartOffsetInBits > FirstUnallocatedByte*8) {
// If there is padding between the last field and the struct, insert
// explicit bytes into the field to represent it.
unsigned PadBytes = 0;
unsigned PadBits = 0;
if (StartOffsetFromByteBoundry != 0) {
// New field does not start at byte boundry.
PadBits = StartOffsetInBits - (FirstUnallocatedByte*8);
PadBytes = PadBits/8;
PadBits = PadBits - PadBytes*8;
} else
PadBytes = StartOffsetInBits/8-FirstUnallocatedByte;
if (PadBytes) {
Type *Pad = Type::getInt8Ty(Context);
if (PadBytes != 1)
Pad = ArrayType::get(Pad, PadBytes);
Info.addElement(Pad, FirstUnallocatedByte, PadBytes);
}
FirstUnallocatedByte = StartOffsetInBits/8;
// This field will use some of the bits from this PadBytes, if
// starting offset is not at byte boundry.
if (StartOffsetFromByteBoundry != 0)
FieldSizeInBits += PadBits;
}
// Now, Field starts at FirstUnallocatedByte and everything is aligned.
Info.addNewBitField(FieldSizeInBits, ExtraSizeInBits, FirstUnallocatedByte);
}
/// UnionHasOnlyZeroOffsets - Check if a union type has only members with
/// offsets that are zero, e.g., no Fortran equivalences.
static bool UnionHasOnlyZeroOffsets(tree type) {
for (tree Field = TYPE_FIELDS(type); Field; Field = TREE_CHAIN(Field)) {
if (TREE_CODE(Field) != FIELD_DECL) continue;
if (getFieldOffsetInBits(Field) != 0)
return false;
}
return true;
}
/// SelectUnionMember - Find the union member with the largest aligment. If
/// there are multiple types with the same alignment, select the one with
/// the largest size. If the type with max. align is smaller than other types,
/// then we will add padding later on anyway to match union size.
void TypeConverter::SelectUnionMember(tree type,
StructTypeConversionInfo &Info) {
Type *UnionTy = 0;
tree GccUnionTy = 0;
tree UnionField = 0;
unsigned MaxAlignSize = 0, MaxAlign = 0;
for (tree Field = TYPE_FIELDS(type); Field; Field = TREE_CHAIN(Field)) {
if (TREE_CODE(Field) != FIELD_DECL) continue;
assert(getFieldOffsetInBits(Field) == 0 && "Union with non-zero offset?");
// Skip fields that are known not to be present.
if (TREE_CODE(type) == QUAL_UNION_TYPE &&
integer_zerop(DECL_QUALIFIER(Field)))
continue;
tree TheGccTy = TREE_TYPE(Field);
// Skip zero-length fields; ConvertType refuses to construct a type
// of size 0.
if (DECL_SIZE(Field) &&
TREE_CODE(DECL_SIZE(Field)) == INTEGER_CST &&
TREE_INT_CST_LOW(DECL_SIZE(Field)) == 0)
continue;
Type *TheTy = ConvertType(TheGccTy);
unsigned Size = Info.getTypeSize(TheTy);
unsigned Align = Info.getTypeAlignment(TheTy);
adjustPaddingElement(GccUnionTy, TheGccTy);
// Select TheTy as union type if it is more aligned than any other. If
// more than one field achieves the maximum alignment then choose the
// biggest.
if (UnionTy == 0 || Align > MaxAlign ||
(Align == MaxAlign && Size > MaxAlignSize)) {
UnionTy = TheTy;
UnionField = Field;
GccUnionTy = TheGccTy;
MaxAlignSize = Size;
MaxAlign = Align;
}
// Skip remaining fields if this one is known to be present.
if (TREE_CODE(type) == QUAL_UNION_TYPE &&
integer_onep(DECL_QUALIFIER(Field)))
break;
}
if (UnionTy) { // Not an empty union.
if (8 * Info.getTypeAlignment(UnionTy) > TYPE_ALIGN(type))
Info.markAsPacked();
if (isBitfield(UnionField)) {
unsigned FieldSizeInBits = TREE_INT_CST_LOW(DECL_SIZE(UnionField));
Info.addNewBitField(FieldSizeInBits, 0, 0);
} else {
Info.allFieldsAreNotBitFields();
Info.addElement(UnionTy, 0, Info.getTypeSize(UnionTy));
}
}
}
/// ConvertRECORD - Convert a RECORD_TYPE, UNION_TYPE or QUAL_UNION_TYPE to
/// an LLVM type.
// A note on C++ virtual base class layout. Consider the following example:
// class A { public: int i0; };
// class B : public virtual A { public: int i1; };
// class C : public virtual A { public: int i2; };
// class D : public virtual B, public virtual C { public: int i3; };
//
// The TYPE nodes gcc builds for classes represent that class as it looks
// standing alone. Thus B is size 12 and looks like { vptr; i1; baseclass A; }
// However, this is not the layout used when that class is a base class for
// some other class, yet the same TYPE node is still used. D in the above has
// both a BINFO list entry and a FIELD that reference type B, but the virtual
// base class A within B is not allocated in that case; B-within-D is only
// size 8. The correct size is in the FIELD node (does not match the size
// in its child TYPE node.) The fields to be omitted from the child TYPE,
// as far as I can tell, are always the last ones; but also, there is a
// TYPE_DECL node sitting in the middle of the FIELD list separating virtual
// base classes from everything else.
//
// Similarly, a nonvirtual base class which has virtual base classes might
// not contain those virtual base classes when used as a nonvirtual base class.
// There is seemingly no way to detect this except for the size differential.
//
// For LLVM purposes, we build a new type for B-within-D that
// has the correct size and layout for that usage.
Type *TypeConverter::ConvertRECORD(tree type, tree orig_type) {
bool IsStruct = TREE_CODE(type) == RECORD_TYPE;
if (StructType *Ty = cast_or_null<StructType>(GET_TYPE_LLVM(type))) {
// If we already compiled this type, and if it was not a forward
// definition that is now defined, use the old type.
if (!Ty->isOpaque() || TYPE_SIZE(type) == 0)
return Ty;
} else {
// If we have no type for this, set it as an opaque named struct and
// continue.
SET_TYPE_LLVM(type, StructType::create(Context,
GetTypeName(IsStruct ? "struct." : "union.", orig_type)));
}
// If we have a forward declaration, we're done. Return the opaque type.
if (TYPE_SIZE(type) == 0)
return GET_TYPE_LLVM(type);
// If we're under a pointer under a struct, defer conversion of this type.
if (RecursionStatus == CS_StructPtr) {
StructsDeferred.push_back(type);
return GET_TYPE_LLVM(type);
}
ConversionStatus OldRecursionStatus = RecursionStatus;
RecursionStatus = CS_Struct;
StructTypeConversionInfo *Info =
new StructTypeConversionInfo(*TheTarget, TYPE_ALIGN(type) / 8,
TYPE_PACKED(type));
// Alter any fields that appear to represent base classes so their lists
// of fields bear some resemblance to reality. Also alter any fields that
// are less aligned than their type, as the type may not get tail padding
// in this case.
if (IsStruct)
FixUpFields(type);
// Workaround to get Fortran EQUIVALENCE working.
// TODO: Unify record and union logic and handle this optimally.
bool HasOnlyZeroOffsets = (!IsStruct && UnionHasOnlyZeroOffsets(type));
if (HasOnlyZeroOffsets) {
SelectUnionMember(type, *Info);
} else {
// Convert over all of the elements of the struct.
bool retryAsPackedStruct = false;
for (tree Field = TYPE_FIELDS(type); Field; Field = TREE_CHAIN(Field)) {
if (DecodeStructFields(Field, *Info) == false) {
retryAsPackedStruct = true;
break;
}
}
if (retryAsPackedStruct) {
delete Info;
Info = new StructTypeConversionInfo(*TheTarget, TYPE_ALIGN(type) / 8,
true);
for (tree Field = TYPE_FIELDS(type); Field; Field = TREE_CHAIN(Field)) {
if (DecodeStructFields(Field, *Info) == false) {
assert(0 && "Unable to decode struct fields.");
}
}
}
}
// Insert tail padding if the LLVM struct requires explicit tail padding to
// be the same size as the GCC struct or union. This handles, e.g., "{}" in
// C++, and cases where a union has larger alignment than the largest member
// does.
if (TYPE_SIZE(type) && TREE_CODE(TYPE_SIZE(type)) == INTEGER_CST) {
uint64_t GCCTypeSize = getInt64(TYPE_SIZE_UNIT(type), true);
uint64_t LLVMStructSize = Info->getSizeAsLLVMStruct();
if (LLVMStructSize > GCCTypeSize) {
Info->RemoveExtraBytes();
LLVMStructSize = Info->getSizeAsLLVMStruct();
}
if (LLVMStructSize != GCCTypeSize) {
assert(LLVMStructSize < GCCTypeSize &&
"LLVM type size doesn't match GCC type size!");
uint64_t LLVMLastElementEnd = Info->getNewElementByteOffset(1);
// If only one byte is needed then insert i8.
if (GCCTypeSize-LLVMLastElementEnd == 1)
Info->addElement(Type::getInt8Ty(Context), 1, 1);
else {
if (((GCCTypeSize-LLVMStructSize) % 4) == 0 &&
(Info->getAlignmentAsLLVMStruct() %
Info->getTypeAlignment(Type::getInt32Ty(Context))) == 0) {
// Insert array of i32.
unsigned Int32ArraySize = (GCCTypeSize-LLVMStructSize) / 4;
Type *PadTy =
ArrayType::get(Type::getInt32Ty(Context), Int32ArraySize);
Info->addElement(PadTy, GCCTypeSize - LLVMLastElementEnd,
Int32ArraySize, true /* Padding Element */);
} else {
Type *PadTy = ArrayType::get(Type::getInt8Ty(Context),
GCCTypeSize-LLVMStructSize);
Info->addElement(PadTy, GCCTypeSize - LLVMLastElementEnd,
GCCTypeSize - LLVMLastElementEnd,
true /* Padding Element */);
}
}
}
} else
Info->RemoveExtraBytes();
// Now that the LLVM struct is finalized, figure out a safe place to index to
// and set index values for each FieldDecl that doesn't start at a variable
// offset.
unsigned CurFieldNo = 0;
for (tree Field = TYPE_FIELDS(type); Field; Field = TREE_CHAIN(Field))
if (TREE_CODE(Field) == FIELD_DECL &&
TREE_CODE(DECL_FIELD_OFFSET(Field)) == INTEGER_CST) {
if (HasOnlyZeroOffsets) {
// Set the field idx to zero for all members of a union.
SET_LLVM_FIELD_INDEX(Field, 0);
} else {
uint64_t FieldOffsetInBits = getFieldOffsetInBits(Field);
tree FieldType = getDeclaredType(Field);
Type *FieldTy = ConvertType(FieldType);
// If this is a bitfield, we may want to adjust the FieldOffsetInBits
// to produce safe code. In particular, bitfields will be
// loaded/stored as their *declared* type, not the smallest integer
// type that contains them. As such, we need to respect the alignment
// of the declared type.
if (isBitfield(Field)) {
// If this is a bitfield, the declared type must be an integral type.
unsigned BitAlignment = Info->getTypeAlignment(FieldTy)*8;
FieldOffsetInBits &= ~(BitAlignment-1ULL);
// When we fix the field alignment, we must restart the FieldNo
// search because the FieldOffsetInBits can be lower than it was in
// the previous iteration.
CurFieldNo = 0;
// Skip 'int:0', which just affects layout.
if (integer_zerop(DECL_SIZE(Field)))
continue;
}
// Figure out if this field is zero bits wide, e.g. {} or [0 x int].
bool isZeroSizeField = FieldTy->isSized() &&
getTargetData().getTypeSizeInBits(FieldTy) == 0;
unsigned FieldNo =
Info->getLLVMFieldFor(FieldOffsetInBits, CurFieldNo, isZeroSizeField);
SET_LLVM_FIELD_INDEX(Field, FieldNo);
assert((isBitfield(Field) || FieldNo == ~0U ||
FieldOffsetInBits == 8*Info->ElementOffsetInBytes[FieldNo]) &&
"Wrong LLVM field offset!");
}
}
// Put the original gcc struct back the way it was; necessary to prevent the
// binfo-walking code in cp/class from getting confused.
if (IsStruct)
RestoreOriginalFields(type);
StructType *ResultTy = cast<StructType>(GET_TYPE_LLVM(type));
Info->fillInLLVMType((StructType*)ResultTy);
StructTypeInfoMap[type] = Info;
RecursionStatus = OldRecursionStatus;
// If we're popping back to a non-nested context, go ahead and convert any
// deferred record types.
if (RecursionStatus == CS_Normal) {
while (!StructsDeferred.empty())
ConvertType(StructsDeferred.pop_back_val());
}
return ResultTy;
}
/* LLVM LOCAL end (ENTIRE FILE!) */