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//===-- llvm/CodeGen/MachineModuleInfo.h ------------------------*- C++ -*-===//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
// Collect meta information for a module. This information should be in a
// neutral form that can be used by different debugging and exception handling
// schemes.
// The organization of information is primarily clustered around the source
// compile units. The main exception is source line correspondence where
// inlining may interleave code from various compile units.
// The following information can be retrieved from the MachineModuleInfo.
// -- Source directories - Directories are uniqued based on their canonical
// string and assigned a sequential numeric ID (base 1.)
// -- Source files - Files are also uniqued based on their name and directory
// ID. A file ID is sequential number (base 1.)
// -- Source line correspondence - A vector of file ID, line#, column# triples.
// A DEBUG_LOCATION instruction is generated by the DAG Legalizer
// corresponding to each entry in the source line list. This allows a debug
// emitter to generate labels referenced by debug information tables.
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/PointerIntPair.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/Pass.h"
#include <memory>
#include <utility>
#include <vector>
namespace llvm {
class BasicBlock;
class CallInst;
class Function;
class LLVMTargetMachine;
class MMIAddrLabelMap;
class MachineFunction;
class Module;
/// This class can be derived from and used by targets to hold private
/// target-specific information for each Module. Objects of type are
/// accessed/created with MMI::getInfo and destroyed when the MachineModuleInfo
/// is destroyed.
class MachineModuleInfoImpl {
using StubValueTy = PointerIntPair<MCSymbol *, 1, bool>;
using SymbolListTy = std::vector<std::pair<MCSymbol *, StubValueTy>>;
virtual ~MachineModuleInfoImpl();
/// Return the entries from a DenseMap in a deterministic sorted orer.
/// Clears the map.
static SymbolListTy getSortedStubs(DenseMap<MCSymbol*, StubValueTy>&);
/// This class contains meta information specific to a module. Queries can be
/// made by different debugging and exception handling schemes and reformated
/// for specific use.
class MachineModuleInfo : public ImmutablePass {
const LLVMTargetMachine &TM;
/// This is the MCContext used for the entire code generator.
MCContext Context;
/// This is the LLVM Module being worked on.
const Module *TheModule;
/// This is the object-file-format-specific implementation of
/// MachineModuleInfoImpl, which lets targets accumulate whatever info they
/// want.
MachineModuleInfoImpl *ObjFileMMI;
/// \name Exception Handling
/// \{
/// Vector of all personality functions ever seen. Used to emit common EH
/// frames.
std::vector<const Function *> Personalities;
/// The current call site index being processed, if any. 0 if none.
unsigned CurCallSite;
/// \}
/// This map keeps track of which symbol is being used for the specified
/// basic block's address of label.
MMIAddrLabelMap *AddrLabelSymbols;
// TODO: Ideally, what we'd like is to have a switch that allows emitting
// synchronous (precise at call-sites only) CFA into .eh_frame. However,
// even under this switch, we'd like .debug_frame to be precise when using
// -g. At this moment, there's no way to specify that some CFI directives
// go into .eh_frame only, while others go into .debug_frame only.
/// True if debugging information is available in this module.
bool DbgInfoAvailable;
/// True if this module is being built for windows/msvc, and uses floating
/// point. This is used to emit an undefined reference to _fltused.
bool UsesMSVCFloatingPoint;
/// True if the module calls the __morestack function indirectly, as is
/// required under the large code model on x86. This is used to emit
/// a definition of a symbol, __morestack_addr, containing the address. See
/// comments in lib/Target/X86/X86FrameLowering.cpp for more details.
bool UsesMorestackAddr;
/// True if the module contains split-stack functions. This is used to
/// emit .note.GNU-split-stack section as required by the linker for
/// special handling split-stack function calling no-split-stack function.
bool HasSplitStack;
/// True if the module contains no-split-stack functions. This is used to
/// emit .note.GNU-no-split-stack section when it also contains split-stack
/// functions.
bool HasNosplitStack;
/// Maps IR Functions to their corresponding MachineFunctions.
DenseMap<const Function*, std::unique_ptr<MachineFunction>> MachineFunctions;
/// Next unique number available for a MachineFunction.
unsigned NextFnNum = 0;
const Function *LastRequest = nullptr; ///< Used for shortcut/cache.
MachineFunction *LastResult = nullptr; ///< Used for shortcut/cache.
static char ID; // Pass identification, replacement for typeid
explicit MachineModuleInfo(const LLVMTargetMachine *TM = nullptr);
~MachineModuleInfo() override;
// Initialization and Finalization
bool doInitialization(Module &) override;
bool doFinalization(Module &) override;
const LLVMTargetMachine &getTarget() const { return TM; }
const MCContext &getContext() const { return Context; }
MCContext &getContext() { return Context; }
const Module *getModule() const { return TheModule; }
/// Returns the MachineFunction constructed for the IR function \p F.
/// Creates a new MachineFunction if none exists yet.
MachineFunction &getOrCreateMachineFunction(const Function &F);
/// \bried Returns the MachineFunction associated to IR function \p F if there
/// is one, otherwise nullptr.
MachineFunction *getMachineFunction(const Function &F) const;
/// Delete the MachineFunction \p MF and reset the link in the IR Function to
/// Machine Function map.
void deleteMachineFunctionFor(Function &F);
/// Keep track of various per-function pieces of information for backends
/// that would like to do so.
template<typename Ty>
Ty &getObjFileInfo() {
if (ObjFileMMI == nullptr)
ObjFileMMI = new Ty(*this);
return *static_cast<Ty*>(ObjFileMMI);
template<typename Ty>
const Ty &getObjFileInfo() const {
return const_cast<MachineModuleInfo*>(this)->getObjFileInfo<Ty>();
/// Returns true if valid debug info is present.
bool hasDebugInfo() const { return DbgInfoAvailable; }
void setDebugInfoAvailability(bool avail) { DbgInfoAvailable = avail; }
bool usesMSVCFloatingPoint() const { return UsesMSVCFloatingPoint; }
void setUsesMSVCFloatingPoint(bool b) { UsesMSVCFloatingPoint = b; }
bool usesMorestackAddr() const {
return UsesMorestackAddr;
void setUsesMorestackAddr(bool b) {
UsesMorestackAddr = b;
bool hasSplitStack() const {
return HasSplitStack;
void setHasSplitStack(bool b) {
HasSplitStack = b;
bool hasNosplitStack() const {
return HasNosplitStack;
void setHasNosplitStack(bool b) {
HasNosplitStack = b;
/// Return the symbol to be used for the specified basic block when its
/// address is taken. This cannot be its normal LBB label because the block
/// may be accessed outside its containing function.
MCSymbol *getAddrLabelSymbol(const BasicBlock *BB) {
return getAddrLabelSymbolToEmit(BB).front();
/// Return the symbol to be used for the specified basic block when its
/// address is taken. If other blocks were RAUW'd to this one, we may have
/// to emit them as well, return the whole set.
ArrayRef<MCSymbol *> getAddrLabelSymbolToEmit(const BasicBlock *BB);
/// If the specified function has had any references to address-taken blocks
/// generated, but the block got deleted, return the symbol now so we can
/// emit it. This prevents emitting a reference to a symbol that has no
/// definition.
void takeDeletedSymbolsForFunction(const Function *F,
std::vector<MCSymbol*> &Result);
/// \name Exception Handling
/// \{
/// Set the call site currently being processed.
void setCurrentCallSite(unsigned Site) { CurCallSite = Site; }
/// Get the call site currently being processed, if any. return zero if
/// none.
unsigned getCurrentCallSite() { return CurCallSite; }
/// Provide the personality function for the exception information.
void addPersonality(const Function *Personality);
/// Return array of personality functions ever seen.
const std::vector<const Function *>& getPersonalities() const {
return Personalities;
/// \}
}; // End class MachineModuleInfo
} // end namespace llvm