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//===-- lib/MC/Disassembler.cpp - Disassembler Public C Interface ---------===//
// The LLVM Compiler Infrastructure
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
#include "Disassembler.h"
#include "llvm-c/Disassembler.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCDisassembler.h"
#include "llvm/MC/MCInst.h"
#include "llvm/MC/MCInstPrinter.h"
#include "llvm/MC/MCInstrInfo.h"
#include "llvm/MC/MCRegisterInfo.h"
#include "llvm/MC/MCSubtargetInfo.h"
#include "llvm/Support/MemoryObject.h"
#include "llvm/Support/TargetRegistry.h"
#include "llvm/Support/TargetSelect.h"
#include "llvm/Support/ErrorHandling.h"
namespace llvm {
class Target;
} // namespace llvm
using namespace llvm;
// LLVMCreateDisasm() creates a disassembler for the TripleName. Symbolic
// disassembly is supported by passing a block of information in the DisInfo
// parameter and specifying the TagType and callback functions as described in
// the header llvm-c/Disassembler.h . The pointer to the block and the
// functions can all be passed as NULL. If successful, this returns a
// disassembler context. If not, it returns NULL.
LLVMDisasmContextRef LLVMCreateDisasm(const char *TripleName, void *DisInfo,
int TagType, LLVMOpInfoCallback GetOpInfo,
LLVMSymbolLookupCallback SymbolLookUp) {
// Initialize targets and assembly printers/parsers.
// FIXME: Clients are responsible for initializing the targets. And this
// would be done by calling routines in "llvm-c/Target.h" which are static
// line functions. But the current use of LLVMCreateDisasm() is to dynamically
// load libLTO with dlopen() and then lookup the symbols using dlsym().
// And since these initialize routines are static that does not work which
// is why the call to them in this 'C' library API was added back.
// Get the target.
std::string Error;
const Target *TheTarget = TargetRegistry::lookupTarget(TripleName, Error);
assert(TheTarget && "Unable to create target!");
// Get the assembler info needed to setup the MCContext.
const MCAsmInfo *MAI = TheTarget->createMCAsmInfo(TripleName);
assert(MAI && "Unable to create target asm info!");
const MCInstrInfo *MII = TheTarget->createMCInstrInfo();
assert(MII && "Unable to create target instruction info!");
const MCRegisterInfo *MRI = TheTarget->createMCRegInfo(TripleName);
assert(MRI && "Unable to create target register info!");
// Package up features to be passed to target/subtarget
std::string FeaturesStr;
std::string CPU;
const MCSubtargetInfo *STI = TheTarget->createMCSubtargetInfo(TripleName, CPU,
assert(STI && "Unable to create subtarget info!");
// Set up the MCContext for creating symbols and MCExpr's.
MCContext *Ctx = new MCContext(*MAI, *MRI, 0);
assert(Ctx && "Unable to create MCContext!");
// Set up disassembler.
MCDisassembler *DisAsm = TheTarget->createMCDisassembler(*STI);
assert(DisAsm && "Unable to create disassembler!");
DisAsm->setupForSymbolicDisassembly(GetOpInfo, SymbolLookUp, DisInfo, Ctx);
// Set up the instruction printer.
int AsmPrinterVariant = MAI->getAssemblerDialect();
MCInstPrinter *IP = TheTarget->createMCInstPrinter(AsmPrinterVariant,
*MAI, *MII, *MRI, *STI);
assert(IP && "Unable to create instruction printer!");
LLVMDisasmContext *DC = new LLVMDisasmContext(TripleName, DisInfo, TagType,
GetOpInfo, SymbolLookUp,
TheTarget, MAI, MRI,
STI, MII, Ctx, DisAsm, IP);
assert(DC && "Allocation failure!");
return DC;
// LLVMDisasmDispose() disposes of the disassembler specified by the context.
void LLVMDisasmDispose(LLVMDisasmContextRef DCR){
LLVMDisasmContext *DC = (LLVMDisasmContext *)DCR;
delete DC;
namespace {
// The memory object created by LLVMDisasmInstruction().
class DisasmMemoryObject : public MemoryObject {
uint8_t *Bytes;
uint64_t Size;
uint64_t BasePC;
DisasmMemoryObject(uint8_t *bytes, uint64_t size, uint64_t basePC) :
Bytes(bytes), Size(size), BasePC(basePC) {}
uint64_t getBase() const { return BasePC; }
uint64_t getExtent() const { return Size; }
int readByte(uint64_t Addr, uint8_t *Byte) const {
if (Addr - BasePC >= Size)
return -1;
*Byte = Bytes[Addr - BasePC];
return 0;
} // end anonymous namespace
// LLVMDisasmInstruction() disassembles a single instruction using the
// disassembler context specified in the parameter DC. The bytes of the
// instruction are specified in the parameter Bytes, and contains at least
// BytesSize number of bytes. The instruction is at the address specified by
// the PC parameter. If a valid instruction can be disassembled its string is
// returned indirectly in OutString which whos size is specified in the
// parameter OutStringSize. This function returns the number of bytes in the
// instruction or zero if there was no valid instruction. If this function
// returns zero the caller will have to pick how many bytes they want to step
// over by printing a .byte, .long etc. to continue.
size_t LLVMDisasmInstruction(LLVMDisasmContextRef DCR, uint8_t *Bytes,
uint64_t BytesSize, uint64_t PC, char *OutString,
size_t OutStringSize){
LLVMDisasmContext *DC = (LLVMDisasmContext *)DCR;
// Wrap the pointer to the Bytes, BytesSize and PC in a MemoryObject.
DisasmMemoryObject MemoryObject(Bytes, BytesSize, PC);
uint64_t Size;
MCInst Inst;
const MCDisassembler *DisAsm = DC->getDisAsm();
MCInstPrinter *IP = DC->getIP();
MCDisassembler::DecodeStatus S;
S = DisAsm->getInstruction(Inst, Size, MemoryObject, PC,
/*REMOVE*/ nulls(), DC->CommentStream);
switch (S) {
case MCDisassembler::Fail:
case MCDisassembler::SoftFail:
// FIXME: Do something different for soft failure modes?
return 0;
case MCDisassembler::Success: {
StringRef Comments = DC->CommentsToEmit.str();
SmallVector<char, 64> InsnStr;
raw_svector_ostream OS(InsnStr);
IP->printInst(&Inst, OS, Comments);
// Tell the comment stream that the vector changed underneath it.
assert(OutStringSize != 0 && "Output buffer cannot be zero size");
size_t OutputSize = std::min(OutStringSize-1, InsnStr.size());
std::memcpy(OutString,, OutputSize);
OutString[OutputSize] = '\0'; // Terminate string.
return Size;
llvm_unreachable("Invalid DecodeStatus!");