1//===-- lib/MC/Disassembler.cpp - Disassembler Public C Interface ---------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9
10#include "Disassembler.h"
11#include "llvm-c/Disassembler.h"
12#include "llvm/MC/MCAsmInfo.h"
13#include "llvm/MC/MCContext.h"
14#include "llvm/MC/MCDisassembler.h"
15#include "llvm/MC/MCInst.h"
16#include "llvm/MC/MCInstPrinter.h"
17#include "llvm/MC/MCInstrInfo.h"
18#include "llvm/MC/MCRegisterInfo.h"
19#include "llvm/MC/MCSubtargetInfo.h"
20#include "llvm/Support/ErrorHandling.h"
21#include "llvm/Support/MemoryObject.h"
22#include "llvm/Support/TargetRegistry.h"
23
24namespace llvm {
25class Target;
26} // namespace llvm
27using namespace llvm;
28
29// LLVMCreateDisasm() creates a disassembler for the TripleName.  Symbolic
30// disassembly is supported by passing a block of information in the DisInfo
31// parameter and specifying the TagType and callback functions as described in
32// the header llvm-c/Disassembler.h .  The pointer to the block and the
33// functions can all be passed as NULL.  If successful, this returns a
34// disassembler context.  If not, it returns NULL.
35//
36LLVMDisasmContextRef LLVMCreateDisasmCPU(const char *Triple, const char *CPU,
37                                         void *DisInfo, int TagType,
38                                         LLVMOpInfoCallback GetOpInfo,
39                                         LLVMSymbolLookupCallback SymbolLookUp){
40  // Get the target.
41  std::string Error;
42  const Target *TheTarget = TargetRegistry::lookupTarget(Triple, Error);
43  assert(TheTarget && "Unable to create target!");
44
45  // Get the assembler info needed to setup the MCContext.
46  const MCAsmInfo *MAI = TheTarget->createMCAsmInfo(Triple);
47  if (!MAI)
48    return 0;
49
50  const MCInstrInfo *MII = TheTarget->createMCInstrInfo();
51  if (!MII)
52    return 0;
53
54  const MCRegisterInfo *MRI = TheTarget->createMCRegInfo(Triple);
55  if (!MRI)
56    return 0;
57
58  // Package up features to be passed to target/subtarget
59  std::string FeaturesStr;
60
61  const MCSubtargetInfo *STI = TheTarget->createMCSubtargetInfo(Triple, CPU,
62                                                                FeaturesStr);
63  if (!STI)
64    return 0;
65
66  // Set up the MCContext for creating symbols and MCExpr's.
67  MCContext *Ctx = new MCContext(*MAI, *MRI, 0);
68  if (!Ctx)
69    return 0;
70
71  // Set up disassembler.
72  MCDisassembler *DisAsm = TheTarget->createMCDisassembler(*STI);
73  if (!DisAsm)
74    return 0;
75  DisAsm->setupForSymbolicDisassembly(GetOpInfo, SymbolLookUp, DisInfo, Ctx);
76
77  // Set up the instruction printer.
78  int AsmPrinterVariant = MAI->getAssemblerDialect();
79  MCInstPrinter *IP = TheTarget->createMCInstPrinter(AsmPrinterVariant,
80                                                     *MAI, *MII, *MRI, *STI);
81  if (!IP)
82    return 0;
83
84  LLVMDisasmContext *DC = new LLVMDisasmContext(Triple, DisInfo, TagType,
85                                                GetOpInfo, SymbolLookUp,
86                                                TheTarget, MAI, MRI,
87                                                STI, MII, Ctx, DisAsm, IP);
88  if (!DC)
89    return 0;
90
91  return DC;
92}
93
94LLVMDisasmContextRef LLVMCreateDisasm(const char *Triple, void *DisInfo,
95                                      int TagType, LLVMOpInfoCallback GetOpInfo,
96                                      LLVMSymbolLookupCallback SymbolLookUp) {
97  return LLVMCreateDisasmCPU(Triple, "", DisInfo, TagType, GetOpInfo,
98                             SymbolLookUp);
99}
100
101//
102// LLVMDisasmDispose() disposes of the disassembler specified by the context.
103//
104void LLVMDisasmDispose(LLVMDisasmContextRef DCR){
105  LLVMDisasmContext *DC = (LLVMDisasmContext *)DCR;
106  delete DC;
107}
108
109namespace {
110//
111// The memory object created by LLVMDisasmInstruction().
112//
113class DisasmMemoryObject : public MemoryObject {
114  uint8_t *Bytes;
115  uint64_t Size;
116  uint64_t BasePC;
117public:
118  DisasmMemoryObject(uint8_t *bytes, uint64_t size, uint64_t basePC) :
119                     Bytes(bytes), Size(size), BasePC(basePC) {}
120
121  uint64_t getBase() const { return BasePC; }
122  uint64_t getExtent() const { return Size; }
123
124  int readByte(uint64_t Addr, uint8_t *Byte) const {
125    if (Addr - BasePC >= Size)
126      return -1;
127    *Byte = Bytes[Addr - BasePC];
128    return 0;
129  }
130};
131} // end anonymous namespace
132
133//
134// LLVMDisasmInstruction() disassembles a single instruction using the
135// disassembler context specified in the parameter DC.  The bytes of the
136// instruction are specified in the parameter Bytes, and contains at least
137// BytesSize number of bytes.  The instruction is at the address specified by
138// the PC parameter.  If a valid instruction can be disassembled its string is
139// returned indirectly in OutString which whos size is specified in the
140// parameter OutStringSize.  This function returns the number of bytes in the
141// instruction or zero if there was no valid instruction.  If this function
142// returns zero the caller will have to pick how many bytes they want to step
143// over by printing a .byte, .long etc. to continue.
144//
145size_t LLVMDisasmInstruction(LLVMDisasmContextRef DCR, uint8_t *Bytes,
146                             uint64_t BytesSize, uint64_t PC, char *OutString,
147                             size_t OutStringSize){
148  LLVMDisasmContext *DC = (LLVMDisasmContext *)DCR;
149  // Wrap the pointer to the Bytes, BytesSize and PC in a MemoryObject.
150  DisasmMemoryObject MemoryObject(Bytes, BytesSize, PC);
151
152  uint64_t Size;
153  MCInst Inst;
154  const MCDisassembler *DisAsm = DC->getDisAsm();
155  MCInstPrinter *IP = DC->getIP();
156  MCDisassembler::DecodeStatus S;
157  S = DisAsm->getInstruction(Inst, Size, MemoryObject, PC,
158                             /*REMOVE*/ nulls(), DC->CommentStream);
159  switch (S) {
160  case MCDisassembler::Fail:
161  case MCDisassembler::SoftFail:
162    // FIXME: Do something different for soft failure modes?
163    return 0;
164
165  case MCDisassembler::Success: {
166    DC->CommentStream.flush();
167    StringRef Comments = DC->CommentsToEmit.str();
168
169    SmallVector<char, 64> InsnStr;
170    raw_svector_ostream OS(InsnStr);
171    IP->printInst(&Inst, OS, Comments);
172    OS.flush();
173
174    // Tell the comment stream that the vector changed underneath it.
175    DC->CommentsToEmit.clear();
176    DC->CommentStream.resync();
177
178    assert(OutStringSize != 0 && "Output buffer cannot be zero size");
179    size_t OutputSize = std::min(OutStringSize-1, InsnStr.size());
180    std::memcpy(OutString, InsnStr.data(), OutputSize);
181    OutString[OutputSize] = '\0'; // Terminate string.
182
183    return Size;
184  }
185  }
186  llvm_unreachable("Invalid DecodeStatus!");
187}
188
189//
190// LLVMSetDisasmOptions() sets the disassembler's options.  It returns 1 if it
191// can set all the Options and 0 otherwise.
192//
193int LLVMSetDisasmOptions(LLVMDisasmContextRef DCR, uint64_t Options){
194  if (Options & LLVMDisassembler_Option_UseMarkup){
195      LLVMDisasmContext *DC = (LLVMDisasmContext *)DCR;
196      MCInstPrinter *IP = DC->getIP();
197      IP->setUseMarkup(1);
198      Options &= ~LLVMDisassembler_Option_UseMarkup;
199  }
200  if (Options & LLVMDisassembler_Option_PrintImmHex){
201      LLVMDisasmContext *DC = (LLVMDisasmContext *)DCR;
202      MCInstPrinter *IP = DC->getIP();
203      IP->setPrintImmHex(1);
204      Options &= ~LLVMDisassembler_Option_PrintImmHex;
205  }
206  if (Options & LLVMDisassembler_Option_AsmPrinterVariant){
207      LLVMDisasmContext *DC = (LLVMDisasmContext *)DCR;
208      // Try to set up the new instruction printer.
209      const MCAsmInfo *MAI = DC->getAsmInfo();
210      const MCInstrInfo *MII = DC->getInstrInfo();
211      const MCRegisterInfo *MRI = DC->getRegisterInfo();
212      const MCSubtargetInfo *STI = DC->getSubtargetInfo();
213      int AsmPrinterVariant = MAI->getAssemblerDialect();
214      AsmPrinterVariant = AsmPrinterVariant == 0 ? 1 : 0;
215      MCInstPrinter *IP = DC->getTarget()->createMCInstPrinter(
216          AsmPrinterVariant, *MAI, *MII, *MRI, *STI);
217      if (IP) {
218        DC->setIP(IP);
219        Options &= ~LLVMDisassembler_Option_AsmPrinterVariant;
220      }
221  }
222  return (Options == 0);
223}
224