1 files changed, 171 insertions, 0 deletions
diff --git a/lib/MC/MCDisassembler/Disassembler.cpp b/lib/MC/MCDisassembler/Disassembler.cpp
new file mode 100644
index 000000000000..ced57e8ca2de
--- /dev/null
+++ b/lib/MC/MCDisassembler/Disassembler.cpp
@@ -0,0 +1,171 @@
+//===-- lib/MC/Disassembler.cpp - Disassembler Public C Interface -*- C -*-===//
+//
+//                     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 <stdio.h>
+#include "llvm-c/Disassembler.h"
+
+#include <string>
+#include "llvm/MC/MCAsmInfo.h"
+#include "llvm/MC/MCDisassembler.h"
+#include "llvm/MC/MCInst.h"
+#include "llvm/MC/MCInstPrinter.h"
+#include "llvm/MC/MCContext.h"
+#include "llvm/Target/TargetRegistry.h"
+#include "llvm/Target/TargetAsmInfo.h"  // FIXME.
+#include "llvm/Target/TargetMachine.h"  // FIXME.
+#include "llvm/Target/TargetSelect.h"
+#include "llvm/Support/MemoryObject.h"
+
+namespace llvm {
+class Target;
+} // namespace llvm
+using namespace llvm;
+
+#ifdef __cplusplus
+extern "C" {
+#endif // __cplusplus
+
+//
+// LLVMCreateDisasm() creates a disassembler for the TripleName.  Symbolic
+// disassembly is supported by passing a block of information in the DisInfo
+// parameter and specifing the TagType and call back 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.
+  llvm::InitializeAllTargetInfos();
+  // FIXME: We shouldn't need to initialize the Target(Machine)s.
+  llvm::InitializeAllTargets();
+  llvm::InitializeAllAsmPrinters();
+  llvm::InitializeAllAsmParsers();
+  llvm::InitializeAllDisassemblers();
+
+  // 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->createAsmInfo(TripleName);
+  assert(MAI && "Unable to create target asm info!");
+
+  // Package up features to be passed to target/subtarget
+  std::string FeaturesStr;
+
+  // FIXME: We shouldn't need to do this (and link in codegen).
+  //        When we split this out, we should do it in a way that makes
+  //        it straightforward to switch subtargets on the fly.
+  TargetMachine *TM = TheTarget->createTargetMachine(TripleName, FeaturesStr);
+  assert(TM && "Unable to create target machine!");
+
+  // Get the target assembler info needed to setup the context.
+  const TargetAsmInfo *tai = new TargetAsmInfo(*TM);
+  assert(tai && "Unable to create target assembler!");
+
+  // Set up the MCContext for creating symbols and MCExpr's.
+  MCContext *Ctx = new MCContext(*MAI, tai);
+  assert(Ctx && "Unable to create MCContext!");
+
+  // Set up disassembler.
+  MCDisassembler *DisAsm = TheTarget->createMCDisassembler();
+  assert(DisAsm && "Unable to create disassembler!");
+  DisAsm->setupForSymbolicDisassembly(GetOpInfo, DisInfo, Ctx);
+
+  // Set up the instruction printer.
+  int AsmPrinterVariant = MAI->getAssemblerDialect();
+  MCInstPrinter *IP = TheTarget->createMCInstPrinter(*TM, AsmPrinterVariant,
+                                                     *MAI);
+  assert(IP && "Unable to create instruction printer!");
+
+  LLVMDisasmContext *DC = new LLVMDisasmContext(TripleName, DisInfo, TagType,
+                                                GetOpInfo, SymbolLookUp,
+                                                TheTarget, MAI, TM, tai, 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 {
+private:
+  uint8_t *Bytes;
+  uint64_t Size;
+  uint64_t BasePC;
+public:
+  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;
+  }
+};
+} // 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();
+  if (!DisAsm->getInstruction(Inst, Size, MemoryObject, PC, /*REMOVE*/ nulls()))
+    return 0;
+
+  std::string InsnStr;
+  raw_string_ostream OS(InsnStr);
+  IP->printInst(&Inst, OS);
+  OS.flush();
+
+  size_t OutputSize = std::min(OutStringSize-1, InsnStr.size());
+  std::memcpy(OutString, InsnStr.data(), OutputSize);
+  OutString[OutputSize] = '\0'; // Terminate string.
+
+  return Size;
+}
+
+#ifdef __cplusplus
+}
+#endif // __cplusplus