path: root/lib/CodeGen/AsmPrinter/AsmPrinterInlineAsm.cpp

//===-- AsmPrinterInlineAsm.cpp - AsmPrinter Inline Asm Handling ----------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the inline assembler pieces of the AsmPrinter class.
//
//===----------------------------------------------------------------------===//

#define DEBUG_TYPE "asm-printer"
#include "llvm/CodeGen/AsmPrinter.h"
#include "llvm/ADT/OwningPtr.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/Twine.h"
#include "llvm/CodeGen/MachineBasicBlock.h"
#include "llvm/CodeGen/MachineModuleInfo.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/InlineAsm.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/Module.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/MC/MCSubtargetInfo.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/MC/MCTargetAsmParser.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/SourceMgr.h"
#include "llvm/Support/TargetRegistry.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetMachine.h"
using namespace llvm;

namespace {
  struct SrcMgrDiagInfo {
    const MDNode *LocInfo;
    LLVMContext::InlineAsmDiagHandlerTy DiagHandler;
    void *DiagContext;
  };
}

/// srcMgrDiagHandler - This callback is invoked when the SourceMgr for an
/// inline asm has an error in it.  diagInfo is a pointer to the SrcMgrDiagInfo
/// struct above.
static void srcMgrDiagHandler(const SMDiagnostic &Diag, void *diagInfo) {
  SrcMgrDiagInfo *DiagInfo = static_cast<SrcMgrDiagInfo *>(diagInfo);
  assert(DiagInfo && "Diagnostic context not passed down?");

  // If the inline asm had metadata associated with it, pull out a location
  // cookie corresponding to which line the error occurred on.
  unsigned LocCookie = 0;
  if (const MDNode *LocInfo = DiagInfo->LocInfo) {
    unsigned ErrorLine = Diag.getLineNo()-1;
    if (ErrorLine >= LocInfo->getNumOperands())
      ErrorLine = 0;

    if (LocInfo->getNumOperands() != 0)
      if (const ConstantInt *CI =
          dyn_cast<ConstantInt>(LocInfo->getOperand(ErrorLine)))
        LocCookie = CI->getZExtValue();
  }

  DiagInfo->DiagHandler(Diag, DiagInfo->DiagContext, LocCookie);
}

/// EmitInlineAsm - Emit a blob of inline asm to the output streamer.
void AsmPrinter::EmitInlineAsm(StringRef Str, const MDNode *LocMDNode,
                               InlineAsm::AsmDialect Dialect) const {
#if defined(__native_client__)
  // Prune the generic AsmParser bits from the in-browser translator.
  // This is normally used to parse inline asm (see createMCAsmParser below).
  return;
#else
  assert(!Str.empty() && "Can't emit empty inline asm block");

  // Remember if the buffer is nul terminated or not so we can avoid a copy.
  bool isNullTerminated = Str.back() == 0;
  if (isNullTerminated)
    Str = Str.substr(0, Str.size()-1);

  // If the output streamer is actually a .s file, just emit the blob textually.
  // This is useful in case the asm parser doesn't handle something but the
  // system assembler does.
  if (OutStreamer.hasRawTextSupport()) {
    OutStreamer.EmitRawText(Str);
    return;
  }

  SourceMgr SrcMgr;
  SrcMgrDiagInfo DiagInfo;

  // If the current LLVMContext has an inline asm handler, set it in SourceMgr.
  LLVMContext &LLVMCtx = MMI->getModule()->getContext();
  bool HasDiagHandler = false;
  if (LLVMCtx.getInlineAsmDiagnosticHandler() != 0) {
    // If the source manager has an issue, we arrange for srcMgrDiagHandler
    // to be invoked, getting DiagInfo passed into it.
    DiagInfo.LocInfo = LocMDNode;
    DiagInfo.DiagHandler = LLVMCtx.getInlineAsmDiagnosticHandler();
    DiagInfo.DiagContext = LLVMCtx.getInlineAsmDiagnosticContext();
    SrcMgr.setDiagHandler(srcMgrDiagHandler, &DiagInfo);
    HasDiagHandler = true;
  }

  MemoryBuffer *Buffer;
  if (isNullTerminated)
    Buffer = MemoryBuffer::getMemBuffer(Str, "<inline asm>");
  else
    Buffer = MemoryBuffer::getMemBufferCopy(Str, "<inline asm>");

  // Tell SrcMgr about this buffer, it takes ownership of the buffer.
  SrcMgr.AddNewSourceBuffer(Buffer, SMLoc());

  OwningPtr<MCAsmParser> Parser(createMCAsmParser(SrcMgr,
                                                  OutContext, OutStreamer,
                                                  *MAI));

  // FIXME: It would be nice if we can avoid createing a new instance of
  // MCSubtargetInfo here given TargetSubtargetInfo is available. However,
  // we have to watch out for asm directives which can change subtarget
  // state. e.g. .code 16, .code 32.
  OwningPtr<MCSubtargetInfo>
    STI(TM.getTarget().createMCSubtargetInfo(TM.getTargetTriple(),
                                             TM.getTargetCPU(),
                                             TM.getTargetFeatureString()));
  OwningPtr<MCTargetAsmParser>
    TAP(TM.getTarget().createMCAsmParser(*STI, *Parser));
  if (!TAP)
    report_fatal_error("Inline asm not supported by this streamer because"
                       " we don't have an asm parser for this target\n");
  Parser->setAssemblerDialect(Dialect);
  Parser->setTargetParser(*TAP.get());

  // Don't implicitly switch to the text section before the asm.
  int Res = Parser->Run(/*NoInitialTextSection*/ true,
                        /*NoFinalize*/ true);
  if (Res && !HasDiagHandler)
    report_fatal_error("Error parsing inline asm\n");
#endif  // defined(__native_client__)
}

static void EmitMSInlineAsmStr(const char *AsmStr, const MachineInstr *MI,
                               MachineModuleInfo *MMI, int InlineAsmVariant,
                               AsmPrinter *AP, unsigned LocCookie,
                               raw_ostream &OS) {
  // Switch to the inline assembly variant.
  OS << "\t.intel_syntax\n\t";

  const char *LastEmitted = AsmStr; // One past the last character emitted.
  unsigned NumOperands = MI->getNumOperands();

  while (*LastEmitted) {
    switch (*LastEmitted) {
    default: {
      // Not a special case, emit the string section literally.
      const char *LiteralEnd = LastEmitted+1;
      while (*LiteralEnd && *LiteralEnd != '{' && *LiteralEnd != '|' &&
             *LiteralEnd != '}' && *LiteralEnd != '$' && *LiteralEnd != '\n')
        ++LiteralEnd;

      OS.write(LastEmitted, LiteralEnd-LastEmitted);
      LastEmitted = LiteralEnd;
      break;
    }
    case '\n':
      ++LastEmitted;   // Consume newline character.
      OS << '\n';      // Indent code with newline.
      break;
    case '$': {
      ++LastEmitted;   // Consume '$' character.
      bool Done = true;

      // Handle escapes.
      switch (*LastEmitted) {
      default: Done = false; break;
      case '$':
        ++LastEmitted;  // Consume second '$' character.
        break;
      }
      if (Done) break;

      const char *IDStart = LastEmitted;
      const char *IDEnd = IDStart;
      while (*IDEnd >= '0' && *IDEnd <= '9') ++IDEnd;

      unsigned Val;
      if (StringRef(IDStart, IDEnd-IDStart).getAsInteger(10, Val))
        report_fatal_error("Bad $ operand number in inline asm string: '" +
                           Twine(AsmStr) + "'");
      LastEmitted = IDEnd;

      if (Val >= NumOperands-1)
        report_fatal_error("Invalid $ operand number in inline asm string: '" +
                           Twine(AsmStr) + "'");

      // Okay, we finally have a value number.  Ask the target to print this
      // operand!
      unsigned OpNo = InlineAsm::MIOp_FirstOperand;

      bool Error = false;

      // Scan to find the machine operand number for the operand.
      for (; Val; --Val) {
        if (OpNo >= MI->getNumOperands()) break;
        unsigned OpFlags = MI->getOperand(OpNo).getImm();
        OpNo += InlineAsm::getNumOperandRegisters(OpFlags) + 1;
      }

      // We may have a location metadata attached to the end of the
      // instruction, and at no point should see metadata at any
      // other point while processing. It's an error if so.
      if (OpNo >= MI->getNumOperands() ||
          MI->getOperand(OpNo