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llvm-project/llvm/lib/CodeGen/AsmPrinter/AsmPrinterInlineAsm.cpp

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//===-- 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::DiagHandlerTy 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 {
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 a diagnostic handler, set it in SourceMgr.
LLVMContext &LLVMCtx = MMI->getModule()->getContext();
bool HasDiagHandler = false;
if (LLVMCtx.getDiagnosticHandler() != 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.getDiagnosticHandler();
DiagInfo.DiagContext = LLVMCtx.getDiagnosticContext();
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");
}
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).isMetadata()) {
Error = true;
} else {
unsigned OpFlags = MI->getOperand(OpNo).getImm();
++OpNo; // Skip over the ID number.
if (InlineAsm::isMemKind(OpFlags)) {
Error = AP->PrintAsmMemoryOperand(MI, OpNo, InlineAsmVariant,
/*Modifier*/ 0, OS);
} else {
Error = AP->PrintAsmOperand(MI, OpNo, InlineAsmVariant,
/*Modifier*/ 0, OS);
}
}
if (Error) {
std::string msg;
raw_string_ostream Msg(msg);
Msg << "invalid operand in inline asm: '" << AsmStr << "'";
MMI->getModule()->getContext().emitError(LocCookie, Msg.str());
}
break;
}
}
}
OS << "\n\t.att_syntax\n" << (char)0; // null terminate string.
}
static void EmitGCCInlineAsmStr(const char *AsmStr, const MachineInstr *MI,
MachineModuleInfo *MMI, int InlineAsmVariant,
int AsmPrinterVariant, AsmPrinter *AP,
unsigned LocCookie, raw_ostream &OS) {
int CurVariant = -1; // The number of the {.|.|.} region we are in.
const char *LastEmitted = AsmStr; // One past the last character emitted.
unsigned NumOperands = MI->getNumOperands();
OS << '\t';
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 != '$' && *LiteralEnd != '\n')
++LiteralEnd;
if (CurVariant == -1 || CurVariant == AsmPrinterVariant)
OS.write(LastEmitted, LiteralEnd-LastEmitted);
LastEmitted = LiteralEnd;
break;
}
case '\n':
++LastEmitted; // Consume newline character.
OS << '\n'; // Indent code with newline.
break;
case '$': {
++LastEmitted; // Consume '$' character.
bool Done = true;
// Handle escapes.
switch (*LastEmitted) {
default: Done = false; break;
case '$': // $$ -> $
if (CurVariant == -1 || CurVariant == AsmPrinterVariant)
OS << '$';
++LastEmitted; // Consume second '$' character.
break;
case '(': // $( -> same as GCC's { character.
++LastEmitted; // Consume '(' character.
if (CurVariant != -1)
report_fatal_error("Nested variants found in inline asm string: '" +
Twine(AsmStr) + "'");
CurVariant = 0; // We're in the first variant now.
break;
case '|':
++LastEmitted; // consume '|' character.
if (CurVariant == -1)
OS << '|'; // this is gcc's behavior for | outside a variant
else
++CurVariant; // We're in the next variant.
break;
case ')': // $) -> same as GCC's } char.
++LastEmitted; // consume ')' character.
if (CurVariant == -1)
OS << '}'; // this is gcc's behavior for } outside a variant
else
CurVariant = -1;
break;
}
if (Done) break;
bool HasCurlyBraces = false;
if (*LastEmitted == '{') { // ${variable}
++LastEmitted; // Consume '{' character.
HasCurlyBraces = true;
}
// If we have ${:foo}, then this is not a real operand reference, it is a
// "magic" string reference, just like in .td files. Arrange to call
// PrintSpecial.
if (HasCurlyBraces && *LastEmitted == ':') {
++LastEmitted;
const char *StrStart = LastEmitted;
const char *StrEnd = strchr(StrStart, '}');
if (StrEnd == 0)
report_fatal_error("Unterminated ${:foo} operand in inline asm"
" string: '" + Twine(AsmStr) + "'");
std::string Val(StrStart, StrEnd);
AP->PrintSpecial(MI, OS, Val.c_str());
LastEmitted = StrEnd+1;
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;
char Modifier[2] = { 0, 0 };
if (HasCurlyBraces) {
// If we have curly braces, check for a modifier character. This
// supports syntax like ${0:u}, which correspond to "%u0" in GCC asm.
if (*LastEmitted == ':') {
++LastEmitted; // Consume ':' character.
if (*LastEmitted == 0)
report_fatal_error("Bad ${:} expression in inline asm string: '" +
Twine(AsmStr) + "'");
Modifier[0] = *LastEmitted;
++LastEmitted; // Consume modifier character.
}
if (*LastEmitted != '}')
report_fatal_error("Bad ${} expression in inline asm string: '" +
Twine(AsmStr) + "'");
++LastEmitted; // Consume '}' character.
}
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!
if (CurVariant == -1 || CurVariant == AsmPrinterVariant) {
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).isMetadata()) {
Error = true;
} else {
unsigned OpFlags = MI->getOperand(OpNo).getImm();
++OpNo; // Skip over the ID number.
if (Modifier[0] == 'l') // labels are target independent
// FIXME: What if the operand isn't an MBB, report error?
OS << *MI->getOperand(OpNo).getMBB()->getSymbol();
else {
if (InlineAsm::isMemKind(OpFlags)) {
Error = AP->PrintAsmMemoryOperand(MI, OpNo, InlineAsmVariant,
Modifier[0] ? Modifier : 0,
OS);
} else {
Error = AP->PrintAsmOperand(MI, OpNo, InlineAsmVariant,
Modifier[0] ? Modifier : 0, OS);
}
}
}
if (Error) {
std::string msg;
raw_string_ostream Msg(msg);
Msg << "invalid operand in inline asm: '" << AsmStr << "'";
MMI->getModule()->getContext().emitError(LocCookie, Msg.str());
}
}
break;
}
}
}
OS << '\n' << (char)0; // null terminate string.
}
/// EmitInlineAsm - This method formats and emits the specified machine
/// instruction that is an inline asm.
void AsmPrinter::EmitInlineAsm(const MachineInstr *MI) const {
assert(MI->isInlineAsm() && "printInlineAsm only works on inline asms");
// Count the number of register definitions to find the asm string.
unsigned NumDefs = 0;
for (; MI->getOperand(NumDefs).isReg() && MI->getOperand(NumDefs).isDef();
++NumDefs)
assert(NumDefs != MI->getNumOperands()-2 && "No asm string?");
assert(MI->getOperand(NumDefs).isSymbol() && "No asm string?");
// Disassemble the AsmStr, printing out the literal pieces, the operands, etc.
const char *AsmStr = MI->getOperand(NumDefs).getSymbolName();
// If this asmstr is empty, just print the #APP/#NOAPP markers.
// These are useful to see where empty asm's wound up.
if (AsmStr[0] == 0) {
// Don't emit the comments if writing to a .o file.
if (!OutStreamer.hasRawTextSupport()) return;
OutStreamer.EmitRawText(Twine("\t")+MAI->getCommentString()+
MAI->getInlineAsmStart());
OutStreamer.EmitRawText(Twine("\t")+MAI->getCommentString()+
MAI->getInlineAsmEnd());
return;
}
// Emit the #APP start marker. This has to happen even if verbose-asm isn't
// enabled, so we use EmitRawText.
if (OutStreamer.hasRawTextSupport())
OutStreamer.EmitRawText(Twine("\t")+MAI->getCommentString()+
MAI->getInlineAsmStart());
// Get the !srcloc metadata node if we have it, and decode the loc cookie from
// it.
unsigned LocCookie = 0;
const MDNode *LocMD = 0;
for (unsigned i = MI->getNumOperands(); i != 0; --i) {
if (MI->getOperand(i-1).isMetadata() &&
(LocMD = MI->getOperand(i-1).getMetadata()) &&
LocMD->getNumOperands() != 0) {
if (const ConstantInt *CI = dyn_cast<ConstantInt>(LocMD->getOperand(0))) {
LocCookie = CI->getZExtValue();
break;
}
}
}
// Emit the inline asm to a temporary string so we can emit it through
// EmitInlineAsm.
SmallString<256> StringData;
raw_svector_ostream OS(StringData);
// The variant of the current asmprinter.
int AsmPrinterVariant = MAI->getAssemblerDialect();
InlineAsm::AsmDialect InlineAsmVariant = MI->getInlineAsmDialect();
AsmPrinter *AP = const_cast<AsmPrinter*>(this);
if (InlineAsmVariant == InlineAsm::AD_ATT)
EmitGCCInlineAsmStr(AsmStr, MI, MMI, InlineAsmVariant, AsmPrinterVariant,
AP, LocCookie, OS);
else
EmitMSInlineAsmStr(AsmStr, MI, MMI, InlineAsmVariant, AP, LocCookie, OS);
EmitInlineAsm(OS.str(), LocMD, MI->getInlineAsmDialect());
// Emit the #NOAPP end marker. This has to happen even if verbose-asm isn't
// enabled, so we use EmitRawText.
if (OutStreamer.hasRawTextSupport())
OutStreamer.EmitRawText(Twine("\t")+MAI->getCommentString()+
MAI->getInlineAsmEnd());
}
/// PrintSpecial - Print information related to the specified machine instr
/// that is independent of the operand, and may be independent of the instr
/// itself. This can be useful for portably encoding the comment character
/// or other bits of target-specific knowledge into the asmstrings. The
/// syntax used is ${:comment}. Targets can override this to add support
/// for their own strange codes.
void AsmPrinter::PrintSpecial(const MachineInstr *MI, raw_ostream &OS,
const char *Code) const {
if (!strcmp(Code, "private")) {
OS << MAI->getPrivateGlobalPrefix();
} else if (!strcmp(Code, "comment")) {
OS << MAI->getCommentString();
} else if (!strcmp(Code, "uid")) {
// Comparing the address of MI isn't sufficient, because machineinstrs may
// be allocated to the same address across functions.
// If this is a new LastFn instruction, bump the counter.
if (LastMI != MI || LastFn != getFunctionNumber()) {
++Counter;
LastMI = MI;
LastFn = getFunctionNumber();
}
OS << Counter;
} else {
std::string msg;
raw_string_ostream Msg(msg);
Msg << "Unknown special formatter '" << Code
<< "' for machine instr: " << *MI;
report_fatal_error(Msg.str());
}
}
/// PrintAsmOperand - Print the specified operand of MI, an INLINEASM
/// instruction, using the specified assembler variant. Targets should
/// override this to format as appropriate.
bool AsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
unsigned AsmVariant, const char *ExtraCode,
raw_ostream &O) {
// Does this asm operand have a single letter operand modifier?
if (ExtraCode && ExtraCode[0]) {
if (ExtraCode[1] != 0) return true; // Unknown modifier.
const MachineOperand &MO = MI->getOperand(OpNo);
switch (ExtraCode[0]) {
default:
return true; // Unknown modifier.
case 'c': // Substitute immediate value without immediate syntax
if (MO.getType() != MachineOperand::MO_Immediate)
return true;
O << MO.getImm();
return false;
case 'n': // Negate the immediate constant.
if (MO.getType() != MachineOperand::MO_Immediate)
return true;
O << -MO.getImm();
return false;
}
}
return true;
}
bool AsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI, unsigned OpNo,
unsigned AsmVariant,
const char *ExtraCode, raw_ostream &O) {
// Target doesn't support this yet!
return true;
}
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