llvm-6502/lib/CodeGen/AsmPrinter/AsmPrinterInlineAsm.cpp
Eric Christopher aa206ffa6b In erroneous inline assembly we could mistakenly try to access the
metadata operand as an actual operand, leading to an assert. Error
out in this case.

rdar://11007633

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153234 91177308-0d34-0410-b5e6-96231b3b80d8
2012-03-22 01:33:51 +00:00

425 lines
16 KiB
C++

//===-- 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/Constants.h"
#include "llvm/InlineAsm.h"
#include "llvm/LLVMContext.h"
#include "llvm/Module.h"
#include "llvm/CodeGen/MachineBasicBlock.h"
#include "llvm/CodeGen/MachineModuleInfo.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/Target/TargetMachine.h"
#include "llvm/ADT/OwningPtr.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/Twine.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"
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) 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 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->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");
}
/// 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");
unsigned NumOperands = MI->getNumOperands();
// 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 != NumOperands-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);
OS << '\t';
// The variant of the current asmprinter.
int AsmPrinterVariant = MAI->getAssemblerDialect();
int CurVariant = -1; // The number of the {.|.|.} region we are in.
const char *LastEmitted = AsmStr; // One past the last character emitted.
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);
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 {
AsmPrinter *AP = const_cast<AsmPrinter*>(this);
if (InlineAsm::isMemKind(OpFlags)) {
Error = AP->PrintAsmMemoryOperand(MI, OpNo, AsmPrinterVariant,
Modifier[0] ? Modifier : 0,
OS);
} else {
Error = AP->PrintAsmOperand(MI, OpNo, AsmPrinterVariant,
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(OS.str(), LocMD);
// 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) {
// Target doesn't support this yet!
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;
}