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llvm-project/llvm/lib/Target/X86/X86AsmPrinter.cpp

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//===-- X86AsmPrinter.cpp - Convert X86 LLVM IR to X86 assembly -----------===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by the LLVM research group and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file the shared super class printer that converts from our internal
// representation of machine-dependent LLVM code to Intel and AT&T format
// assembly language.
// This printer is the output mechanism used by `llc'.
//
//===----------------------------------------------------------------------===//
#include "X86AsmPrinter.h"
#include "X86ATTAsmPrinter.h"
#include "X86IntelAsmPrinter.h"
#include "X86MachineFunctionInfo.h"
#include "X86Subtarget.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/CallingConv.h"
#include "llvm/Constants.h"
#include "llvm/Module.h"
#include "llvm/Type.h"
#include "llvm/Assembly/Writer.h"
#include "llvm/Support/Mangler.h"
#include "llvm/Target/TargetAsmInfo.h"
using namespace llvm;
Statistic<> llvm::EmittedInsts("asm-printer",
"Number of machine instrs printed");
static X86FunctionInfo calculateFunctionInfo(const Function *F,
const TargetData *TD) {
X86FunctionInfo Info;
uint64_t Size = 0;
switch (F->getCallingConv()) {
case CallingConv::X86_StdCall:
Info.setDecorationStyle(StdCall);
break;
case CallingConv::X86_FastCall:
Info.setDecorationStyle(FastCall);
break;
default:
return Info;
}
for (Function::const_arg_iterator AI = F->arg_begin(), AE = F->arg_end();
AI != AE; ++AI)
Size += TD->getTypeSize(AI->getType());
// Size should be aligned to DWORD boundary
Size = ((Size + 3)/4)*4;
// We're not supporting tooooo huge arguments :)
Info.setBytesToPopOnReturn((unsigned int)Size);
return Info;
}
/// decorateName - Query FunctionInfoMap and use this information for various
/// name decoration.
void X86SharedAsmPrinter::decorateName(std::string &Name,
const GlobalValue *GV) {
const Function *F = dyn_cast<Function>(GV);
if (!F) return;
// We don't want to decorate non-stdcall or non-fastcall functions right now
unsigned CC = F->getCallingConv();
if (CC != CallingConv::X86_StdCall && CC != CallingConv::X86_FastCall)
return;
FMFInfoMap::const_iterator info_item = FunctionInfoMap.find(F);
const X86FunctionInfo *Info;
if (info_item == FunctionInfoMap.end()) {
// Calculate apropriate function info and populate map
FunctionInfoMap[F] = calculateFunctionInfo(F, TM.getTargetData());
Info = &FunctionInfoMap[F];
} else {
Info = &info_item->second;
}
switch (Info->getDecorationStyle()) {
case None:
break;
case StdCall:
if (!F->isVarArg()) // Variadic functions do not receive @0 suffix.
Name += '@' + utostr_32(Info->getBytesToPopOnReturn());
break;
case FastCall:
if (!F->isVarArg()) // Variadic functions do not receive @0 suffix.
Name += '@' + utostr_32(Info->getBytesToPopOnReturn());
if (Name[0] == '_') {
Name[0] = '@';
} else {
Name = '@' + Name;
}
break;
default:
assert(0 && "Unsupported DecorationStyle");
}
}
/// doInitialization
bool X86SharedAsmPrinter::doInitialization(Module &M) {
if (Subtarget->isTargetDarwin()) {
const X86Subtarget *Subtarget = &TM.getSubtarget<X86Subtarget>();
if (!Subtarget->is64Bit())
X86PICStyle = PICStyle::Stub;
// Emit initial debug information.
DW.BeginModule(&M);
}
return AsmPrinter::doInitialization(M);
}
bool X86SharedAsmPrinter::doFinalization(Module &M) {
// Note: this code is not shared by the Intel printer as it is too different
// from how MASM does things. When making changes here don't forget to look
// at X86IntelAsmPrinter::doFinalization().
const TargetData *TD = TM.getTargetData();
// Print out module-level global variables here.
for (Module::const_global_iterator I = M.global_begin(), E = M.global_end();
I != E; ++I) {
if (!I->hasInitializer()) continue; // External global require no code
// Check to see if this is a special global used by LLVM, if so, emit it.
if (EmitSpecialLLVMGlobal(I))
continue;
std::string name = Mang->getValueName(I);
Constant *C = I->getInitializer();
unsigned Size = TD->getTypeSize(C->getType());
unsigned Align = TD->getPreferredAlignmentLog(I);
if (C->isNullValue() && /* FIXME: Verify correct */
(I->hasInternalLinkage() || I->hasWeakLinkage() ||
I->hasLinkOnceLinkage() ||
(Subtarget->isTargetDarwin() &&
I->hasExternalLinkage() && !I->hasSection()))) {
if (Size == 0) Size = 1; // .comm Foo, 0 is undefined, avoid it.
if (I->hasExternalLinkage()) {
O << "\t.globl\t" << name << "\n";
O << "\t.zerofill __DATA__, __common, " << name << ", "
<< Size << ", " << Align;
} else {
SwitchToDataSection(TAI->getDataSection(), I);
if (TAI->getLCOMMDirective() != NULL) {
if (I->hasInternalLinkage()) {
O << TAI->getLCOMMDirective() << name << "," << Size;
if (Subtarget->isTargetDarwin())
O << "," << (TAI->getAlignmentIsInBytes() ? (1 << Align) : Align);
} else
O << TAI->getCOMMDirective() << name << "," << Size;
} else {
if (!Subtarget->isTargetCygwin()) {
if (I->hasInternalLinkage())
O << "\t.local\t" << name << "\n";
}
O << TAI->getCOMMDirective() << name << "," << Size;
if (TAI->getCOMMDirectiveTakesAlignment())
O << "," << (TAI->getAlignmentIsInBytes() ? (1 << Align) : Align);
}
}
O << "\t\t" << TAI->getCommentString() << " " << I->getName() << "\n";
} else {
switch (I->getLinkage()) {
case GlobalValue::LinkOnceLinkage:
case GlobalValue::WeakLinkage:
if (Subtarget->isTargetDarwin()) {
O << "\t.globl " << name << "\n"
<< "\t.weak_definition " << name << "\n";
SwitchToDataSection(".section __DATA,__const_coal,coalesced", I);
} else if (Subtarget->isTargetCygwin()) {
std::string SectionName(".section\t.data$linkonce." +
name +
",\"aw\"\n");
SwitchToDataSection(SectionName.c_str(), I);
O << "\t.globl " << name << "\n"
<< "\t.linkonce same_size\n";
} else {
std::string SectionName("\t.section\t.llvm.linkonce.d." +
name +
",\"aw\",@progbits\n");
SwitchToDataSection(SectionName.c_str(), I);
O << "\t.weak " << name << "\n";
}
break;
case GlobalValue::AppendingLinkage:
// FIXME: appending linkage variables should go into a section of
// their name or something. For now, just emit them as external.
case GlobalValue::DLLExportLinkage:
DLLExportedGVs.insert(Mang->makeNameProper(I->getName(),""));
// FALL THROUGH
case GlobalValue::ExternalLinkage:
// If external or appending, declare as a global symbol
O << "\t.globl " << name << "\n";
// FALL THROUGH
case GlobalValue::InternalLinkage: {
if (TAI->getCStringSection()) {
const ConstantArray *CVA = dyn_cast<ConstantArray>(C);
if (CVA && CVA->isCString()) {
SwitchToDataSection(TAI->getCStringSection(), I);
break;
}
}
SwitchToDataSection(TAI->getDataSection(), I);
break;
}
default:
assert(0 && "Unknown linkage type!");
}
EmitAlignment(Align, I);
O << name << ":\t\t\t\t" << TAI->getCommentString() << " " << I->getName()
<< "\n";
if (TAI->hasDotTypeDotSizeDirective())
O << "\t.size " << name << ", " << Size << "\n";
EmitGlobalConstant(C);
O << '\n';
}
}
// Output linker support code for dllexported globals
if (DLLExportedGVs.begin() != DLLExportedGVs.end()) {
SwitchToDataSection(".section .drectve", 0);
}
for (std::set<std::string>::iterator i = DLLExportedGVs.begin(),
e = DLLExportedGVs.end();
i != e; ++i) {
O << "\t.ascii \" -export:" << *i << ",data\"\n";
}
if (DLLExportedFns.begin() != DLLExportedFns.end()) {
SwitchToDataSection(".section .drectve", 0);
}
for (std::set<std::string>::iterator i = DLLExportedFns.begin(),
e = DLLExportedFns.end();
i != e; ++i) {
O << "\t.ascii \" -export:" << *i << "\"\n";
}
if (Subtarget->isTargetDarwin()) {
SwitchToDataSection("", 0);
// Output stubs for dynamically-linked functions
unsigned j = 1;
for (std::set<std::string>::iterator i = FnStubs.begin(), e = FnStubs.end();
i != e; ++i, ++j) {
SwitchToDataSection(".section __IMPORT,__jump_table,symbol_stubs,"
"self_modifying_code+pure_instructions,5", 0);
O << "L" << *i << "$stub:\n";
O << "\t.indirect_symbol " << *i << "\n";
O << "\thlt ; hlt ; hlt ; hlt ; hlt\n";
}
O << "\n";
// Output stubs for external and common global variables.
if (GVStubs.begin() != GVStubs.end())
SwitchToDataSection(
".section __IMPORT,__pointers,non_lazy_symbol_pointers", 0);
for (std::set<std::string>::iterator i = GVStubs.begin(), e = GVStubs.end();
i != e; ++i) {
O << "L" << *i << "$non_lazy_ptr:\n";
O << "\t.indirect_symbol " << *i << "\n";
O << "\t.long\t0\n";
}
// Emit initial debug information.
DW.EndModule();
// Funny Darwin hack: This flag tells the linker that no global symbols
// contain code that falls through to other global symbols (e.g. the obvious
// implementation of multiple entry points). If this doesn't occur, the
// linker can safely perform dead code stripping. Since LLVM never
// generates code that does this, it is always safe to set.
O << "\t.subsections_via_symbols\n";
}
AsmPrinter::doFinalization(M);
return false; // success
}
/// createX86CodePrinterPass - Returns a pass that prints the X86 assembly code
/// for a MachineFunction to the given output stream, using the given target
/// machine description.
///
FunctionPass *llvm::createX86CodePrinterPass(std::ostream &o,
X86TargetMachine &tm) {
const X86Subtarget *Subtarget = &tm.getSubtarget<X86Subtarget>();
if (Subtarget->isFlavorIntel()) {
return new X86IntelAsmPrinter(o, tm, tm.getTargetAsmInfo());
} else {
return new X86ATTAsmPrinter(o, tm, tm.getTargetAsmInfo());
}
}
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