llvm-6502/lib/Target/X86/X86AsmPrinter.cpp

223 lines
7.8 KiB
C++

//===-- 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 "X86Subtarget.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/Support/CommandLine.h"
using namespace llvm;
Statistic<> llvm::EmittedInsts("asm-printer",
"Number of machine instrs printed");
enum AsmWriterFlavorTy { att, intel };
cl::opt<AsmWriterFlavorTy>
AsmWriterFlavor("x86-asm-syntax",
cl::desc("Choose style of code to emit from X86 backend:"),
cl::values(
clEnumVal(att, " Emit AT&T-style assembly"),
clEnumVal(intel, " Emit Intel-style assembly"),
clEnumValEnd),
cl::init(att));
/// doInitialization
bool X86SharedAsmPrinter::doInitialization(Module &M) {
const X86Subtarget *Subtarget = &TM.getSubtarget<X86Subtarget>();
forDarwin = false;
PrivateGlobalPrefix = ".L";
switch (Subtarget->TargetType) {
case X86Subtarget::isDarwin:
AlignmentIsInBytes = false;
GlobalPrefix = "_";
Data64bitsDirective = 0; // we can't emit a 64-bit unit
ZeroDirective = "\t.space\t"; // ".space N" emits N zeros.
PrivateGlobalPrefix = "L"; // Marker for constant pool idxs
ConstantPoolSection = "\t.const\n";
LCOMMDirective = "\t.lcomm\t";
COMMDirectiveTakesAlignment = false;
HasDotTypeDotSizeDirective = false;
forDarwin = true;
StaticCtorsSection = ".mod_init_func";
StaticDtorsSection = ".mod_term_func";
InlineAsmStart = InlineAsmEnd = ""; // Don't use #APP/#NO_APP
break;
case X86Subtarget::isCygwin:
GlobalPrefix = "_";
COMMDirectiveTakesAlignment = false;
HasDotTypeDotSizeDirective = false;
break;
case X86Subtarget::isWindows:
GlobalPrefix = "_";
HasDotTypeDotSizeDirective = false;
break;
default: break;
}
if (forDarwin) {
// Emit initial debug information.
DW.BeginModule(M);
}
return AsmPrinter::doInitialization(M);
}
bool X86SharedAsmPrinter::doFinalization(Module &M) {
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 = getPreferredAlignmentLog(I);
if (C->isNullValue() && /* FIXME: Verify correct */
(I->hasInternalLinkage() || I->hasWeakLinkage() ||
I->hasLinkOnceLinkage() ||
(forDarwin && 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 {
SwitchSection(".data", I);
if (LCOMMDirective != NULL) {
if (I->hasInternalLinkage()) {
O << LCOMMDirective << name << "," << Size;
if (forDarwin)
O << "," << (AlignmentIsInBytes ? (1 << Align) : Align);
} else
O << COMMDirective << name << "," << Size;
} else {
if (I->hasInternalLinkage())
O << "\t.local\t" << name << "\n";
O << COMMDirective << name << "," << Size;
if (COMMDirectiveTakesAlignment)
O << "," << (AlignmentIsInBytes ? (1 << Align) : Align);
}
}
O << "\t\t" << CommentString << " " << I->getName() << "\n";
} else {
switch (I->getLinkage()) {
case GlobalValue::LinkOnceLinkage:
case GlobalValue::WeakLinkage:
if (forDarwin) {
O << "\t.globl " << name << "\n"
<< "\t.weak_definition " << name << "\n";
SwitchSection(".section __DATA,__datacoal_nt,coalesced", I);
} else {
O << "\t.section\t.llvm.linkonce.d." << name << ",\"aw\",@progbits\n";
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::ExternalLinkage:
// If external or appending, declare as a global symbol
O << "\t.globl " << name << "\n";
// FALL THROUGH
case GlobalValue::InternalLinkage:
SwitchSection(".data", I);
break;
default:
assert(0 && "Unknown linkage type!");
}
EmitAlignment(Align, I);
O << name << ":\t\t\t\t" << CommentString << " " << I->getName()
<< "\n";
if (HasDotTypeDotSizeDirective)
O << "\t.size " << name << ", " << Size << "\n";
EmitGlobalConstant(C);
O << '\n';
}
}
if (forDarwin) {
SwitchSection("", 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) {
SwitchSection(".section __IMPORT,__jump_table,symbol_stubs,"
"self_modifying_code+pure_instructions,5", 0);
O << "L" << *i << "$stub:\n";
O << "\t.indirect_symbol " << *i << "\n";
O << "\thlt ; hlt ; hlt ; hlt ; hlt\n";
}
O << "\n";
// Output stubs for external and common global variables.
if (GVStubs.begin() != GVStubs.end())
SwitchSection(".section __IMPORT,__pointers,non_lazy_symbol_pointers", 0);
for (std::set<std::string>::iterator i = GVStubs.begin(), e = GVStubs.end();
i != e; ++i) {
O << "L" << *i << "$non_lazy_ptr:\n";
O << "\t.indirect_symbol " << *i << "\n";
O << "\t.long\t0\n";
}
// Emit initial debug information.
DW.EndModule(M);
// 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){
switch (AsmWriterFlavor) {
default:
assert(0 && "Unknown asm flavor!");
case intel:
return new X86IntelAsmPrinter(o, tm);
case att:
return new X86ATTAsmPrinter(o, tm);
}
}