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https://github.com/c64scene-ar/llvm-6502.git
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37efe67645
x86 and ppc for 100% dense switch statements when relocations are non-PIC. This support will be extended and enhanced in the coming days to support PIC, and less dense forms of jump tables. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@27947 91177308-0d34-0410-b5e6-96231b3b80d8
232 lines
8.1 KiB
C++
232 lines
8.1 KiB
C++
//===-- X86AsmPrinter.cpp - Convert X86 LLVM IR to X86 assembly -----------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file was developed by the LLVM research group and is distributed under
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// the University of Illinois Open Source License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file the shared super class printer that converts from our internal
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// representation of machine-dependent LLVM code to Intel and AT&T format
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// assembly language.
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// This printer is the output mechanism used by `llc'.
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//
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//===----------------------------------------------------------------------===//
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#include "X86AsmPrinter.h"
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#include "X86ATTAsmPrinter.h"
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#include "X86IntelAsmPrinter.h"
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#include "X86Subtarget.h"
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#include "llvm/Constants.h"
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#include "llvm/Module.h"
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#include "llvm/Type.h"
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#include "llvm/Assembly/Writer.h"
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#include "llvm/Support/Mangler.h"
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#include "llvm/Support/CommandLine.h"
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using namespace llvm;
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Statistic<> llvm::EmittedInsts("asm-printer",
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"Number of machine instrs printed");
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enum AsmWriterFlavorTy { att, intel };
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cl::opt<AsmWriterFlavorTy>
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AsmWriterFlavor("x86-asm-syntax",
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cl::desc("Choose style of code to emit from X86 backend:"),
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cl::values(
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clEnumVal(att, " Emit AT&T-style assembly"),
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clEnumVal(intel, " Emit Intel-style assembly"),
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clEnumValEnd),
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cl::init(att));
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/// doInitialization
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bool X86SharedAsmPrinter::doInitialization(Module &M) {
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const X86Subtarget *Subtarget = &TM.getSubtarget<X86Subtarget>();
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forDarwin = false;
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PrivateGlobalPrefix = ".L";
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switch (Subtarget->TargetType) {
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case X86Subtarget::isDarwin:
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AlignmentIsInBytes = false;
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GlobalPrefix = "_";
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Data64bitsDirective = 0; // we can't emit a 64-bit unit
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ZeroDirective = "\t.space\t"; // ".space N" emits N zeros.
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PrivateGlobalPrefix = "L"; // Marker for constant pool idxs
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ConstantPoolSection = "\t.const\n";
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JumpTableSection = "\t.const\n"; // FIXME: depends on PIC mode
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LCOMMDirective = "\t.lcomm\t";
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COMMDirectiveTakesAlignment = false;
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HasDotTypeDotSizeDirective = false;
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forDarwin = true;
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StaticCtorsSection = ".mod_init_func";
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StaticDtorsSection = ".mod_term_func";
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InlineAsmStart = InlineAsmEnd = ""; // Don't use #APP/#NO_APP
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break;
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case X86Subtarget::isCygwin:
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GlobalPrefix = "_";
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COMMDirectiveTakesAlignment = false;
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HasDotTypeDotSizeDirective = false;
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break;
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case X86Subtarget::isWindows:
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GlobalPrefix = "_";
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HasDotTypeDotSizeDirective = false;
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break;
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default: break;
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}
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if (forDarwin) {
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// Emit initial debug information.
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DW.BeginModule(&M);
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}
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return AsmPrinter::doInitialization(M);
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}
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bool X86SharedAsmPrinter::doFinalization(Module &M) {
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const TargetData &TD = TM.getTargetData();
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// Print out module-level global variables here.
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for (Module::const_global_iterator I = M.global_begin(), E = M.global_end();
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I != E; ++I) {
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if (!I->hasInitializer()) continue; // External global require no code
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// Check to see if this is a special global used by LLVM, if so, emit it.
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if (EmitSpecialLLVMGlobal(I))
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continue;
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std::string name = Mang->getValueName(I);
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Constant *C = I->getInitializer();
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unsigned Size = TD.getTypeSize(C->getType());
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unsigned Align = getPreferredAlignmentLog(I);
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if (C->isNullValue() && /* FIXME: Verify correct */
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(I->hasInternalLinkage() || I->hasWeakLinkage() ||
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I->hasLinkOnceLinkage() ||
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(forDarwin && I->hasExternalLinkage() && !I->hasSection()))) {
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if (Size == 0) Size = 1; // .comm Foo, 0 is undefined, avoid it.
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if (I->hasExternalLinkage()) {
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O << "\t.globl\t" << name << "\n";
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O << "\t.zerofill __DATA__, __common, " << name << ", "
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<< Size << ", " << Align;
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} else {
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SwitchSection(".data", I);
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if (LCOMMDirective != NULL) {
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if (I->hasInternalLinkage()) {
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O << LCOMMDirective << name << "," << Size;
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if (forDarwin)
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O << "," << (AlignmentIsInBytes ? (1 << Align) : Align);
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} else
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O << COMMDirective << name << "," << Size;
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} else {
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if (I->hasInternalLinkage())
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O << "\t.local\t" << name << "\n";
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O << COMMDirective << name << "," << Size;
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if (COMMDirectiveTakesAlignment)
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O << "," << (AlignmentIsInBytes ? (1 << Align) : Align);
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}
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}
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O << "\t\t" << CommentString << " " << I->getName() << "\n";
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} else {
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switch (I->getLinkage()) {
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case GlobalValue::LinkOnceLinkage:
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case GlobalValue::WeakLinkage:
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if (forDarwin) {
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O << "\t.globl " << name << "\n"
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<< "\t.weak_definition " << name << "\n";
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SwitchSection(".section __DATA,__datacoal_nt,coalesced", I);
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} else {
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O << "\t.section\t.llvm.linkonce.d." << name << ",\"aw\",@progbits\n";
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O << "\t.weak " << name << "\n";
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}
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break;
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case GlobalValue::AppendingLinkage:
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// FIXME: appending linkage variables should go into a section of
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// their name or something. For now, just emit them as external.
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case GlobalValue::ExternalLinkage:
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// If external or appending, declare as a global symbol
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O << "\t.globl " << name << "\n";
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// FALL THROUGH
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case GlobalValue::InternalLinkage:
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SwitchSection(".data", I);
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break;
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default:
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assert(0 && "Unknown linkage type!");
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}
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EmitAlignment(Align, I);
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O << name << ":\t\t\t\t" << CommentString << " " << I->getName()
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<< "\n";
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if (HasDotTypeDotSizeDirective)
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O << "\t.size " << name << ", " << Size << "\n";
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EmitGlobalConstant(C);
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O << '\n';
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}
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}
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if (forDarwin) {
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SwitchSection("", 0);
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// Output stubs for dynamically-linked functions
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unsigned j = 1;
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for (std::set<std::string>::iterator i = FnStubs.begin(), e = FnStubs.end();
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i != e; ++i, ++j) {
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SwitchSection(".section __IMPORT,__jump_table,symbol_stubs,"
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"self_modifying_code+pure_instructions,5", 0);
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O << "L" << *i << "$stub:\n";
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O << "\t.indirect_symbol " << *i << "\n";
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O << "\thlt ; hlt ; hlt ; hlt ; hlt\n";
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}
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O << "\n";
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// Output stubs for external and common global variables.
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if (GVStubs.begin() != GVStubs.end())
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SwitchSection(".section __IMPORT,__pointers,non_lazy_symbol_pointers", 0);
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for (std::set<std::string>::iterator i = GVStubs.begin(), e = GVStubs.end();
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i != e; ++i) {
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O << "L" << *i << "$non_lazy_ptr:\n";
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O << "\t.indirect_symbol " << *i << "\n";
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O << "\t.long\t0\n";
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}
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// Emit initial debug information.
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DW.EndModule();
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// Funny Darwin hack: This flag tells the linker that no global symbols
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// contain code that falls through to other global symbols (e.g. the obvious
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// implementation of multiple entry points). If this doesn't occur, the
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// linker can safely perform dead code stripping. Since LLVM never
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// generates code that does this, it is always safe to set.
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O << "\t.subsections_via_symbols\n";
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}
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AsmPrinter::doFinalization(M);
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return false; // success
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}
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void X86SharedAsmPrinter::printBasicBlockLabel(const MachineBasicBlock *MBB)
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const {
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O << PrivateGlobalPrefix << "BB"
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<< Mang->getValueName(MBB->getParent()->getFunction())
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<< "_" << MBB->getNumber() << '\t' << CommentString
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<< MBB->getBasicBlock()->getName();
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}
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/// createX86CodePrinterPass - Returns a pass that prints the X86 assembly code
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/// for a MachineFunction to the given output stream, using the given target
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/// machine description.
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///
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FunctionPass *llvm::createX86CodePrinterPass(std::ostream &o,
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X86TargetMachine &tm){
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switch (AsmWriterFlavor) {
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default:
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assert(0 && "Unknown asm flavor!");
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case intel:
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return new X86IntelAsmPrinter(o, tm);
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case att:
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return new X86ATTAsmPrinter(o, tm);
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}
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}
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