llvm/lib/Target/X86/X86TargetAsmInfo.cpp
Chris Lattner b266ccd0f4 Modify emission of jump tables on darwin to emit an extra "l" label that
delimits the boundaries of jump tables.  This lets the linker's dead code
stripping optimization do a better job.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@33315 91177308-0d34-0410-b5e6-96231b3b80d8
2007-01-18 01:15:58 +00:00

268 lines
10 KiB
C++

//===-- X86TargetAsmInfo.cpp - X86 asm properties ---------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by James M. Laskey and is distributed under the
// University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file contains the declarations of the X86TargetAsmInfo properties.
//
//===----------------------------------------------------------------------===//
#include "X86TargetAsmInfo.h"
#include "X86TargetMachine.h"
#include "X86Subtarget.h"
#include "llvm/DerivedTypes.h"
#include "llvm/InlineAsm.h"
#include "llvm/Instructions.h"
#include "llvm/Module.h"
#include "llvm/ADT/StringExtras.h"
using namespace llvm;
static const char* x86_asm_table[] = {"{si}", "S",
"{di}", "D",
"{ax}", "a",
"{cx}", "c",
"{memory}", "memory",
"{flags}", "",
"{dirflag}", "",
"{fpsr}", "",
"{cc}", "cc",
0,0};
X86TargetAsmInfo::X86TargetAsmInfo(const X86TargetMachine &TM) {
const X86Subtarget *Subtarget = &TM.getSubtarget<X86Subtarget>();
// FIXME - Should be simplified.
AsmTransCBE = x86_asm_table;
switch (Subtarget->TargetType) {
case X86Subtarget::isDarwin:
AlignmentIsInBytes = false;
GlobalPrefix = "_";
if (!Subtarget->is64Bit())
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
BSSSection = 0; // no BSS section.
ZeroFillDirective = "\t.zerofill\t"; // Uses .zerofill
ConstantPoolSection = "\t.const\n";
JumpTableDataSection = "\t.const\n";
CStringSection = "\t.cstring";
FourByteConstantSection = "\t.literal4\n";
EightByteConstantSection = "\t.literal8\n";
if (Subtarget->is64Bit())
SixteenByteConstantSection = "\t.literal16\n";
LCOMMDirective = "\t.lcomm\t";
COMMDirectiveTakesAlignment = false;
HasDotTypeDotSizeDirective = false;
StaticCtorsSection = ".mod_init_func";
StaticDtorsSection = ".mod_term_func";
InlineAsmStart = "# InlineAsm Start";
InlineAsmEnd = "# InlineAsm End";
SetDirective = "\t.set";
UsedDirective = "\t.no_dead_strip\t";
WeakRefDirective = "\t.weak_reference\t";
HiddenDirective = "\t.private_extern\t";
// In non-PIC modes, emit a special label before jump tables so that the
// linker can perform more accurate dead code stripping.
if (TM.getRelocationModel() != Reloc::PIC_) {
// Emit a local label that is preserved until the linker runs.
JumpTableSpecialLabelPrefix = "l";
}
NeedsSet = true;
DwarfAbbrevSection = ".section __DWARF,__debug_abbrev,regular,debug";
DwarfInfoSection = ".section __DWARF,__debug_info,regular,debug";
DwarfLineSection = ".section __DWARF,__debug_line,regular,debug";
DwarfFrameSection = ".section __DWARF,__debug_frame,regular,debug";
DwarfPubNamesSection = ".section __DWARF,__debug_pubnames,regular,debug";
DwarfPubTypesSection = ".section __DWARF,__debug_pubtypes,regular,debug";
DwarfStrSection = ".section __DWARF,__debug_str,regular,debug";
DwarfLocSection = ".section __DWARF,__debug_loc,regular,debug";
DwarfARangesSection = ".section __DWARF,__debug_aranges,regular,debug";
DwarfRangesSection = ".section __DWARF,__debug_ranges,regular,debug";
DwarfMacInfoSection = ".section __DWARF,__debug_macinfo,regular,debug";
break;
case X86Subtarget::isELF:
// Set up DWARF directives
HasLEB128 = true; // Target asm supports leb128 directives (little-endian)
// bool HasLEB128; // Defaults to false.
// hasDotLoc - True if target asm supports .loc directives.
// bool HasDotLoc; // Defaults to false.
// HasDotFile - True if target asm supports .file directives.
// bool HasDotFile; // Defaults to false.
PrivateGlobalPrefix = ".L";
WeakRefDirective = "\t.weak\t";
DwarfRequiresFrameSection = false;
DwarfAbbrevSection = "\t.section\t.debug_abbrev,\"\",@progbits";
DwarfInfoSection = "\t.section\t.debug_info,\"\",@progbits";
DwarfLineSection = "\t.section\t.debug_line,\"\",@progbits";
DwarfFrameSection = "\t.section\t.debug_frame,\"\",@progbits";
DwarfPubNamesSection ="\t.section\t.debug_pubnames,\"\",@progbits";
DwarfPubTypesSection ="\t.section\t.debug_pubtypes,\"\",@progbits";
DwarfStrSection = "\t.section\t.debug_str,\"\",@progbits";
DwarfLocSection = "\t.section\t.debug_loc,\"\",@progbits";
DwarfARangesSection = "\t.section\t.debug_aranges,\"\",@progbits";
DwarfRangesSection = "\t.section\t.debug_ranges,\"\",@progbits";
DwarfMacInfoSection = "\t.section\t.debug_macinfo,\"\",@progbits";
break;
case X86Subtarget::isCygwin:
case X86Subtarget::isMingw:
GlobalPrefix = "_";
LCOMMDirective = "\t.lcomm\t";
COMMDirectiveTakesAlignment = false;
HasDotTypeDotSizeDirective = false;
StaticCtorsSection = "\t.section .ctors,\"aw\"";
StaticDtorsSection = "\t.section .dtors,\"aw\"";
HiddenDirective = NULL;
// Set up DWARF directives
HasLEB128 = true; // Target asm supports leb128 directives (little-endian)
PrivateGlobalPrefix = "L"; // Prefix for private global symbols
DwarfRequiresFrameSection = false;
DwarfAbbrevSection = "\t.section\t.debug_abbrev,\"dr\"";
DwarfInfoSection = "\t.section\t.debug_info,\"dr\"";
DwarfLineSection = "\t.section\t.debug_line,\"dr\"";
DwarfFrameSection = "\t.section\t.debug_frame,\"dr\"";
DwarfPubNamesSection ="\t.section\t.debug_pubnames,\"dr\"";
DwarfPubTypesSection ="\t.section\t.debug_pubtypes,\"dr\"";
DwarfStrSection = "\t.section\t.debug_str,\"dr\"";
DwarfLocSection = "\t.section\t.debug_loc,\"dr\"";
DwarfARangesSection = "\t.section\t.debug_aranges,\"dr\"";
DwarfRangesSection = "\t.section\t.debug_ranges,\"dr\"";
DwarfMacInfoSection = "\t.section\t.debug_macinfo,\"dr\"";
break;
case X86Subtarget::isWindows:
GlobalPrefix = "_";
HasDotTypeDotSizeDirective = false;
break;
default: break;
}
if (Subtarget->isFlavorIntel()) {
GlobalPrefix = "_";
CommentString = ";";
PrivateGlobalPrefix = "$";
AlignDirective = "\talign\t";
ZeroDirective = "\tdb\t";
ZeroDirectiveSuffix = " dup(0)";
AsciiDirective = "\tdb\t";
AscizDirective = 0;
Data8bitsDirective = "\tdb\t";
Data16bitsDirective = "\tdw\t";
Data32bitsDirective = "\tdd\t";
Data64bitsDirective = "\tdq\t";
HasDotTypeDotSizeDirective = false;
TextSection = "_text";
DataSection = "_data";
JumpTableDataSection = NULL;
SwitchToSectionDirective = "";
TextSectionStartSuffix = "\tsegment 'CODE'";
DataSectionStartSuffix = "\tsegment 'DATA'";
SectionEndDirectiveSuffix = "\tends\n";
}
AssemblerDialect = Subtarget->getAsmFlavor();
}
bool X86TargetAsmInfo::LowerToBSwap(CallInst *CI) const {
// FIXME: this should verify that we are targetting a 486 or better. If not,
// we will turn this bswap into something that will be lowered to logical ops
// instead of emitting the bswap asm. For now, we don't support 486 or lower
// so don't worry about this.
// Verify this is a simple bswap.
if (CI->getNumOperands() != 2 ||
CI->getType() != CI->getOperand(1)->getType() ||
!CI->getType()->isInteger())
return false;
const Type *Ty = CI->getType();
const char *IntName;
if (const IntegerType *ITy = dyn_cast<IntegerType>(Ty)) {
unsigned BitWidth = ITy->getBitWidth();
if (BitWidth == 16)
IntName = "llvm.bswap.i16";
else if (BitWidth == 32)
IntName = "llvm.bswap.i32";
else if (BitWidth == 64)
IntName = "llvm.bswap.i64";
else
return false;
} else
return false;
// Okay, we can do this xform, do so now.
Module *M = CI->getParent()->getParent()->getParent();
Constant *Int = M->getOrInsertFunction(IntName, Ty, Ty, (Type*)0);
Value *Op = CI->getOperand(1);
Op = new CallInst(Int, Op, CI->getName(), CI);
CI->replaceAllUsesWith(Op);
CI->eraseFromParent();
return true;
}
bool X86TargetAsmInfo::ExpandInlineAsm(CallInst *CI) const {
InlineAsm *IA = cast<InlineAsm>(CI->getCalledValue());
std::vector<InlineAsm::ConstraintInfo> Constraints = IA->ParseConstraints();
std::string AsmStr = IA->getAsmString();
// TODO: should remove alternatives from the asmstring: "foo {a|b}" -> "foo a"
std::vector<std::string> AsmPieces;
SplitString(AsmStr, AsmPieces, "\n"); // ; as separator?
switch (AsmPieces.size()) {
default: return false;
case 1:
AsmStr = AsmPieces[0];
AsmPieces.clear();
SplitString(AsmStr, AsmPieces, " \t"); // Split with whitespace.
// bswap $0
if (AsmPieces.size() == 2 &&
AsmPieces[0] == "bswap" && AsmPieces[1] == "$0") {
// No need to check constraints, nothing other than the equivalent of
// "=r,0" would be valid here.
return LowerToBSwap(CI);
}
break;
case 3:
if (CI->getType() == Type::Int64Ty && Constraints.size() >= 2 &&
Constraints[0].Codes.size() == 1 && Constraints[0].Codes[0] == "A" &&
Constraints[1].Codes.size() == 1 && Constraints[1].Codes[0] == "0") {
// bswap %eax / bswap %edx / xchgl %eax, %edx -> llvm.bswap.i64
std::vector<std::string> Words;
SplitString(AsmPieces[0], Words, " \t");
if (Words.size() == 2 && Words[0] == "bswap" && Words[1] == "%eax") {
Words.clear();
SplitString(AsmPieces[1], Words, " \t");
if (Words.size() == 2 && Words[0] == "bswap" && Words[1] == "%edx") {
Words.clear();
SplitString(AsmPieces[2], Words, " \t,");
if (Words.size() == 3 && Words[0] == "xchgl" && Words[1] == "%eax" &&
Words[2] == "%edx") {
return LowerToBSwap(CI);
}
}
}
}
break;
}
return false;
}