mirror of
https://github.com/c64scene-ar/llvm-6502.git
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afcb70bc73
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@77203 91177308-0d34-0410-b5e6-96231b3b80d8
401 lines
13 KiB
C++
401 lines
13 KiB
C++
//===-- TargetAsmInfo.cpp - Asm Info ---------------------------------------==//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file defines target asm properties related what form asm statements
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// should take.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Constants.h"
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#include "llvm/DerivedTypes.h"
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#include "llvm/GlobalVariable.h"
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#include "llvm/Function.h"
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#include "llvm/Module.h"
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#include "llvm/Type.h"
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#include "llvm/Target/TargetAsmInfo.h"
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#include "llvm/Target/TargetData.h"
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#include "llvm/Target/TargetMachine.h"
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#include "llvm/Target/TargetOptions.h"
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#include "llvm/Support/Dwarf.h"
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#include "llvm/Support/ErrorHandling.h"
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#include <cctype>
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#include <cstring>
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using namespace llvm;
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TargetAsmInfo::TargetAsmInfo(const TargetMachine &tm) : TM(tm) {
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BSSSection = "\t.bss";
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BSSSection_ = 0;
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ReadOnlySection = 0;
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TLSDataSection = 0;
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TLSBSSSection = 0;
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ZeroFillDirective = 0;
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NonexecutableStackDirective = 0;
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NeedsSet = false;
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MaxInstLength = 4;
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PCSymbol = "$";
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SeparatorChar = ';';
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CommentColumn = 60;
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CommentString = "#";
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FirstOperandColumn = 0;
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MaxOperandLength = 0;
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GlobalPrefix = "";
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PrivateGlobalPrefix = ".";
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LinkerPrivateGlobalPrefix = "";
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JumpTableSpecialLabelPrefix = 0;
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GlobalVarAddrPrefix = "";
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GlobalVarAddrSuffix = "";
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FunctionAddrPrefix = "";
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FunctionAddrSuffix = "";
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PersonalityPrefix = "";
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PersonalitySuffix = "";
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NeedsIndirectEncoding = false;
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InlineAsmStart = "#APP";
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InlineAsmEnd = "#NO_APP";
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AssemblerDialect = 0;
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AllowQuotesInName = false;
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ZeroDirective = "\t.zero\t";
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ZeroDirectiveSuffix = 0;
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AsciiDirective = "\t.ascii\t";
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AscizDirective = "\t.asciz\t";
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Data8bitsDirective = "\t.byte\t";
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Data16bitsDirective = "\t.short\t";
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Data32bitsDirective = "\t.long\t";
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Data64bitsDirective = "\t.quad\t";
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AlignDirective = "\t.align\t";
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AlignmentIsInBytes = true;
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TextAlignFillValue = 0;
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SwitchToSectionDirective = "\t.section\t";
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TextSectionStartSuffix = "";
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DataSectionStartSuffix = "";
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SectionEndDirectiveSuffix = 0;
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ConstantPoolSection = "\t.section .rodata";
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JumpTableDataSection = "\t.section .rodata";
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JumpTableDirective = 0;
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CStringSection = 0;
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CStringSection_ = 0;
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// FIXME: Flags are ELFish - replace with normal section stuff.
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StaticCtorsSection = "\t.section .ctors,\"aw\",@progbits";
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StaticDtorsSection = "\t.section .dtors,\"aw\",@progbits";
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GlobalDirective = "\t.globl\t";
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SetDirective = 0;
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LCOMMDirective = 0;
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COMMDirective = "\t.comm\t";
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COMMDirectiveTakesAlignment = true;
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HasDotTypeDotSizeDirective = true;
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HasSingleParameterDotFile = true;
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UsedDirective = 0;
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WeakRefDirective = 0;
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WeakDefDirective = 0;
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// FIXME: These are ELFish - move to ELFTAI.
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HiddenDirective = "\t.hidden\t";
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ProtectedDirective = "\t.protected\t";
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AbsoluteDebugSectionOffsets = false;
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AbsoluteEHSectionOffsets = false;
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HasLEB128 = false;
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HasDotLocAndDotFile = false;
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SupportsDebugInformation = false;
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SupportsExceptionHandling = false;
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DwarfRequiresFrameSection = true;
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DwarfUsesInlineInfoSection = false;
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Is_EHSymbolPrivate = true;
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GlobalEHDirective = 0;
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SupportsWeakOmittedEHFrame = true;
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DwarfSectionOffsetDirective = 0;
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DwarfAbbrevSection = ".debug_abbrev";
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DwarfInfoSection = ".debug_info";
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DwarfLineSection = ".debug_line";
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DwarfFrameSection = ".debug_frame";
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DwarfPubNamesSection = ".debug_pubnames";
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DwarfPubTypesSection = ".debug_pubtypes";
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DwarfDebugInlineSection = ".debug_inlined";
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DwarfStrSection = ".debug_str";
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DwarfLocSection = ".debug_loc";
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DwarfARangesSection = ".debug_aranges";
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DwarfRangesSection = ".debug_ranges";
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DwarfMacroInfoSection = ".debug_macinfo";
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DwarfEHFrameSection = ".eh_frame";
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DwarfExceptionSection = ".gcc_except_table";
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AsmTransCBE = 0;
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}
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TargetAsmInfo::~TargetAsmInfo() {
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}
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/// Measure the specified inline asm to determine an approximation of its
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/// length.
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/// Comments (which run till the next SeparatorChar or newline) do not
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/// count as an instruction.
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/// Any other non-whitespace text is considered an instruction, with
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/// multiple instructions separated by SeparatorChar or newlines.
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/// Variable-length instructions are not handled here; this function
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/// may be overloaded in the target code to do that.
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unsigned TargetAsmInfo::getInlineAsmLength(const char *Str) const {
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// Count the number of instructions in the asm.
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bool atInsnStart = true;
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unsigned Length = 0;
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for (; *Str; ++Str) {
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if (*Str == '\n' || *Str == SeparatorChar)
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atInsnStart = true;
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if (atInsnStart && !isspace(*Str)) {
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Length += MaxInstLength;
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atInsnStart = false;
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}
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if (atInsnStart && strncmp(Str, CommentString, strlen(CommentString))==0)
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atInsnStart = false;
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}
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return Length;
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}
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unsigned TargetAsmInfo::PreferredEHDataFormat(DwarfEncoding::Target Reason,
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bool Global) const {
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return dwarf::DW_EH_PE_absptr;
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}
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static bool isSuitableForBSS(const GlobalVariable *GV) {
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Constant *C = GV->getInitializer();
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// Must have zero initializer.
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if (!C->isNullValue())
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return false;
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// Leave constant zeros in readonly constant sections, so they can be shared.
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if (GV->isConstant())
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return false;
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// If the global has an explicit section specified, don't put it in BSS.
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if (!GV->getSection().empty())
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return false;
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// If -nozero-initialized-in-bss is specified, don't ever use BSS.
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if (NoZerosInBSS)
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return false;
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// Otherwise, put it in BSS!
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return true;
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}
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static bool isConstantString(const Constant *C) {
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// First check: is we have constant array of i8 terminated with zero
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const ConstantArray *CVA = dyn_cast<ConstantArray>(C);
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// Check, if initializer is a null-terminated string
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if (CVA && CVA->isCString())
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return true;
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// Another possibility: [1 x i8] zeroinitializer
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if (isa<ConstantAggregateZero>(C))
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if (const ArrayType *Ty = dyn_cast<ArrayType>(C->getType()))
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return (Ty->getElementType() == Type::Int8Ty &&
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Ty->getNumElements() == 1);
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return false;
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}
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static SectionKind::Kind SectionKindForGlobal(const GlobalValue *GV,
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const TargetMachine &TM) {
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Reloc::Model ReloModel = TM.getRelocationModel();
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// Early exit - functions should be always in text sections.
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const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GV);
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if (GVar == 0)
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return SectionKind::Text;
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// Handle thread-local data first.
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if (GVar->isThreadLocal()) {
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if (isSuitableForBSS(GVar))
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return SectionKind::ThreadBSS;
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return SectionKind::ThreadData;
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}
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// Variable can be easily put to BSS section.
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if (isSuitableForBSS(GVar))
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return SectionKind::BSS;
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Constant *C = GVar->getInitializer();
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// If the global is marked constant, we can put it into a mergable section,
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// a mergable string section, or general .data if it contains relocations.
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if (GVar->isConstant()) {
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// If the initializer for the global contains something that requires a
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// relocation, then we may have to drop this into a wriable data section
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// even though it is marked const.
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switch (C->getRelocationInfo()) {
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default: llvm_unreachable("unknown relocation info kind");
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case Constant::NoRelocation:
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// If initializer is a null-terminated string, put it in a "cstring"
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// section if the target has it.
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if (isConstantString(C))
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return SectionKind::MergeableCString;
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// Otherwise, just drop it into a mergable constant section. If we have
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// a section for this size, use it, otherwise use the arbitrary sized
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// mergable section.
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switch (TM.getTargetData()->getTypeAllocSize(C->getType())) {
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case 4: return SectionKind::MergeableConst4;
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case 8: return SectionKind::MergeableConst8;
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case 16: return SectionKind::MergeableConst16;
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default: return SectionKind::MergeableConst;
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}
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case Constant::LocalRelocation:
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// In static relocation model, the linker will resolve all addresses, so
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// the relocation entries will actually be constants by the time the app
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// starts up.
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if (ReloModel == Reloc::Static)
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return SectionKind::ReadOnly;
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// Otherwise, the dynamic linker needs to fix it up, put it in the
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// writable data.rel.local section.
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return SectionKind::ReadOnlyWithRelLocal;
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case Constant::GlobalRelocations:
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// In static relocation model, the linker will resolve all addresses, so
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// the relocation entries will actually be constants by the time the app
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// starts up.
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if (ReloModel == Reloc::Static)
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return SectionKind::ReadOnly;
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// Otherwise, the dynamic linker needs to fix it up, put it in the
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// writable data.rel section.
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return SectionKind::ReadOnlyWithRel;
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}
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}
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// Okay, this isn't a constant. If the initializer for the global is going
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// to require a runtime relocation by the dynamic linker, put it into a more
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// specific section to improve startup time of the app. This coalesces these
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// globals together onto fewer pages, improving the locality of the dynamic
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// linker.
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if (ReloModel == Reloc::Static)
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return SectionKind::DataNoRel;
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switch (C->getRelocationInfo()) {
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default: llvm_unreachable("unknown relocation info kind");
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case Constant::NoRelocation:
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return SectionKind::DataNoRel;
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case Constant::LocalRelocation:
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return SectionKind::DataRelLocal;
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case Constant::GlobalRelocations:
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return SectionKind::DataRel;
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}
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}
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/// SectionForGlobal - This method computes the appropriate section to emit
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/// the specified global variable or function definition. This should not
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/// be passed external (or available externally) globals.
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const Section *TargetAsmInfo::SectionForGlobal(const GlobalValue *GV) const {
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assert(!GV->isDeclaration() && !GV->hasAvailableExternallyLinkage() &&
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"Can only be used for global definitions");
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SectionKind::Kind GVKind = SectionKindForGlobal(GV, TM);
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SectionKind Kind = SectionKind::get(GVKind, GV->isWeakForLinker(),
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GV->hasSection());
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// Select section name.
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if (GV->hasSection()) {
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// If the target has special section hacks for specifically named globals,
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// return them now.
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if (const Section *TS = getSpecialCasedSectionGlobals(GV, Kind))
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return TS;
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// If the target has magic semantics for certain section names, make sure to
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// pick up the flags. This allows the user to write things with attribute
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// section and still get the appropriate section flags printed.
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GVKind = getKindForNamedSection(GV->getSection().c_str(), GVKind);
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return getOrCreateSection(GV->getSection().c_str(), false, GVKind);
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}
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// If this global is linkonce/weak and the target handles this by emitting it
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// into a 'uniqued' section name, create and return the section now.
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if (Kind.isWeak()) {
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if (const char *Prefix = getSectionPrefixForUniqueGlobal(Kind)) {
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// FIXME: Use mangler interface (PR4584).
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std::string Name = Prefix+GV->getNameStr();
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return getOrCreateSection(Name.c_str(), false, GVKind);
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}
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}
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// Use default section depending on the 'type' of global
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return SelectSectionForGlobal(GV, Kind);
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}
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// Lame default implementation. Calculate the section name for global.
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const Section*
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TargetAsmInfo::SelectSectionForGlobal(const GlobalValue *GV,
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SectionKind Kind) const {
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assert(!Kind.isThreadLocal() && "Doesn't support TLS");
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if (Kind.isText())
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return getTextSection();
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if (Kind.isBSS())
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if (const Section *S = getBSSSection_())
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return S;
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if (Kind.isReadOnly())
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if (const Section *S = getReadOnlySection())
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return S;
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return getDataSection();
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}
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/// getSectionForMergableConstant - Given a mergable constant with the
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/// specified size and relocation information, return a section that it
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/// should be placed in.
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const Section *
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TargetAsmInfo::getSectionForMergeableConstant(SectionKind Kind) const {
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if (Kind.isReadOnly())
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if (const Section *S = getReadOnlySection())
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return S;
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return getDataSection();
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}
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const Section *TargetAsmInfo::getOrCreateSection(const char *Name,
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bool isDirective,
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SectionKind::Kind Kind) const {
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Section &S = Sections[Name];
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// This is newly-created section, set it up properly.
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if (S.Name.empty()) {
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S.Kind = SectionKind::get(Kind, false /*weak*/, !isDirective);
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S.Name = Name;
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}
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return &S;
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}
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unsigned TargetAsmInfo::getULEB128Size(unsigned Value) {
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unsigned Size = 0;
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do {
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Value >>= 7;
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Size += sizeof(int8_t);
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} while (Value);
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return Size;
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}
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unsigned TargetAsmInfo::getSLEB128Size(int Value) {
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unsigned Size = 0;
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int Sign = Value >> (8 * sizeof(Value) - 1);
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bool IsMore;
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do {
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unsigned Byte = Value & 0x7f;
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Value >>= 7;
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IsMore = Value != Sign || ((Byte ^ Sign) & 0x40) != 0;
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Size += sizeof(int8_t);
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} while (IsMore);
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return Size;
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}
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