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Implement .reloc (constant offset only) with support for R_MIPS_NONE and R_MIPS_32. 

Summary:
Support for R_MIPS_NONE allows us to parse MIPS16's usage of .reloc.
R_MIPS_32 was included to be able to better test the directive.

Targets can add their relocations by overriding MCAsmBackend::getFixupKind().

Subscribers: grosbach, rafael, majnemer, dsanders, llvm-commits

Differential Revision: http://reviews.llvm.org/D13659

llvm-svn: 252888
This commit is contained in:
Daniel Sanders 2015-11-12 13:33:00 +00:00
parent e342469c0a
commit 9f6ad49740
13 changed files with 191 additions and 1 deletions
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5
llvm/include/llvm/MC/MCAsmBackend.h
View File

@ -67,6 +67,11 @@ public:
/// Get the number of target specific fixup kinds.
virtual unsigned getNumFixupKinds() const = 0;
/// Map a relocation name used in .reloc to a fixup kind.
/// Returns true and sets MappedKind if Name is successfully mapped.
/// Otherwise returns false and leaves MappedKind unchanged.
virtual bool getFixupKind(StringRef Name, MCFixupKind &MappedKind) const;
/// Get information on a fixup kind.
virtual const MCFixupKindInfo &getFixupKindInfo(MCFixupKind Kind) const;

2
llvm/include/llvm/MC/MCObjectStreamer.h
View File

@ -124,6 +124,8 @@ public:
const MCSymbol *Label);
void EmitGPRel32Value(const MCExpr *Value) override;
void EmitGPRel64Value(const MCExpr *Value) override;
bool EmitRelocDirective(const MCExpr &Offset, StringRef Name,
const MCExpr *Expr, SMLoc Loc) override;
void EmitFill(uint64_t NumBytes, uint8_t FillValue) override;
void FinishImpl() override;

8
llvm/include/llvm/MC/MCStreamer.h
View File

@ -682,6 +682,14 @@ public:
virtual void EmitSyntaxDirective();
/// \brief Emit a .reloc directive.
/// Returns true if the relocation could not be emitted because Name is not
/// known.
virtual bool EmitRelocDirective(const MCExpr &Offset, StringRef Name,
const MCExpr *Expr, SMLoc Loc) {
return true;
}
/// \brief Emit the given \p Instruction into the current section.
virtual void EmitInstruction(const MCInst &Inst, const MCSubtargetInfo &STI);

4
llvm/lib/MC/MCAsmBackend.cpp
View File

@ -16,6 +16,10 @@ MCAsmBackend::MCAsmBackend() : HasDataInCodeSupport(false) {}
MCAsmBackend::~MCAsmBackend() {}
bool MCAsmBackend::getFixupKind(StringRef Name, MCFixupKind &MappedKind) const {
return false;
}
const MCFixupKindInfo &MCAsmBackend::getFixupKindInfo(MCFixupKind Kind) const {
static const MCFixupKindInfo Builtins[] = {
{"FK_Data_1", 0, 8, 0},

16
llvm/lib/MC/MCAsmStreamer.cpp
View File

@ -240,6 +240,9 @@ public:
void EmitBundleLock(bool AlignToEnd) override;
void EmitBundleUnlock() override;
bool EmitRelocDirective(const MCExpr &Offset, StringRef Name,
const MCExpr *Expr, SMLoc Loc) override;
/// EmitRawText - If this file is backed by an assembly streamer, this dumps
/// the specified string in the output .s file. This capability is
/// indicated by the hasRawTextSupport() predicate.
@ -1357,6 +1360,19 @@ void MCAsmStreamer::EmitBundleUnlock() {
EmitEOL();
}
bool MCAsmStreamer::EmitRelocDirective(const MCExpr &Offset, StringRef Name,
const MCExpr *Expr, SMLoc) {
OS << "\t.reloc ";
Offset.print(OS, MAI);
OS << ", " << Name;
if (Expr) {
OS << ", ";
Expr->print(OS, MAI);
}
EmitEOL();
return false;
}
/// EmitRawText - If this file is backed by an assembly streamer, this dumps
/// the specified string in the output .s file. This capability is
/// indicated by the hasRawTextSupport() predicate.

20
llvm/lib/MC/MCObjectStreamer.cpp
View File

@ -416,6 +416,26 @@ void MCObjectStreamer::EmitGPRel64Value(const MCExpr *Value) {
DF->getContents().resize(DF->getContents().size() + 8, 0);
}
bool MCObjectStreamer::EmitRelocDirective(const MCExpr &Offset, StringRef Name,
const MCExpr *Expr, SMLoc Loc) {
int64_t OffsetValue;
if (!Offset.evaluateAsAbsolute(OffsetValue))
llvm_unreachable("Offset is not absolute");
MCDataFragment *DF = getOrCreateDataFragment();
flushPendingLabels(DF, DF->getContents().size());
MCFixupKind Kind;
if (!Assembler->getBackend().getFixupKind(Name, Kind))
return true;
if (Expr == nullptr)
Expr =
MCSymbolRefExpr::create(getContext().createTempSymbol(), getContext());
DF->getFixups().push_back(MCFixup::create(OffsetValue, Expr, Kind, Loc));
return false;
}
void MCObjectStreamer::EmitFill(uint64_t NumBytes, uint8_t FillValue) {
const MCSection *Sec = getCurrentSection().first;
assert(Sec && "need a section");

51
llvm/lib/MC/MCParser/AsmParser.cpp
View File

@ -33,6 +33,7 @@
#include "llvm/MC/MCStreamer.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/MC/MCTargetAsmParser.h"
#include "llvm/MC/MCValue.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/MathExtras.h"
@ -342,6 +343,7 @@ private:
enum DirectiveKind {
DK_NO_DIRECTIVE, // Placeholder
DK_SET, DK_EQU, DK_EQUIV, DK_ASCII, DK_ASCIZ, DK_STRING, DK_BYTE, DK_SHORT,
DK_RELOC,
DK_VALUE, DK_2BYTE, DK_LONG, DK_INT, DK_4BYTE, DK_QUAD, DK_8BYTE, DK_OCTA,
DK_SINGLE, DK_FLOAT, DK_DOUBLE, DK_ALIGN, DK_ALIGN32, DK_BALIGN, DK_BALIGNW,
DK_BALIGNL, DK_P2ALIGN, DK_P2ALIGNW, DK_P2ALIGNL, DK_ORG, DK_FILL, DK_ENDR,
@ -374,6 +376,7 @@ private:
// ".ascii", ".asciz", ".string"
bool parseDirectiveAscii(StringRef IDVal, bool ZeroTerminated);
bool parseDirectiveReloc(SMLoc DirectiveLoc); // ".reloc"
bool parseDirectiveValue(unsigned Size); // ".byte", ".long", ...
bool parseDirectiveOctaValue(); // ".octa"
bool parseDirectiveRealValue(const fltSemantics &); // ".single", ...
@ -1695,6 +1698,8 @@ bool AsmParser::parseStatement(ParseStatementInfo &Info,
return parseDirectiveError(IDLoc, true);
case DK_WARNING:
return parseDirectiveWarning(IDLoc);
case DK_RELOC:
return parseDirectiveReloc(IDLoc);
}
return Error(IDLoc, "unknown directive");
@ -2463,6 +2468,51 @@ bool AsmParser::parseDirectiveAscii(StringRef IDVal, bool ZeroTerminated) {
return false;
}
/// parseDirectiveReloc
/// ::= .reloc expression , identifier [ , expression ]
bool AsmParser::parseDirectiveReloc(SMLoc DirectiveLoc) {
const MCExpr *Offset;
const MCExpr *Expr = nullptr;
SMLoc OffsetLoc = Lexer.getTok().getLoc();
if (parseExpression(Offset))
return true;
// We can only deal with constant expressions at the moment.
int64_t OffsetValue;
if (!Offset->evaluateAsAbsolute(OffsetValue))
return Error(OffsetLoc, "expression is not a constant value");
if (Lexer.isNot(AsmToken::Comma))
return TokError("expected comma");
Lexer.Lex();
if (Lexer.isNot(AsmToken::Identifier))
return TokError("expected relocation name");
SMLoc NameLoc = Lexer.getTok().getLoc();
StringRef Name = Lexer.getTok().getIdentifier();
Lexer.Lex();
if (Lexer.is(AsmToken::Comma)) {
Lexer.Lex();
SMLoc ExprLoc = Lexer.getLoc();
if (parseExpression(Expr))
return true;
MCValue Value;
if (!Expr->evaluateAsRelocatable(Value, nullptr, nullptr))
return Error(ExprLoc, "expression must be relocatable");
}
if (Lexer.isNot(AsmToken::EndOfStatement))
return TokError("unexpected token in .reloc directive");
if (getStreamer().EmitRelocDirective(*Offset, Name, Expr, DirectiveLoc))
return Error(NameLoc, "unknown relocation name");
return false;
}
/// parseDirectiveValue
/// ::= (.byte | .short | ... ) [ expression (, expression)* ]
bool AsmParser::parseDirectiveValue(unsigned Size) {
@ -4358,6 +4408,7 @@ void AsmParser::initializeDirectiveKindMap() {
DirectiveKindMap[".err"] = DK_ERR;
DirectiveKindMap[".error"] = DK_ERROR;
DirectiveKindMap[".warning"] = DK_WARNING;
DirectiveKindMap[".reloc"] = DK_RELOC;
}
MCAsmMacro *AsmParser::parseMacroLikeBody(SMLoc DirectiveLoc) {

14
llvm/lib/Target/Mips/MCTargetDesc/MipsAsmBackend.cpp
View File

@ -232,6 +232,18 @@ void MipsAsmBackend::applyFixup(const MCFixup &Fixup, char *Data,
}
}
bool MipsAsmBackend::getFixupKind(StringRef Name, MCFixupKind &MappedKind) const {
if (Name == "R_MIPS_NONE") {
MappedKind = (MCFixupKind)Mips::fixup_Mips_NONE;
return true;
}
if (Name == "R_MIPS_32") {
MappedKind = FK_Data_4;
return true;
}
return MCAsmBackend::getFixupKind(Name, MappedKind);
}
const MCFixupKindInfo &MipsAsmBackend::
getFixupKindInfo(MCFixupKind Kind) const {
const static MCFixupKindInfo LittleEndianInfos[Mips::NumTargetFixupKinds] = {
@ -239,6 +251,7 @@ getFixupKindInfo(MCFixupKind Kind) const {
// MipsFixupKinds.h.
//
// name offset bits flags
{ "fixup_Mips_NONE", 0, 0, 0 },
{ "fixup_Mips_16", 0, 16, 0 },
{ "fixup_Mips_32", 0, 32, 0 },
{ "fixup_Mips_REL32", 0, 32, 0 },
@ -304,6 +317,7 @@ getFixupKindInfo(MCFixupKind Kind) const {
// MipsFixupKinds.h.
//
// name offset bits flags
{ "fixup_Mips_NONE", 0, 0, 0 },
{ "fixup_Mips_16", 16, 16, 0 },
{ "fixup_Mips_32", 0, 32, 0 },
{ "fixup_Mips_REL32", 0, 32, 0 },

1
llvm/lib/Target/Mips/MCTargetDesc/MipsAsmBackend.h
View File

@ -41,6 +41,7 @@ public:
void applyFixup(const MCFixup &Fixup, char *Data, unsigned DataSize,
uint64_t Value, bool IsPCRel) const override;
bool getFixupKind(StringRef Name, MCFixupKind &MappedKind) const override;
const MCFixupKindInfo &getFixupKindInfo(MCFixupKind Kind) const override;
unsigned getNumFixupKinds() const override {

2
llvm/lib/Target/Mips/MCTargetDesc/MipsELFObjectWriter.cpp
View File

@ -68,6 +68,8 @@ unsigned MipsELFObjectWriter::GetRelocType(const MCValue &Target,
unsigned Kind = (unsigned)Fixup.getKind();
switch (Kind) {
case Mips::fixup_Mips_NONE:
return ELF::R_MIPS_NONE;
case Mips::fixup_Mips_16:
case FK_Data_2:
return IsPCRel ? ELF::R_MIPS_PC16 : ELF::R_MIPS_16;

5
llvm/lib/Target/Mips/MCTargetDesc/MipsFixupKinds.h
View File

@ -23,8 +23,11 @@ namespace Mips {
// in MipsAsmBackend.cpp.
//
enum Fixups {
// Branch fixups resulting in R_MIPS_NONE.
fixup_Mips_NONE = FirstTargetFixupKind,
// Branch fixups resulting in R_MIPS_16.
fixup_Mips_16 = FirstTargetFixupKind,
fixup_Mips_16,
// Pure 32 bit data fixup resulting in - R_MIPS_32.
fixup_Mips_32,

6
llvm/test/MC/Mips/reloc-directive-bad.s Normal file
View File

@ -0,0 +1,6 @@
# RUN: not llvm-mc -triple mips-unknown-linux < %s -show-encoding -target-abi=o32 \
# RUN: 2>&1 | FileCheck %s
.text
foo:
.reloc 0, R_MIPS_32, .text+.text # CHECK: :[[@LINE]]:23: error: expression must be relocatable
nop

58
llvm/test/MC/Mips/reloc-directive.s Normal file
View File

@ -0,0 +1,58 @@
# RUN: llvm-mc -triple mips-unknown-linux < %s -show-encoding -target-abi=o32 \
# RUN: | FileCheck -check-prefix=ASM %s
# RUN: llvm-mc -triple mips64-unknown-linux < %s -show-encoding -target-abi=n32 \
# RUN: | FileCheck -check-prefix=ASM %s
# RUN: llvm-mc -triple mips64-unknown-linux < %s -show-encoding -target-abi=n64 \
# RUN: | FileCheck -check-prefix=ASM %s
# RUN: llvm-mc -triple mips-unknown-linux < %s -show-encoding -target-abi=o32 \
# RUN: -filetype=obj | llvm-readobj -sections -section-data -r | \
# RUN: FileCheck -check-prefix=OBJ-O32 %s
# RUN: llvm-mc -triple mips64-unknown-linux < %s -show-encoding -target-abi=n32 \
# RUN: -filetype=obj | llvm-readobj -sections -section-data -r | \
# RUN: FileCheck -check-prefix=OBJ-N32 %s
# RUN: llvm-mc -triple mips64-unknown-linux < %s -show-encoding -target-abi=n64 \
# RUN: -filetype=obj | llvm-readobj -sections -section-data -r | \
# RUN: FileCheck -check-prefix=OBJ-N64 %s
.text
foo:
.reloc 4, R_MIPS_NONE, foo # ASM: .reloc 4, R_MIPS_NONE, foo
.reloc 0, R_MIPS_NONE, foo+4 # ASM: .reloc 0, R_MIPS_NONE, foo+4
.reloc 8, R_MIPS_32, foo+8 # ASM: .reloc 8, R_MIPS_32, foo+8
nop
nop
nop
.reloc 12, R_MIPS_NONE # ASM: .reloc 12, R_MIPS_NONE{{$}}
nop
# OBJ-O32-LABEL: Name: .text
# OBJ-O32: 0000: 00000000 00000000 00000008
# OBJ-O32-LABEL: }
# OBJ-O32-LABEL: Relocations [
# OBJ-O32: 0x0 R_MIPS_NONE foo 0x0
# OBJ-O32: 0x4 R_MIPS_NONE foo 0x0
# OBJ-O32: 0x8 R_MIPS_32 .text 0x0
# OBJ-O32: 0xC R_MIPS_NONE - 0x0
# FIXME: We can't get N32 correct at the moment. If we use a mips-* triple then
# we incorrectly drop the addend. If we use a mips64-* triple then we
# incorrectly use the 3-reloc encoding (and ELF64). mips64-* triples
# are closest to being correct so we use them for now.
# This should be corrected once the triple bugfixes allow us to be ABI
# dependent rather than triple dependent.
# OBJ-N32-LABEL: Name: .text
# OBJ-N32: 0000: 00000000 00000000 00000000
# OBJ-N32-LABEL: }
# OBJ-N32-LABEL: Relocations [
# OBJ-N32: 0x0 R_MIPS_NONE/R_MIPS_NONE/R_MIPS_NONE foo 0x4
# OBJ-N32: 0x4 R_MIPS_NONE/R_MIPS_NONE/R_MIPS_NONE foo 0x0
# OBJ-N32: 0x8 R_MIPS_32/R_MIPS_NONE/R_MIPS_NONE .text 0x8
# OBJ-N32: 0xC R_MIPS_NONE/R_MIPS_NONE/R_MIPS_NONE - 0x0
# OBJ-N64-LABEL: Name: .text
# OBJ-N64: 0000: 00000000 00000000 00000000
# OBJ-N64-LABEL: }
# OBJ-N64-LABEL: Relocations [
# OBJ-N64: 0x0 R_MIPS_NONE/R_MIPS_NONE/R_MIPS_NONE foo 0x4
# OBJ-N64: 0x4 R_MIPS_NONE/R_MIPS_NONE/R_MIPS_NONE foo 0x0
# OBJ-N64: 0x8 R_MIPS_32/R_MIPS_NONE/R_MIPS_NONE .text 0x8
# OBJ-N64: 0xC R_MIPS_NONE/R_MIPS_NONE/R_MIPS_NONE - 0x0