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[AsmPrinter][TLOF] ARM64 MachO support for replacing GOT equivalents

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Follow up r230264 and add ARM64 support for replacing global GOT
equivalent symbol accesses by references to the GOT entry for the final
symbol instead, example:

-- before

   .globl  _foo
  _foo:
   .long   42

   .globl  _gotequivalent
  _gotequivalent:
   .quad   _foo

   .globl  _delta
  _delta:
   .long   _gotequivalent-_delta

-- after

   .globl  _foo
  _foo:
   .long   42

   .globl  _delta
  Ltmp3:
   .long _foo@GOT-Ltmp3

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231474 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Bruno Cardoso Lopes 2015-03-06 13:48:45 +00:00
parent a52da9a180
commit 66aa390799
7 changed files with 102 additions and 28 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
include/llvm/Target/TargetLoweringObjectFile.h
View File

@ -43,12 +43,14 @@ class TargetLoweringObjectFile : public MCObjectFileInfo {
protected:
bool SupportIndirectSymViaGOTPCRel;
bool SupportGOTPCRelWithOffset;
public:
MCContext &getContext() const { return *Ctx; }
TargetLoweringObjectFile() : MCObjectFileInfo(), Ctx(nullptr), DL(nullptr),
SupportIndirectSymViaGOTPCRel(false) {}
SupportIndirectSymViaGOTPCRel(false),
SupportGOTPCRelWithOffset(true) {}
virtual ~TargetLoweringObjectFile();
@ -168,9 +170,16 @@ public:
return SupportIndirectSymViaGOTPCRel;
}
/// \brief Target GOT "PC"-relative relocation supports encoding an additional
/// binary expression with an offset?
bool supportGOTPCRelWithOffset() const {
return SupportGOTPCRelWithOffset;
}
/// \brief Get the target specific PC relative GOT entry relocation
virtual const MCExpr *getIndirectSymViaGOTPCRel(const MCSymbol *Sym,
int64_t Offset) const {
int64_t Offset,
MCStreamer &Streamer) const {
return nullptr;
}

7
lib/CodeGen/AsmPrinter/AsmPrinter.cpp
View File

@ -2084,9 +2084,13 @@ static void handleIndirectSymViaGOTPCRel(AsmPrinter &AP, const MCExpr **ME,
//
// gotpcrelcst := <offset from @foo base> + <cst>
//
// Only encode <cst> if the target supports it.
//
int64_t GOTPCRelCst = Offset + MV.getConstant();
if (GOTPCRelCst < 0)
return;
if (!AP.getObjFileLowering().supportGOTPCRelWithOffset() && GOTPCRelCst != 0)
return;
// Emit the GOT PC relative to replace the got equivalent global, i.e.:
//
@ -2110,7 +2114,8 @@ static void handleIndirectSymViaGOTPCRel(AsmPrinter &AP, const MCExpr **ME,
const GlobalValue *FinalGV = dyn_cast<GlobalValue>(GV->getOperand(0));
const MCSymbol *FinalSym = AP.getSymbol(FinalGV);
*ME = AP.getObjFileLowering().getIndirectSymViaGOTPCRel(FinalSym,
GOTPCRelCst);
GOTPCRelCst,
AP.OutStreamer);
// Update GOT equivalent usage information
--NumUses;

18
lib/Target/AArch64/AArch64TargetObjectFile.cpp
View File

@ -23,6 +23,12 @@ void AArch64_ELFTargetObjectFile::Initialize(MCContext &Ctx,
InitializeELF(TM.Options.UseInitArray);
}
AArch64_MachoTargetObjectFile::AArch64_MachoTargetObjectFile()
: TargetLoweringObjectFileMachO() {
SupportIndirectSymViaGOTPCRel = true;
SupportGOTPCRelWithOffset = false;
}
const MCExpr *AArch64_MachoTargetObjectFile::getTTypeGlobalReference(
const GlobalValue *GV, unsigned Encoding, Mangler &Mang,
const TargetMachine &TM, MachineModuleInfo *MMI,
@ -50,3 +56,15 @@ MCSymbol *AArch64_MachoTargetObjectFile::getCFIPersonalitySymbol(
MachineModuleInfo *MMI) const {
return TM.getSymbol(GV, Mang);
}
const MCExpr *AArch64_MachoTargetObjectFile::getIndirectSymViaGOTPCRel(
const MCSymbol *Sym, int64_t Offset, MCStreamer &Streamer) const {
// On ARM64 Darwin, we can reference symbols with foo@GOT-., which
// is an indirect pc-relative reference.
const MCExpr *Res =
MCSymbolRefExpr::Create(Sym, MCSymbolRefExpr::VK_GOT, getContext());
MCSymbol *PCSym = getContext().CreateTempSymbol();
Streamer.EmitLabel(PCSym);
const MCExpr *PC = MCSymbolRefExpr::Create(PCSym, getContext());
return MCBinaryExpr::CreateSub(Res, PC, getContext());
}

6
lib/Target/AArch64/AArch64TargetObjectFile.h
View File

@ -24,6 +24,8 @@ class AArch64_ELFTargetObjectFile : public TargetLoweringObjectFileELF {
/// AArch64_MachoTargetObjectFile - This TLOF implementation is used for Darwin.
class AArch64_MachoTargetObjectFile : public TargetLoweringObjectFileMachO {
public:
AArch64_MachoTargetObjectFile();
const MCExpr *getTTypeGlobalReference(const GlobalValue *GV,
unsigned Encoding, Mangler &Mang,
const TargetMachine &TM,
@ -33,6 +35,10 @@ public:
MCSymbol *getCFIPersonalitySymbol(const GlobalValue *GV, Mangler &Mang,
const TargetMachine &TM,
MachineModuleInfo *MMI) const override;
const MCExpr *
getIndirectSymViaGOTPCRel(const MCSymbol *Sym, int64_t Offset,
MCStreamer &Streamer) const override;
};
} // end namespace llvm

2
lib/Target/X86/X86TargetObjectFile.cpp
View File

@ -52,7 +52,7 @@ MCSymbol *X86_64MachoTargetObjectFile::getCFIPersonalitySymbol(
}
const MCExpr *X86_64MachoTargetObjectFile::getIndirectSymViaGOTPCRel(
const MCSymbol *Sym, int64_t Offset) const {
const MCSymbol *Sym, int64_t Offset, MCStreamer &Streamer) const {
// On Darwin/X86-64, we need to use foo@GOTPCREL+4 to access the got entry
// from a data section. In case there's an additional offset, then use
// foo@GOTPCREL+4+<offset>.

4
lib/Target/X86/X86TargetObjectFile.h
View File

@ -34,8 +34,8 @@ namespace llvm {
MachineModuleInfo *MMI) const override;
const MCExpr *
getIndirectSymViaGOTPCRel(const MCSymbol *Sym,
int64_t Offset) const override;
getIndirectSymViaGOTPCRel(const MCSymbol *Sym, int64_t Offset,
MCStreamer &Streamer) const override;
};
/// \brief This implemenatation is used for X86 ELF targets that don't

80
test/MC/X86/cstexpr-gotpcrel.ll → test/MC/MachO/cstexpr-gotpcrel-64.ll
View File

@ -1,6 +1,9 @@
; RUN: llc -mtriple=x86_64-apple-darwin %s -o %t
; RUN: FileCheck %s < %t
; RUN: FileCheck %s -check-prefix=GOT-EQUIV < %t
; RUN: FileCheck %s -check-prefix=X86 < %t
; RUN: FileCheck %s -check-prefix=X86-GOT-EQUIV < %t
; RUN: llc -mtriple=arm64-apple-darwin %s -o %t
; RUN: FileCheck %s -check-prefix=ARM < %t
; RUN: FileCheck %s -check-prefix=ARM-GOT-EQUIV < %t
; GOT equivalent globals references can be replaced by the GOT entry of the
; final symbol instead.
@ -8,9 +11,15 @@
%struct.data = type { i32, %struct.anon }
%struct.anon = type { i32, i32 }
; Check that these got equivalent symbols are never emitted or used
; GOT-EQUIV-NOT: _localgotequiv
; GOT-EQUIV-NOT: _extgotequiv
; Check that these got equivalent symbols are never emitted on x86-64 and
; emitted on ARM64. Since ARM64 does not support encoding an extra offset with
; @GOT, we still need to emit the equivalents for use by such IR constructs.
; X86-GOT-EQUIV-NOT: L_localgotequiv
; X86-GOT-EQUIV-NOT: l_extgotequiv
; ARM-GOT-EQUIV-LABEL: l_extgotequiv:
; ARM-GOT-EQUIV-LABEL: l_localgotequiv:
@localfoo = global i32 42
@localgotequiv = private unnamed_addr constant i32* @localfoo
@ -21,35 +30,54 @@
; equivalent since it can't be replaced by the GOT entry. @bargotequiv is
; used by an instruction inside @t0.
;
; CHECK: l_bargotequiv:
; CHECK-NEXT: .quad _extbar
; X86: l_bargotequiv:
; X86-NEXT: .quad _extbar
; ARM: l_bargotequiv:
; ARM-NEXT: .quad _extbar
@extbar = external global i32
@bargotequiv = private unnamed_addr constant i32* @extbar
@table = global [4 x %struct.data] [
; CHECK-LABEL: _table
; X86-LABEL: _table
; ARM-LABEL: _table
%struct.data { i32 1, %struct.anon { i32 2, i32 3 } },
; Test GOT equivalent usage inside nested constant arrays.
; CHECK: .long 5
; CHECK-NOT: .long _localgotequiv-(_table+20)
; CHECK-NEXT: .long _localfoo@GOTPCREL+4
; X86: .long 5
; X86-NOT: .long _localgotequiv-(_table+20)
; X86-NEXT: .long _localfoo@GOTPCREL+4
; ARM: .long 5
; ARM-NOT: .long _localgotequiv-(_table+20)
; ARM-NEXT: Ltmp1:
; ARM-NEXT: .long _localfoo@GOT-Ltmp1
%struct.data { i32 4, %struct.anon { i32 5,
i32 trunc (i64 sub (i64 ptrtoint (i32** @localgotequiv to i64),
i64 ptrtoint (i32* getelementptr inbounds ([4 x %struct.data]* @table, i32 0, i64 1, i32 1, i32 1) to i64))
to i32)}
},
; CHECK: .long 5
; CHECK-NOT: _extgotequiv-(_table+32)
; CHECK-NEXT: .long _extfoo@GOTPCREL+4
; X86: .long 5
; X86-NOT: _extgotequiv-(_table+32)
; X86-NEXT: .long _extfoo@GOTPCREL+4
; ARM: .long 5
; ARM-NOT: _extgotequiv-(_table+32)
; ARM-NEXT: Ltmp2:
; ARM-NEXT: _extfoo@GOT-Ltmp2
%struct.data { i32 4, %struct.anon { i32 5,
i32 trunc (i64 sub (i64 ptrtoint (i32** @extgotequiv to i64),
i64 ptrtoint (i32* getelementptr inbounds ([4 x %struct.data]* @table, i32 0, i64 2, i32 1, i32 1) to i64))
to i32)}
},
; Test support for arbitrary constants into the GOTPCREL offset
; CHECK: .long 5
; CHECK-NOT: _extgotequiv-(_table+44)
; CHECK-NEXT: .long _extfoo@GOTPCREL+28
; Test support for arbitrary constants into the GOTPCREL offset, which is
; supported on x86-64 but not on ARM64
; X86: .long 5
; X86-NOT: _extgotequiv-(_table+44)
; X86-NEXT: .long _extfoo@GOTPCREL+28
; ARM: .long 5
; ARM-NEXT: .long (l_extgotequiv-(_table+44))+24
%struct.data { i32 4, %struct.anon { i32 5,
i32 add (i32 trunc (i64 sub (i64 ptrtoint (i32** @extgotequiv to i64),
i64 ptrtoint (i32* getelementptr inbounds ([4 x %struct.data]* @table, i32 0, i64 3, i32 1, i32 1) to i64))
@ -58,14 +86,22 @@
], align 16
; Test multiple uses of GOT equivalents.
; CHECK-LABEL: _delta
; CHECK: .long _extfoo@GOTPCREL+4
; X86-LABEL: _delta
; X86: .long _extfoo@GOTPCREL+4
; ARM-LABEL: _delta
; ARM: Ltmp3:
; ARM-NEXT: .long _extfoo@GOT-Ltmp3
@delta = global i32 trunc (i64 sub (i64 ptrtoint (i32** @extgotequiv to i64),
i64 ptrtoint (i32* @delta to i64))
to i32)
; CHECK-LABEL: _deltaplus:
; CHECK: .long _localfoo@GOTPCREL+59
; X86-LABEL: _deltaplus:
; X86: .long _localfoo@GOTPCREL+59
; ARM-LABEL: _deltaplus:
; ARM: .long (l_localgotequiv-_deltaplus)+55
@deltaplus = global i32 add (i32 trunc (i64 sub (i64 ptrtoint (i32** @localgotequiv to i64),
i64 ptrtoint (i32* @deltaplus to i64))
to i32), i32 55)