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

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

diff --git a/include/llvm/Target/TargetLoweringObjectFile.h b/include/llvm/Target/TargetLoweringObjectFile.h
index 57c2606edfa4444ad1a1c0f83577eda270f93a9d..b121fc6bce3b1ae9b4ce2e2201219e30913c13bf 100644 (file)
--- a/include/llvm/Target/TargetLoweringObjectFile.h
+++ b/include/llvm/Target/TargetLoweringObjectFile.h
@@ -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;
   }
 

diff --git a/lib/CodeGen/AsmPrinter/AsmPrinter.cpp b/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
index 569863315ac8ac0645d7949241ebbf37bb038d0b..22eae785c782f55055caffbdad545e209a1fc938 100644 (file)
--- a/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ b/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
@@ -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;

diff --git a/lib/Target/AArch64/AArch64TargetObjectFile.cpp b/lib/Target/AArch64/AArch64TargetObjectFile.cpp
index 4069038dffe70fe343f97237b718ec075a93c95a..3c0a3428ff394c09c059dde87f3a0c5a07f19d25 100644 (file)
--- a/lib/Target/AArch64/AArch64TargetObjectFile.cpp
+++ b/lib/Target/AArch64/AArch64TargetObjectFile.cpp
@@ -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());
+}

diff --git a/lib/Target/AArch64/AArch64TargetObjectFile.h b/lib/Target/AArch64/AArch64TargetObjectFile.h
index 2e595f91961a2ef54d9e49cbb4fa509c34f3b06a..067fda5952b506a7ecdbfc9e58ef22654af63520 100644 (file)
--- a/lib/Target/AArch64/AArch64TargetObjectFile.h
+++ b/lib/Target/AArch64/AArch64TargetObjectFile.h
@@ -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

diff --git a/lib/Target/X86/X86TargetObjectFile.cpp b/lib/Target/X86/X86TargetObjectFile.cpp
index 16ce736588338c0e9bdb92c36222ce4b2c0f6392..15a5fddd8629c46be29d9b427c85a33c5d4ef813 100644 (file)
--- a/lib/Target/X86/X86TargetObjectFile.cpp
+++ b/lib/Target/X86/X86TargetObjectFile.cpp
@@ -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>.

diff --git a/lib/Target/X86/X86TargetObjectFile.h b/lib/Target/X86/X86TargetObjectFile.h
index a92c122838e312a1131d533142455024d87da6e1..3c7caabdfdcac5579289cc94b315048dd5e92778 100644 (file)
--- a/lib/Target/X86/X86TargetObjectFile.h
+++ b/lib/Target/X86/X86TargetObjectFile.h
@@ -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

diff --git a/test/MC/X86/cstexpr-gotpcrel.ll b/test/MC/MachO/cstexpr-gotpcrel-64.ll
similarity index 58%
rename from test/MC/X86/cstexpr-gotpcrel.ll
rename to test/MC/MachO/cstexpr-gotpcrel-64.ll
index 82da87090479e0dc6b4ae59f3f62b49fd1c18fa9..56862fe50738436cf9d4b8d817c51741869c504d 100644 (file)
--- a/test/MC/X86/cstexpr-gotpcrel.ll
+++ b/test/MC/MachO/cstexpr-gotpcrel-64.ll
@@ -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)