Reapply 132424 with fixes. This fixes PR10068.

[oota-llvm.git] / lib / Target / X86 / X86AsmBackend.cpp

diff --git a/lib/Target/X86/X86AsmBackend.cpp b/lib/Target/X86/X86AsmBackend.cpp
index c39d07b12ed60e654a022a2215616f4f0bc1304e..4d7d96dcb36bd9150ceae86304626bab8a6bd936 100644 (file)
--- a/lib/Target/X86/X86AsmBackend.cpp
+++ b/lib/Target/X86/X86AsmBackend.cpp
@@ -21,6 +21,7 @@
 #include "llvm/MC/MCSectionELF.h"
 #include "llvm/MC/MCSectionMachO.h"
 #include "llvm/Object/MachOFormat.h"
+#include "llvm/Support/CommandLine.h"
 #include "llvm/Support/ELF.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/raw_ostream.h"
@@ -28,6 +29,13 @@
 #include "llvm/Target/TargetAsmBackend.h"
 using namespace llvm;
 
+// Option to allow disabling arithmetic relaxation to workaround PR9807, which
+// is useful when running bitwise comparison experiments on Darwin. We should be
+// able to remove this once PR9807 is resolved.
+static cl::opt<bool>
+MCDisableArithRelaxation("mc-x86-disable-arith-relaxation",
+         cl::desc("Disable relaxation of arithmetic instruction for X86"));
+
 static unsigned getFixupKindLog2Size(unsigned Kind) {
   switch (Kind) {
   default: assert(0 && "invalid fixup kind!");
@@ -41,18 +49,12 @@ static unsigned getFixupKindLog2Size(unsigned Kind) {
   case X86::reloc_signed_4byte:
   case X86::reloc_global_offset_table:
   case FK_Data_4: return 2;
+  case FK_PCRel_8:
   case FK_Data_8: return 3;
   }
 }
 
 namespace {
-class X86MachObjectWriter : public MCMachObjectTargetWriter {
-public:
-  X86MachObjectWriter(bool Is64Bit, uint32_t CPUType,
-                      uint32_t CPUSubtype)
-    : MCMachObjectTargetWriter(Is64Bit, CPUType, CPUSubtype,
-                               /*UseAggressiveSymbolFolding=*/Is64Bit) {}
-};
 
 class X86ELFObjectWriter : public MCELFObjectTargetWriter {
 public:
@@ -207,6 +209,9 @@ bool X86AsmBackend::MayNeedRelaxation(const MCInst &Inst) const {
   if (getRelaxedOpcodeBranch(Inst.getOpcode()) != Inst.getOpcode())
     return true;
 
+  if (MCDisableArithRelaxation)
+    return false;
+
   // Check if this instruction is ever relaxable.
   if (getRelaxedOpcodeArith(Inst.getOpcode()) == Inst.getOpcode())
     return false;
@@ -303,7 +308,7 @@ public:
 
   virtual bool doesSectionRequireSymbols(const MCSection &Section) const {
     const MCSectionELF &ES = static_cast<const MCSectionELF&>(Section);
-    return ES.getFlags() & MCSectionELF::SHF_MERGE;
+    return ES.getFlags() & ELF::SHF_MERGE;
   }
 };
 
@@ -313,10 +318,13 @@ public:
     : ELFX86AsmBackend(T, OSType) {}
 
   MCObjectWriter *createObjectWriter(raw_ostream &OS) const {
-    return createELFObjectWriter(new X86ELFObjectWriter(false, OSType,
-                                                        ELF::EM_386, false),
+    return createELFObjectWriter(createELFObjectTargetWriter(),
                                  OS, /*IsLittleEndian*/ true);
   }
+
+  MCELFObjectTargetWriter *createELFObjectTargetWriter() const {
+    return new X86ELFObjectWriter(false, OSType, ELF::EM_386, false);
+  }
 };
 
 class ELFX86_64AsmBackend : public ELFX86AsmBackend {
@@ -325,10 +333,13 @@ public:
     : ELFX86AsmBackend(T, OSType) {}
 
   MCObjectWriter *createObjectWriter(raw_ostream &OS) const {
-    return createELFObjectWriter(new X86ELFObjectWriter(true, OSType,
-                                                        ELF::EM_X86_64, true),
+    return createELFObjectWriter(createELFObjectTargetWriter(),
                                  OS, /*IsLittleEndian*/ true);
   }
+
+  MCELFObjectTargetWriter *createELFObjectTargetWriter() const {
+    return new X86ELFObjectWriter(true, OSType, ELF::EM_X86_64, true);
+  }
 };
 
 class WindowsX86AsmBackend : public X86AsmBackend {
@@ -357,11 +368,9 @@ public:
     : DarwinX86AsmBackend(T) {}
 
   MCObjectWriter *createObjectWriter(raw_ostream &OS) const {
-    return createMachObjectWriter(new X86MachObjectWriter(
-                                    /*Is64Bit=*/false,
-                                    object::mach::CTM_i386,
-                                    object::mach::CSX86_ALL),
-                                  OS, /*IsLittleEndian=*/true);
+    return createX86MachObjectWriter(OS, /*Is64Bit=*/false,
+                                     object::mach::CTM_i386,
+                                     object::mach::CSX86_ALL);
   }
 };
 
@@ -373,11 +382,9 @@ public:
   }
 
   MCObjectWriter *createObjectWriter(raw_ostream &OS) const {
-    return createMachObjectWriter(new X86MachObjectWriter(
-                                    /*Is64Bit=*/true,
-                                    object::mach::CTM_x86_64,
-                                    object::mach::CSX86_ALL),
-                                  OS, /*IsLittleEndian=*/true);
+    return createX86MachObjectWriter(OS, /*Is64Bit=*/true,
+                                     object::mach::CTM_x86_64,
+                                     object::mach::CSX86_ALL);
   }
 
   virtual bool doesSectionRequireSymbols(const MCSection &Section) const {
@@ -418,28 +425,26 @@ public:
 
 TargetAsmBackend *llvm::createX86_32AsmBackend(const Target &T,
                                                const std::string &TT) {
-  switch (Triple(TT).getOS()) {
-  case Triple::Darwin:
+  Triple TheTriple(TT);
+
+  if (TheTriple.isOSDarwin() || TheTriple.getEnvironment() == Triple::MachO)
     return new DarwinX86_32AsmBackend(T);
-  case Triple::MinGW32:
-  case Triple::Cygwin:
-  case Triple::Win32:
+
+  if (TheTriple.isOSWindows())
     return new WindowsX86AsmBackend(T, false);
-  default:
-    return new ELFX86_32AsmBackend(T, Triple(TT).getOS());
-  }
+
+  return new ELFX86_32AsmBackend(T, TheTriple.getOS());
 }
 
 TargetAsmBackend *llvm::createX86_64AsmBackend(const Target &T,
                                                const std::string &TT) {
-  switch (Triple(TT).getOS()) {
-  case Triple::Darwin:
+  Triple TheTriple(TT);
+
+  if (TheTriple.isOSDarwin() || TheTriple.getEnvironment() == Triple::MachO)
     return new DarwinX86_64AsmBackend(T);
-  case Triple::MinGW64:
-  case Triple::Cygwin:
-  case Triple::Win32:
+
+  if (TheTriple.isOSWindows())
     return new WindowsX86AsmBackend(T, true);
-  default:
-    return new ELFX86_64AsmBackend(T, Triple(TT).getOS());
-  }
+
+  return new ELFX86_64AsmBackend(T, TheTriple.getOS());
 }