1 files changed, 56 insertions, 22 deletions

diff --git a/llvm/lib/Target/X86/MCTargetDesc/X86AsmBackend.cpp b/llvm/lib/Target/X86/MCTargetDesc/X86AsmBackend.cpp
index 95012a148d83..83f3614ded1a 100644
--- a/llvm/lib/Target/X86/MCTargetDesc/X86AsmBackend.cpp
+++ b/llvm/lib/Target/X86/MCTargetDesc/X86AsmBackend.cpp
@@ -680,12 +680,21 @@ Optional<MCFixupKind> X86AsmBackend::getFixupKind(StringRef Name) const {
 #define ELF_RELOC(X, Y) .Case(#X, Y)
 #include "llvm/BinaryFormat/ELFRelocs/x86_64.def"
 #undef ELF_RELOC
+                 .Case("BFD_RELOC_NONE", ELF::R_X86_64_NONE)
+                 .Case("BFD_RELOC_8", ELF::R_X86_64_8)
+                 .Case("BFD_RELOC_16", ELF::R_X86_64_16)
+                 .Case("BFD_RELOC_32", ELF::R_X86_64_32)
+                 .Case("BFD_RELOC_64", ELF::R_X86_64_64)
                  .Default(-1u);
     } else {
       Type = llvm::StringSwitch<unsigned>(Name)
 #define ELF_RELOC(X, Y) .Case(#X, Y)
 #include "llvm/BinaryFormat/ELFRelocs/i386.def"
 #undef ELF_RELOC
+                 .Case("BFD_RELOC_NONE", ELF::R_386_NONE)
+                 .Case("BFD_RELOC_8", ELF::R_386_8)
+                 .Case("BFD_RELOC_16", ELF::R_386_16)
+                 .Case("BFD_RELOC_32", ELF::R_386_32)
                  .Default(-1u);
     }
     if (Type == -1u)
@@ -1073,6 +1082,8 @@ void X86AsmBackend::finishLayout(MCAssembler const &Asm,
 }
 
 unsigned X86AsmBackend::getMaximumNopSize() const {
+  if (STI.hasFeature(X86::Mode16Bit))
+    return 4;
   if (!STI.hasFeature(X86::FeatureNOPL) && !STI.hasFeature(X86::Mode64Bit))
     return 1;
   if (STI.getFeatureBits()[X86::FeatureFast7ByteNOP])
@@ -1091,29 +1102,44 @@ unsigned X86AsmBackend::getMaximumNopSize() const {
 /// bytes.
 /// \return - true on success, false on failure
 bool X86AsmBackend::writeNopData(raw_ostream &OS, uint64_t Count) const {
-  static const char Nops[10][11] = {
-    // nop
-    "\x90",
-    // xchg %ax,%ax
-    "\x66\x90",
-    // nopl (%[re]ax)
-    "\x0f\x1f\x00",
-    // nopl 0(%[re]ax)
-    "\x0f\x1f\x40\x00",
-    // nopl 0(%[re]ax,%[re]ax,1)
-    "\x0f\x1f\x44\x00\x00",
-    // nopw 0(%[re]ax,%[re]ax,1)
-    "\x66\x0f\x1f\x44\x00\x00",
-    // nopl 0L(%[re]ax)
-    "\x0f\x1f\x80\x00\x00\x00\x00",
-    // nopl 0L(%[re]ax,%[re]ax,1)
-    "\x0f\x1f\x84\x00\x00\x00\x00\x00",
-    // nopw 0L(%[re]ax,%[re]ax,1)
-    "\x66\x0f\x1f\x84\x00\x00\x00\x00\x00",
-    // nopw %cs:0L(%[re]ax,%[re]ax,1)
-    "\x66\x2e\x0f\x1f\x84\x00\x00\x00\x00\x00",
+  static const char Nops32Bit[10][11] = {
+      // nop
+      "\x90",
+      // xchg %ax,%ax
+      "\x66\x90",
+      // nopl (%[re]ax)
+      "\x0f\x1f\x00",
+      // nopl 0(%[re]ax)
+      "\x0f\x1f\x40\x00",
+      // nopl 0(%[re]ax,%[re]ax,1)
+      "\x0f\x1f\x44\x00\x00",
+      // nopw 0(%[re]ax,%[re]ax,1)
+      "\x66\x0f\x1f\x44\x00\x00",
+      // nopl 0L(%[re]ax)
+      "\x0f\x1f\x80\x00\x00\x00\x00",
+      // nopl 0L(%[re]ax,%[re]ax,1)
+      "\x0f\x1f\x84\x00\x00\x00\x00\x00",
+      // nopw 0L(%[re]ax,%[re]ax,1)
+      "\x66\x0f\x1f\x84\x00\x00\x00\x00\x00",
+      // nopw %cs:0L(%[re]ax,%[re]ax,1)
+      "\x66\x2e\x0f\x1f\x84\x00\x00\x00\x00\x00",
+  };
+
+  // 16-bit mode uses different nop patterns than 32-bit.
+  static const char Nops16Bit[4][11] = {
+      // nop
+      "\x90",
+      // xchg %eax,%eax
+      "\x66\x90",
+      // lea 0(%si),%si
+      "\x8d\x74\x00",
+      // lea 0w(%si),%si
+      "\x8d\xb4\x00\x00",
   };
 
+  const char(*Nops)[11] =
+      STI.getFeatureBits()[X86::Mode16Bit] ? Nops16Bit : Nops32Bit;
+
   uint64_t MaxNopLength = (uint64_t)getMaximumNopSize();
 
   // Emit as many MaxNopLength NOPs as needed, then emit a NOP of the remaining
@@ -1428,6 +1454,7 @@ public:
     unsigned StackAdjust = 0;
     unsigned StackSize = 0;
     unsigned NumDefCFAOffsets = 0;
+    int MinAbsOffset = std::numeric_limits<int>::max();
 
     for (unsigned i = 0, e = Instrs.size(); i != e; ++i) {
       const MCCFIInstruction &Inst = Instrs[i];
@@ -1456,6 +1483,7 @@ public:
         memset(SavedRegs, 0, sizeof(SavedRegs));
         StackAdjust = 0;
         SavedRegIdx = 0;
+        MinAbsOffset = std::numeric_limits<int>::max();
         InstrOffset += MoveInstrSize;
         break;
       }
@@ -1499,6 +1527,7 @@ public:
         unsigned Reg = *MRI.getLLVMRegNum(Inst.getRegister(), true);
         SavedRegs[SavedRegIdx++] = Reg;
         StackAdjust += OffsetSize;
+        MinAbsOffset = std::min(MinAbsOffset, abs(Inst.getOffset()));
         InstrOffset += PushInstrSize(Reg);
         break;
       }
@@ -1512,6 +1541,11 @@ public:
         // Offset was too big for a compact unwind encoding.
         return CU::UNWIND_MODE_DWARF;
 
+      // We don't attempt to track a real StackAdjust, so if the saved registers
+      // aren't adjacent to rbp we can't cope.
+      if (SavedRegIdx != 0 && MinAbsOffset != 3 * (int)OffsetSize)
+        return CU::UNWIND_MODE_DWARF;
+
       // Get the encoding of the saved registers when we have a frame pointer.
       uint32_t RegEnc = encodeCompactUnwindRegistersWithFrame();
       if (RegEnc == ~0U) return CU::UNWIND_MODE_DWARF;
@@ -1597,7 +1631,7 @@ MCAsmBackend *llvm::createX86_64AsmBackend(const Target &T,
 
   uint8_t OSABI = MCELFObjectTargetWriter::getOSABI(TheTriple.getOS());
 
-  if (TheTriple.getEnvironment() == Triple::GNUX32)
+  if (TheTriple.isX32())
     return new ELFX86_X32AsmBackend(T, OSABI, STI);
   return new ELFX86_64AsmBackend(T, OSABI, STI);
 }