add a special relocation type for movq loads for object

[oota-llvm.git] / lib / Target / X86 / X86MCCodeEmitter.cpp

diff --git a/lib/Target/X86/X86MCCodeEmitter.cpp b/lib/Target/X86/X86MCCodeEmitter.cpp
index 3f18696d8555c5f3b3d779407050f8a28e2c5d68..4547a3a33138e6534d063ce5604cc92d06a70b7a 100644 (file)
--- a/lib/Target/X86/X86MCCodeEmitter.cpp
+++ b/lib/Target/X86/X86MCCodeEmitter.cpp
@@ -38,14 +38,15 @@ public:
   ~X86MCCodeEmitter() {}
 
   unsigned getNumFixupKinds() const {
-    return 3;
+    return 4;
   }
 
   const MCFixupKindInfo &getFixupKindInfo(MCFixupKind Kind) const {
     const static MCFixupKindInfo Infos[] = {
       { "reloc_pcrel_4byte", 0, 4 * 8 },
       { "reloc_pcrel_1byte", 0, 1 * 8 },
-      { "reloc_riprel_4byte", 0, 4 * 8 }
+      { "reloc_riprel_4byte", 0, 4 * 8 },
+      { "reloc_riprel_4byte_movq_load", 0, 4 * 8 }
     };
     
     if (Kind < FirstTargetFixupKind)
@@ -197,6 +198,14 @@ void X86MCCodeEmitter::EmitMemModRMByte(const MCInst &MI, unsigned Op,
            "Invalid rip-relative address");
     EmitByte(ModRMByte(0, RegOpcodeField, 5), CurByte, OS);
     
+    unsigned FixupKind = X86::reloc_riprel_4byte;
+    
+    // movq loads are handled with a special relocation form which allows the
+    // linker to eliminate some loads for GOT references which end up in the
+    // same linkage unit.
+    if (MI.getOpcode() == X86::MOV64rm_TC)
+      FixupKind = X86::reloc_riprel_4byte_movq_load;
+    
     // rip-relative addressing is actually relative to the *next* instruction.
     // Since an immediate can follow the mod/rm byte for an instruction, this
     // means that we need to bias the immediate field of the instruction with
@@ -204,7 +213,7 @@ void X86MCCodeEmitter::EmitMemModRMByte(const MCInst &MI, unsigned Op,
     // expression to emit.
     int ImmSize = X86II::hasImm(TSFlags) ? X86II::getSizeOfImm(TSFlags) : 0;
     
-    EmitImmediate(Disp, 4, MCFixupKind(X86::reloc_riprel_4byte),
+    EmitImmediate(Disp, 4, MCFixupKind(FixupKind),
                   CurByte, OS, Fixups, -ImmSize);
     return;
   }