MCCodeEmitter: Add target independent fixup flag for is-pc-relative.

llvm-svn: 98954

llvm/include/llvm/MC/MCCodeEmitter.h

@@ -22,6 +22,12 @@ template<typename T> class SmallVectorImpl;
 
 /// MCFixupKindInfo - Target independent information on a fixup kind.
 struct MCFixupKindInfo {
+  enum FixupKindFlags {
+    /// Is this fixup kind PCrelative. This is used by the assembler backend to
+    /// evaluate fixup values in a target independent manner when possible.
+    FKF_IsPCRel = (1 << 0)
+  };
+
   /// A target specific name for the fixup kind. The names will be unique for
   /// distinct kinds on any given target.
   const char *Name;
@@ -36,6 +42,9 @@ struct MCFixupKindInfo {
   /// The number of bits written by this fixup. The bits are assumed to be
   /// contiguous.
   unsigned TargetSize;
+
+  /// Flags describing additional information on this fixup kind.
+  unsigned Flags;
 };
 
 /// MCCodeEmitter - Generic instruction encoding interface.

llvm/lib/MC/MCAssembler.cpp

@@ -10,6 +10,7 @@
 #define DEBUG_TYPE "assembler"
 #include "llvm/MC/MCAssembler.h"
 #include "llvm/MC/MCAsmLayout.h"
+#include "llvm/MC/MCCodeEmitter.h"
 #include "llvm/MC/MCExpr.h"
 #include "llvm/MC/MCObjectWriter.h"
 #include "llvm/MC/MCSymbol.h"
@@ -37,17 +38,6 @@ STATISTIC(EmittedFragments, "Number of emitted assembler fragments");
 // object file, which may truncate it. We should detect that truncation where
 // invalid and report errors back.
 
-static bool isFixupKindPCRel(unsigned Kind) {
-  switch (Kind) {
-  default:
-    return false;
-  case X86::reloc_pcrel_1byte:
-  case X86::reloc_pcrel_4byte:
-  case X86::reloc_riprel_4byte:
-    return true;
-  }
-}
-
 /* *** */
 
 MCFragment::MCFragment() : Kind(FragmentType(~0)) {
@@ -258,7 +248,9 @@ bool MCAssembler::EvaluateFixup(const MCAsmLayout &Layout, MCAsmFixup &Fixup,
 
   Value = Target.getConstant();
 
-  bool IsResolved = true, IsPCRel = isFixupKindPCRel(Fixup.Kind);
+  bool IsPCRel =
+    Emitter.getFixupKindInfo(Fixup.Kind).Flags & MCFixupKindInfo::FKF_IsPCRel;
+  bool IsResolved = true;
   if (const MCSymbolRefExpr *A = Target.getSymA()) {
     if (A->getSymbol().isDefined())
       Value += getSymbolData(A->getSymbol()).getAddress();

llvm/lib/MC/MCCodeEmitter.cpp

@@ -19,10 +19,10 @@ MCCodeEmitter::~MCCodeEmitter() {
 
 const MCFixupKindInfo &MCCodeEmitter::getFixupKindInfo(MCFixupKind Kind) const {
   static const MCFixupKindInfo Builtins[] = {
-    { "FK_Data_1", 0, 8 },
-    { "FK_Data_2", 0, 16 },
-    { "FK_Data_4", 0, 32 },
-    { "FK_Data_8", 0, 64 }
+    { "FK_Data_1", 0, 8, 0 },
+    { "FK_Data_2", 0, 16, 0 },
+    { "FK_Data_4", 0, 32, 0 },
+    { "FK_Data_8", 0, 64, 0 }
   };
   
   assert(Kind <= 3 && "Unknown fixup kind");

llvm/lib/Target/X86/X86MCCodeEmitter.cpp

@@ -43,10 +43,10 @@ public:
 
   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_movq_load", 0, 4 * 8 }
+      { "reloc_pcrel_4byte", 0, 4 * 8, MCFixupKindInfo::FKF_IsPCRel },
+      { "reloc_pcrel_1byte", 0, 1 * 8, MCFixupKindInfo::FKF_IsPCRel },
+      { "reloc_riprel_4byte", 0, 4 * 8, MCFixupKindInfo::FKF_IsPCRel },
+      { "reloc_riprel_4byte_movq_load", 0, 4 * 8, MCFixupKindInfo::FKF_IsPCRel }
     };
     
     if (Kind < FirstTargetFixupKind)