Revert 122160 while I debug it.

[oota-llvm.git] / lib / MC / MachObjectWriter.cpp

diff --git a/lib/MC/MachObjectWriter.cpp b/lib/MC/MachObjectWriter.cpp
index e12daa708bcdc8b15f17078c5d3a05554ed77b1c..11681ca90b162775d263e7d8529a4e3451c3d086 100644 (file)
--- a/lib/MC/MachObjectWriter.cpp
+++ b/lib/MC/MachObjectWriter.cpp
@@ -1125,7 +1125,39 @@ public:
 
   bool IsSymbolRefDifferenceFullyResolved(const MCAssembler &Asm,
                                           const MCSymbolRefExpr *A,
-                                          const MCSymbolRefExpr *B) const {
+                                          const MCSymbolRefExpr *B,
+                                          bool InSet) const {
+    if (InSet)
+      return true;
+
+    if (!TargetObjectWriter->useAggressiveSymbolFolding())
+      return false;
+
+    // The effective address is
+    //     addr(atom(A)) + offset(A)
+    //   - addr(atom(B)) - offset(B)
+    // and the offsets are not relocatable, so the fixup is fully resolved when
+    //  addr(atom(A)) - addr(atom(B)) == 0.
+    const MCSymbolData *A_Base = 0, *B_Base = 0;
+
+    // Modified symbol references cannot be resolved.
+    if (A->getKind() != MCSymbolRefExpr::VK_None ||
+        B->getKind() != MCSymbolRefExpr::VK_None)
+      return false;
+
+    A_Base = Asm.getAtom(&Asm.getSymbolData(A->getSymbol()));
+    if (!A_Base)
+      return false;
+
+    B_Base = Asm.getAtom(&Asm.getSymbolData(B->getSymbol()));
+    if (!B_Base)
+      return false;
+
+    // If the atoms are the same, they are guaranteed to have the same address.
+    if (A_Base == B_Base)
+      return true;
+
+    // Otherwise, we can't prove this is fully resolved.
     return false;
   }