make pcrel immediate values relative to the start of the field,
not the end of the field, fixing rdar://7651978
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@96330 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/X86MCCodeEmitter.cpp b/lib/Target/X86/X86MCCodeEmitter.cpp
index d0ec0de..3f18696 100644
--- a/lib/Target/X86/X86MCCodeEmitter.cpp
+++ b/lib/Target/X86/X86MCCodeEmitter.cpp
@@ -153,14 +153,25 @@
// If this is a simple integer displacement that doesn't require a relocation,
// emit it now.
if (DispOp.isImm()) {
+ // FIXME: is this right for pc-rel encoding?? Probably need to emit this as
+ // a fixup if so.
EmitConstant(DispOp.getImm()+ImmOffset, Size, CurByte, OS);
return;
}
// If we have an immoffset, add it to the expression.
const MCExpr *Expr = DispOp.getExpr();
+
+ // If the fixup is pc-relative, we need to bias the value to be relative to
+ // the start of the field, not the end of the field.
+ if (FixupKind == MCFixupKind(X86::reloc_pcrel_4byte) ||
+ FixupKind == MCFixupKind(X86::reloc_riprel_4byte))
+ ImmOffset -= 4;
+ if (FixupKind == MCFixupKind(X86::reloc_pcrel_1byte))
+ ImmOffset -= 1;
+
if (ImmOffset)
- Expr = MCBinaryExpr::CreateAdd(Expr,MCConstantExpr::Create(ImmOffset, Ctx),
+ Expr = MCBinaryExpr::CreateAdd(Expr, MCConstantExpr::Create(ImmOffset, Ctx),
Ctx);
// Emit a symbolic constant as a fixup and 4 zeros.
@@ -192,6 +203,7 @@
// the size of the immediate field. If we have this case, add it into the
// expression to emit.
int ImmSize = X86II::hasImm(TSFlags) ? X86II::getSizeOfImm(TSFlags) : 0;
+
EmitImmediate(Disp, 4, MCFixupKind(X86::reloc_riprel_4byte),
CurByte, OS, Fixups, -ImmSize);
return;
@@ -616,8 +628,6 @@
// If there is a remaining operand, it must be a trailing immediate. Emit it
// according to the right size for the instruction.
- // FIXME: This should pass in whether the value is pc relative or not. This
- // information should be aquired from TSFlags as well.
if (CurOp != NumOps)
EmitImmediate(MI.getOperand(CurOp++),
X86II::getSizeOfImm(TSFlags), getImmFixupKind(TSFlags),