MC: Support COFF image-relative MCSymbolRefs
Add support for the COFF relocation types IMAGE_REL_I386_DIR32NB and
IMAGE_REL_AMD64_ADDR32NB for 32- and 64-bit respectively. These are
similar to normal 4-byte relocations except that they do not include
the base address of the image.
Image-relative relocations are used for debug information (32-bit) and
SEH unwind tables (64-bit).
A new MCSymbolRef variant called 'VK_COFF_IMGREL32' is introduced to
specify such relocations. For AT&T assembly, this variant can be accessed
using the symbol suffix '@imgrel'.
llvm-svn: 179240
diff --git a/llvm/lib/Target/X86/MCTargetDesc/X86WinCOFFObjectWriter.cpp b/llvm/lib/Target/X86/MCTargetDesc/X86WinCOFFObjectWriter.cpp
index bc272ef..ed64a32 100644
--- a/llvm/lib/Target/X86/MCTargetDesc/X86WinCOFFObjectWriter.cpp
+++ b/llvm/lib/Target/X86/MCTargetDesc/X86WinCOFFObjectWriter.cpp
@@ -9,6 +9,8 @@
#include "MCTargetDesc/X86FixupKinds.h"
#include "MCTargetDesc/X86MCTargetDesc.h"
+#include "llvm/MC/MCExpr.h"
+#include "llvm/MC/MCValue.h"
#include "llvm/MC/MCWinCOFFObjectWriter.h"
#include "llvm/Support/COFF.h"
#include "llvm/Support/ErrorHandling.h"
@@ -27,7 +29,9 @@
X86WinCOFFObjectWriter(bool Is64Bit_);
~X86WinCOFFObjectWriter();
- virtual unsigned getRelocType(unsigned FixupKind) const;
+ virtual unsigned getRelocType(const MCValue &Target,
+ const MCFixup &Fixup,
+ bool IsCrossSection) const LLVM_OVERRIDE;
};
}
@@ -38,7 +42,14 @@
X86WinCOFFObjectWriter::~X86WinCOFFObjectWriter() {}
-unsigned X86WinCOFFObjectWriter::getRelocType(unsigned FixupKind) const {
+unsigned X86WinCOFFObjectWriter::getRelocType(const MCValue &Target,
+ const MCFixup &Fixup,
+ bool IsCrossSection) const {
+ unsigned FixupKind = IsCrossSection ? FK_PCRel_4 : Fixup.getKind();
+
+ MCSymbolRefExpr::VariantKind Modifier = Target.isAbsolute() ?
+ MCSymbolRefExpr::VK_None : Target.getSymA()->getKind();
+
switch (FixupKind) {
case FK_PCRel_4:
case X86::reloc_riprel_4byte:
@@ -46,6 +57,9 @@
return Is64Bit ? COFF::IMAGE_REL_AMD64_REL32 : COFF::IMAGE_REL_I386_REL32;
case FK_Data_4:
case X86::reloc_signed_4byte:
+ if (Modifier == MCSymbolRefExpr::VK_COFF_IMGREL32)
+ return Is64Bit ? COFF::IMAGE_REL_AMD64_ADDR32NB :
+ COFF::IMAGE_REL_I386_DIR32NB;
return Is64Bit ? COFF::IMAGE_REL_AMD64_ADDR32 : COFF::IMAGE_REL_I386_DIR32;
case FK_Data_8:
if (Is64Bit)