Generate IMAGE_REL_AMD64_ADDR32NB relocations for SEH

 data structures.

The Win64 EH data structures must be of type IMAGE_REL_AMD64_ADDR32NB
instead of IMAGE_REL_AMD64_ADDR32. This is easiely achieved by adding
the VK_COFF_IMGREL32 modifier to the symbol reference.
Change also references to start and end of the SEH range of a function
as offsets to start of the function.

Reviewed by Jim Grosbach, Charles Davis and Nico Rieck.

llvm-svn: 190766

1 files changed, 21 insertions, 5 deletions

diff --git a/llvm/lib/MC/MCWin64EH.cpp b/llvm/lib/MC/MCWin64EH.cpp
index 8db1fa2a93c..c3d568b454c 100644
--- a/llvm/lib/MC/MCWin64EH.cpp
+++ b/llvm/lib/MC/MCWin64EH.cpp
@@ -128,14 +128,29 @@ static void EmitUnwindCode(MCStreamer &streamer, MCSymbol *begin,
   }
 }
 
+static void EmitSymbolRefWithOfs(MCStreamer &streamer,
+                                 const MCSymbol *Base,
+                                 const MCSymbol *Other) {
+  MCContext &Context = streamer.getContext();
+  const MCSymbolRefExpr *BaseRef = MCSymbolRefExpr::Create(Base, Context);
+  const MCSymbolRefExpr *OtherRef = MCSymbolRefExpr::Create(Other, Context);
+  const MCExpr *Ofs = MCBinaryExpr::CreateSub(OtherRef, BaseRef, Context);
+  const MCSymbolRefExpr *BaseRefRel = MCSymbolRefExpr::Create(Base,
+                                              MCSymbolRefExpr::VK_COFF_IMGREL32,
+                                              Context);
+  streamer.EmitValue(MCBinaryExpr::CreateAdd(BaseRefRel, Ofs, Context), 4);
+}
+
 static void EmitRuntimeFunction(MCStreamer &streamer,
                                 const MCWin64EHUnwindInfo *info) {
   MCContext &context = streamer.getContext();
 
   streamer.EmitValueToAlignment(4);
-  streamer.EmitValue(MCSymbolRefExpr::Create(info->Begin, context), 4);
-  streamer.EmitValue(MCSymbolRefExpr::Create(info->End, context), 4);
-  streamer.EmitValue(MCSymbolRefExpr::Create(info->Symbol, context), 4);
+  EmitSymbolRefWithOfs(streamer, info->Function, info->Begin);
+  EmitSymbolRefWithOfs(streamer, info->Function, info->End);
+  streamer.EmitValue(MCSymbolRefExpr::Create(info->Symbol,
+                                             MCSymbolRefExpr::VK_COFF_IMGREL32,
+                                             context), 4);
 }
 
 static void EmitUnwindInfo(MCStreamer &streamer, MCWin64EHUnwindInfo *info) {
@@ -188,8 +203,9 @@ static void EmitUnwindInfo(MCStreamer &streamer, MCWin64EHUnwindInfo *info) {
     EmitRuntimeFunction(streamer, info->ChainedParent);
   else if (flags &
            ((Win64EH::UNW_TerminateHandler|Win64EH::UNW_ExceptionHandler) << 3))
-    streamer.EmitValue(MCSymbolRefExpr::Create(info->ExceptionHandler, context),
-                       4);
+    streamer.EmitValue(MCSymbolRefExpr::Create(info->ExceptionHandler,
+                                              MCSymbolRefExpr::VK_COFF_IMGREL32,
+                                              context), 4);
   else if (numCodes < 2) {
     // The minimum size of an UNWIND_INFO struct is 8 bytes. If we're not
     // a chained unwind info, if there is no handler, and if there are fewer