Reland "[DebugInfo] Support DWARF expressions in eh_frame"

Summary:
Original change was D43313 (r326932) and reverted by r326953 because it
broke an LLD test and a windows build. The LLD test was already fixed in
lld commit r326944 (thanks maskray). This is the original change with
the windows build fixed.

llvm-svn: 326970

1 files changed, 6 insertions, 0 deletions

diff --git a/llvm/tools/llvm-readobj/ELFDumper.cpp b/llvm/tools/llvm-readobj/ELFDumper.cpp
index 36cda459225..6b6582b7566 100644
--- a/llvm/tools/llvm-readobj/ELFDumper.cpp
+++ b/llvm/tools/llvm-readobj/ELFDumper.cpp
@@ -13,6 +13,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "ARMEHABIPrinter.h"
+#include "DwarfCFIEHPrinter.h"
 #include "Error.h"
 #include "ObjDumper.h"
 #include "StackMapPrinter.h"
@@ -1808,6 +1809,11 @@ void ELFDumper<ELFT>::printValue(uint64_t Type, uint64_t Value) {
 
 template<class ELFT>
 void ELFDumper<ELFT>::printUnwindInfo() {
+  const unsigned Machine = Obj->getHeader()->e_machine;
+  if (Machine == EM_386 || Machine == EM_X86_64) {
+    DwarfCFIEH::PrinterContext<ELFT> Ctx(W, Obj);
+    return Ctx.printUnwindInformation();
+  }
   W.startLine() << "UnwindInfo not implemented.\n";
 }