Improve DWARFDebugFrame::parse to also handle __eh_frame.

LLVM MC has single methods which can handle the output of EH frame and DWARF CIE's and FDE's.

This code improves DWARFDebugFrame::parse to do the same for parsing.

This also allows llvm-objdump to support the --dwarf=frames option which objdump supports.  This
option dumps the .eh_frame section using the new code in DWARFDebugFrame::parse.

http://reviews.llvm.org/D15535

Reviewed by Rafael Espindola.

llvm-svn: 256008

llvm/tools/llvm-objdump/llvm-objdump.cpp

@@ -22,6 +22,7 @@
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/ADT/Triple.h"
 #include "llvm/CodeGen/FaultMaps.h"
+#include "llvm/DebugInfo/DWARF/DWARFContext.h"
 #include "llvm/MC/MCAsmInfo.h"
 #include "llvm/MC/MCContext.h"
 #include "llvm/MC/MCDisassembler.h"
@@ -176,6 +177,11 @@ cl::opt<bool>
 cl::opt<bool> PrintFaultMaps("fault-map-section",
                              cl::desc("Display contents of faultmap section"));
 
+cl::opt<DIDumpType> llvm::DwarfDumpType(
+    "dwarf", cl::init(DIDT_Null), cl::desc("Dump of dwarf debug sections:"),
+    cl::values(clEnumValN(DIDT_Frames, "frames", ".debug_frame"),
+               clEnumValEnd));
+
 static StringRef ToolName;
 
 namespace {
@@ -1572,6 +1578,11 @@ static void DumpObject(const ObjectFile *o) {
     printRawClangAST(o);
   if (PrintFaultMaps)
     printFaultMaps(o);
+  if (DwarfDumpType != DIDT_Null) {
+    std::unique_ptr<DIContext> DICtx(new DWARFContextInMemory(*o));
+    // Dump the complete DWARF structure.
+    DICtx->dump(outs(), DwarfDumpType, true /* DumpEH */);
+  }
 }
 
 /// @brief Dump each object file in \a a;
@@ -1664,7 +1675,8 @@ int main(int argc, char **argv) {
       && !(DylibId && MachOOpt)
       && !(ObjcMetaData && MachOOpt)
       && !(FilterSections.size() != 0 && MachOOpt)
-      && !PrintFaultMaps) {
+      && !PrintFaultMaps
+      && DwarfDumpType == DIDT_Null) {
     cl::PrintHelpMessage();
     return 2;
   }