[llvm-dwarfdump] Brief mode only dumps debug_info by default

[JDevlieghere]

Summary

This patch changes the default behavior in brief mode to only show the
debug_info section. This is undoubtedly the most popular and likely the
one you'd want in brief mode.

Non-brief mode behavior is not affected and still defaults to all.

[JDevlieghere]

@dblaikie: I've added the positive tests you mentioned in D36835 as I was changing the file anyway. I also like the idea of omitting the prefixes in brief mode, but that's definitely something for a separate differential.

[JDevlieghere]

Improved test as suggested by @dblaikie

llvm/trunk/test/tools/llvm-dwarfdump/X86/brief.s

 # RUN: llvm-mc %s -filetype obj -triple x86_64-apple-darwin -o - \
 # RUN: | llvm-dwarfdump -debug-dump=info -brief - \
 # RUN: | FileCheck %s
 
+# CHECK-NOT: .debug_abbrev contents:
+#
+# CHECK: .debug_info contents:
 # CHECK: DW_TAG_compile_unit
 # CHECK-NOT: DW_FORM
-# CHECK: DW_AT
+# CHECK: DW_AT_name        ("brief.c")
+# CHECK: DW_AT_name      ("main")
+# CHECK: DW_AT_name      ("int")
 # CHECK-NOT: debug_str
 # CHECK-NOT: DW_AT_type {{.*}} =>
-
+#
+# CHECK-NOT: {{.*}} contents:
+#
 # This test is meant to verify that -brief hides DW_FORMs and abbreviation
 # codes from .debug_info section. Furthermore it verifies that it also hides
 # .debug_str and die reference offsets into the CU.
 
   .section  __TEXT,__text,regular,pure_instructions
   .macosx_version_min 10, 12
   .globl  _main                   ## -- Begin function main
   .p2align  4, 0x90

llvm/trunk/tools/llvm-dwarfdump/llvm-dwarfdump.cpp

 using namespace llvm;
 using namespace object;
 
 static cl::list<std::string>
 InputFilenames(cl::Positional, cl::desc("<input object files or .dSYM bundles>"),
                cl::ZeroOrMore);
 
 static cl::opt<DIDumpType> DumpType(
-    "debug-dump", cl::init(DIDT_All), cl::desc("Dump of debug sections:"),
+    "debug-dump", cl::init(DIDT_Null), cl::desc("Dump of debug sections:"),
     cl::values(
         clEnumValN(DIDT_All, "all", "Dump all debug sections"),
         clEnumValN(DIDT_Abbrev, "abbrev", ".debug_abbrev"),
         clEnumValN(DIDT_AbbrevDwo, "abbrev.dwo", ".debug_abbrev.dwo"),
         clEnumValN(DIDT_AppleNames, "apple_names", ".apple_names"),
         clEnumValN(DIDT_AppleTypes, "apple_types", ".apple_types"),
         clEnumValN(DIDT_AppleNamespaces, "apple_namespaces",
                    ".apple_namespaces"),
static bool VerifyObjectFile(ObjectFile &Obj, Twine Filename) {
   return Result;
 }
 
 static bool VerifyInput(StringRef Filename) {
   ErrorOr<std::unique_ptr<MemoryBuffer>> BuffOrErr =
   MemoryBuffer::getFileOrSTDIN(Filename);
   error(Filename, BuffOrErr.getError());
   std::unique_ptr<MemoryBuffer> Buff = std::move(BuffOrErr.get());
-  
   Expected<std::unique_ptr<Binary>> BinOrErr =
   object::createBinary(Buff->getMemBufferRef());
   if (!BinOrErr)
     error(Filename, errorToErrorCode(BinOrErr.takeError()));
-  
   bool Result = true;
   if (auto *Obj = dyn_cast<ObjectFile>(BinOrErr->get()))
     Result = VerifyObjectFile(*Obj, Filename);
   else if (auto *Fat = dyn_cast<MachOUniversalBinary>(BinOrErr->get()))
     for (auto &ObjForArch : Fat->objects()) {
       auto MachOOrErr = ObjForArch.getAsObjectFile();
       error(Filename, errorToErrorCode(MachOOrErr.takeError()));
       if (!VerifyObjectFile(**MachOOrErr, Filename + " (" + ObjForArch.getArchFlagName() + ")"))
int main(int argc, char **argv) {
   PrettyStackTraceProgram X(argc, argv);
   llvm_shutdown_obj Y;  // Call llvm_shutdown() on exit.
 
   llvm::InitializeAllTargetInfos();
   llvm::InitializeAllTargetMCs();
 
   cl::ParseCommandLineOptions(argc, argv, "llvm dwarf dumper\n");
 
+  // Defaults to dumping all sections, unless brief mode is specified in which
+  // case only the .debug_info section in dumped.
+  if (DumpType == DIDT_Null) {
+    if (Brief)
+      DumpType = DIDT_Info;
+    else
+      DumpType = DIDT_All;
+  }
+
   // Defaults to a.out if no filenames specified.
   if (InputFilenames.size() == 0)
     InputFilenames.push_back("a.out");
 
   // Expand any .dSYM bundles to the individual object files contained therein.
   std::vector<std::string> Objects;
   for (const auto &F : InputFilenames) {
     auto Objs = expandBundle(F);