[DWARF parser] Teach DIContext to fetch short (non-linkage) function names for a given address.

Change --functions option in llvm-symbolizer tool to accept
values "none", "short" or "linkage". Update the tests and docs
accordingly.

llvm-svn: 209050

docs/CommandGuide/llvm-symbolizer.rst

@@ -61,11 +61,14 @@ OPTIONS
 -------
 
 .. option:: -obj
+
   Path to object file to be symbolized.
 
-.. option:: -functions
+.. option:: -functions=[none|short|linkage]
 
-  Print function names as well as source file/line locations. Defaults to true.
+  Specify the way function names are printed (omit function name,
+  print short function name, or print full linkage name, respectively).
+  Defaults to ``linkage``.
 
 .. option:: -use-symbol-table
 

include/llvm/DebugInfo/DIContext.h

@@ -70,7 +70,7 @@ class DIInliningInfo {
 /// should be filled with data.
 struct DILineInfoSpecifier {
   enum class FileLineInfoKind { None, Default, AbsoluteFilePath };
-  enum class FunctionNameKind { None, LinkageName };
+  enum class FunctionNameKind { None, ShortName, LinkageName };
 
   FileLineInfoKind FLIKind;
   FunctionNameKind FNKind;

lib/DebugInfo/DWARFDebugInfoEntry.cpp

@@ -277,13 +277,15 @@ DWARFDebugInfoEntryMinimal::getSubroutineName(const DWARFUnit *U,
                                               FunctionNameKind Kind) const {
   if (!isSubroutineDIE() || Kind == FunctionNameKind::None)
     return nullptr;
-  // Try to get mangled name if possible.
-  if (const char *name =
-      getAttributeValueAsString(U, DW_AT_MIPS_linkage_name, nullptr))
-    return name;
-  if (const char *name = getAttributeValueAsString(U, DW_AT_linkage_name,
-                                                   nullptr))
-    return name;
+  // Try to get mangled name only if it was asked for.
+  if (Kind == FunctionNameKind::LinkageName) {
+    if (const char *name =
+            getAttributeValueAsString(U, DW_AT_MIPS_linkage_name, nullptr))
+      return name;
+    if (const char *name =
+            getAttributeValueAsString(U, DW_AT_linkage_name, nullptr))
+      return name;
+  }
   if (const char *name = getAttributeValueAsString(U, DW_AT_name, nullptr))
     return name;
   // Try to get name from specification DIE.

test/DebugInfo/llvm-symbolizer.test

@@ -10,7 +10,7 @@ RUN: echo "%p/Inputs/macho-universal:i386 0x1f67" >> %t.input
 RUN: echo "%p/Inputs/macho-universal:x86_64 0x100000f05" >> %t.input
 RUN: echo "%p/Inputs/llvm-symbolizer-dwo-test 0x400514" >> %t.input
 
-RUN: llvm-symbolizer --functions --inlining --demangle=false \
+RUN: llvm-symbolizer --functions=linkage --inlining --demangle=false \
 RUN:    --default-arch=i386 < %t.input | FileCheck %s
 
 CHECK:       main
@@ -87,3 +87,9 @@ RUN: llvm-symbolizer --obj %p/Inputs/shared-object-stripped.elf-i386 < %t.input6
 RUN:   | FileCheck %s --check-prefix=STRIPPED
 
 STRIPPED:  global_func
+
+RUN: echo "%p/Inputs/dwarfdump-test4.elf-x86-64 0x62c" > %t.input7
+RUN: llvm-symbolizer --functions=short --use-symbol-table=false --demangle=false < %t.input7 \
+RUN:    | FileCheck %s --check-prefix=SHORT_FUNCTION_NAME
+
+SHORT_FUNCTION_NAME-NOT: _Z1cv

tools/llvm-symbolizer/LLVMSymbolize.cpp

@@ -39,8 +39,7 @@ static DILineInfoSpecifier
 getDILineInfoSpecifier(const LLVMSymbolizer::Options &Opts) {
   return DILineInfoSpecifier(
       DILineInfoSpecifier::FileLineInfoKind::AbsoluteFilePath,
-      Opts.PrintFunctions ? DILineInfoSpecifier::FunctionNameKind::LinkageName
-                          : DILineInfoSpecifier::FunctionNameKind::None);
+      Opts.PrintFunctions);
 }
 
 ModuleInfo::ModuleInfo(ObjectFile *Obj, DIContext *DICtx)
@@ -117,7 +116,7 @@ DILineInfo ModuleInfo::symbolizeCode(
         ModuleOffset, getDILineInfoSpecifier(Opts));
   }
   // Override function name from symbol table if necessary.
-  if (Opts.PrintFunctions && Opts.UseSymbolTable) {
+  if (Opts.PrintFunctions != FunctionNameKind::None && Opts.UseSymbolTable) {
     std::string FunctionName;
     uint64_t Start, Size;
     if (getNameFromSymbolTable(SymbolRef::ST_Function, ModuleOffset,
@@ -140,7 +139,7 @@ DIInliningInfo ModuleInfo::symbolizeInlinedCode(
     InlinedContext.addFrame(DILineInfo());
   }
   // Override the function name in lower frame with name from symbol table.
-  if (Opts.PrintFunctions && Opts.UseSymbolTable) {
+  if (Opts.PrintFunctions != FunctionNameKind::None && Opts.UseSymbolTable) {
     DIInliningInfo PatchedInlinedContext;
     for (uint32_t i = 0, n = InlinedContext.getNumberOfFrames(); i < n; i++) {
       DILineInfo LineInfo = InlinedContext.getFrame(i);
@@ -398,7 +397,7 @@ std::string LLVMSymbolizer::printDILineInfo(DILineInfo LineInfo) const {
   // cannot fetch. We replace it to "??" to make our output closer to addr2line.
   static const std::string kDILineInfoBadString = "<invalid>";
   std::stringstream Result;
-  if (Opts.PrintFunctions) {
+  if (Opts.PrintFunctions != FunctionNameKind::None) {
     std::string FunctionName = LineInfo.FunctionName;
     if (FunctionName == kDILineInfoBadString)
       FunctionName = kBadString;

tools/llvm-symbolizer/LLVMSymbolize.h

@@ -24,6 +24,7 @@
 
 namespace llvm {
 
+typedef DILineInfoSpecifier::FunctionNameKind FunctionNameKind;
 using namespace object;
 
 namespace symbolize {
@@ -34,17 +35,17 @@ class LLVMSymbolizer {
 public:
   struct Options {
     bool UseSymbolTable : 1;
-    bool PrintFunctions : 1;
+    FunctionNameKind PrintFunctions;
     bool PrintInlining : 1;
     bool Demangle : 1;
     std::string DefaultArch;
-    Options(bool UseSymbolTable = true, bool PrintFunctions = true,
+    Options(bool UseSymbolTable = true,
+            FunctionNameKind PrintFunctions = FunctionNameKind::LinkageName,
             bool PrintInlining = true, bool Demangle = true,
             std::string DefaultArch = "")
         : UseSymbolTable(UseSymbolTable), PrintFunctions(PrintFunctions),
           PrintInlining(PrintInlining), Demangle(Demangle),
-          DefaultArch(DefaultArch) {
-    }
+          DefaultArch(DefaultArch) {}
   };
 
   LLVMSymbolizer(const Options &Opts = Options()) : Opts(Opts) {}

tools/llvm-symbolizer/llvm-symbolizer.cpp

@@ -35,10 +35,15 @@ ClUseSymbolTable("use-symbol-table", cl::init(true),
                  cl::desc("Prefer names in symbol table to names "
                           "in debug info"));
 
-static cl::opt<bool>
-ClPrintFunctions("functions", cl::init(true),
-                 cl::desc("Print function names as well as line "
-                          "information for a given address"));
+static cl::opt<FunctionNameKind> ClPrintFunctions(
+    "functions", cl::init(FunctionNameKind::LinkageName),
+    cl::desc("Print function name for a given address:"),
+    cl::values(clEnumValN(FunctionNameKind::None, "none", "omit function name"),
+               clEnumValN(FunctionNameKind::ShortName, "short",
+                          "print short function name"),
+               clEnumValN(FunctionNameKind::LinkageName, "linkage",
+                          "print function linkage name"),
+               clEnumValEnd));
 
 static cl::opt<bool>
 ClPrintInlining("inlining", cl::init(true),