Add GNU_discriminator support for inline callsites in llvm-symbolizer.

[danielcdh]

Summary

LLVM symbolize cannot recognize GNU_discriminator for inline callsites. This patch adds support for it.

[dblaikie]

Oops, forgot to type a message so the approval wouldn't've been sent to the mailing list:

Approved, looks good! :)

include/llvm/DebugInfo/DWARF/DWARFDie.h

public:
   /// DW_AT_call attributes in this DIE only, it will not resolve the attribute
   /// values in any DW_AT_specification or DW_AT_abstract_origin DIEs.
   /// \param CallFile filled in with non-zero if successful, zero if there is no
   /// DW_AT_call_file attribute in this DIE.
   /// \param CallLine filled in with non-zero if successful, zero if there is no
   /// DW_AT_call_line attribute in this DIE.
   /// \param CallColumn filled in with non-zero if successful, zero if there is
   /// no DW_AT_call_column attribute in this DIE.
+  /// \param CallDiscriminator filled in with non-zero if successful, zero if
+  /// there is no DW_AT_GNU_discriminator attribute in this DIE.
   void getCallerFrame(uint32_t &CallFile, uint32_t &CallLine,
-                      uint32_t &CallColumn) const;
+                      uint32_t &CallColumn, uint32_t &CallDiscriminator) const;
   
   /// Get inlined chain for a given address, rooted at the current DIE.
   /// Returns empty chain if address is not contained in address range
   /// of current DIE.
   void
   getInlinedChainForAddress(const uint64_t Address,
                             SmallVectorImpl<DWARFDie> &InlinedChain) const;
 

lib/DebugInfo/DWARF/DWARFContext.cpp

if (Spec.FLIKind != FileLineInfoKind::None) {
       if (LineTable &&
           LineTable->getFileLineInfoForAddress(Address, CU->getCompilationDir(),
                                                Spec.FLIKind, Frame))
         InliningInfo.addFrame(Frame);
     }
     return InliningInfo;
   }
 
-  uint32_t CallFile = 0, CallLine = 0, CallColumn = 0;
+  uint32_t CallFile = 0, CallLine = 0, CallColumn = 0, CallDiscriminator = 0;
   for (uint32_t i = 0, n = InlinedChain.size(); i != n; i++) {
     DWARFDie &FunctionDIE = InlinedChain[i];
     DILineInfo Frame;
     // Get function name if necessary.
     if (const char *Name = FunctionDIE.getSubroutineName(Spec.FNKind))
       Frame.FunctionName = Name;
     if (auto DeclLineResult = FunctionDIE.getDeclLine())
       Frame.StartLine = DeclLineResult;
if (Spec.FLIKind != FileLineInfoKind::None) {
       } else {
         // Otherwise, use call file, call line and call column from
         // previous DIE in inlined chain.
         if (LineTable)
           LineTable->getFileNameByIndex(CallFile, CU->getCompilationDir(),
                                         Spec.FLIKind, Frame.FileName);
         Frame.Line = CallLine;
         Frame.Column = CallColumn;
+        Frame.Discriminator = CallDiscriminator;
       }
       // Get call file/line/column of a current DIE.
       if (i + 1 < n) {
-        FunctionDIE.getCallerFrame(CallFile, CallLine, CallColumn);
+        FunctionDIE.getCallerFrame(CallFile, CallLine, CallColumn,
+                                   CallDiscriminator);
       }
     }
     InliningInfo.addFrame(Frame);
   }
   return InliningInfo;
 }
 
 static Error createError(const Twine &Reason, llvm::Error E) {

lib/DebugInfo/DWARF/DWARFDie.cpp

DWARFDie::getName(DINameKind Kind) const {
   return nullptr;
 }
 
 uint64_t DWARFDie::getDeclLine() const {
   return toUnsigned(findRecursively(DW_AT_decl_line), 0);
 }
 
 void DWARFDie::getCallerFrame(uint32_t &CallFile, uint32_t &CallLine,
-                              uint32_t &CallColumn) const {
+                              uint32_t &CallColumn,
+                              uint32_t &CallDiscriminator) const {
   CallFile = toUnsigned(find(DW_AT_call_file), 0);
   CallLine = toUnsigned(find(DW_AT_call_line), 0);
   CallColumn = toUnsigned(find(DW_AT_call_column), 0);
+  CallDiscriminator = toUnsigned(find(DW_AT_GNU_discriminator), 0);
 }
 
 void DWARFDie::dump(raw_ostream &OS, unsigned RecurseDepth,
                     unsigned Indent) const {
   if (!isValid())
     return;
   DataExtractor debug_info_data = U->getDebugInfoExtractor();
   const uint32_t Offset = getOffset();

test/tools/llvm-symbolizer/Inputs/discrim.c

 static volatile int do_mul;
-static volatile int do_inc;
+static volatile int x, v;
+
+int foo () {
+  if (do_mul) x *= v; else x /= v;
+  return x;
+}
 
-int main () {
-  int x = 1;
-  if (do_mul) x *= 2; else x /= 2;
-  return do_inc ? ++x : --x;
+int main() {
+  return foo() + foo();
 }

test/tools/llvm-symbolizer/Inputs/discrim.inp

 some text
-0x4004f2
-0x400509
-0x40050d
+0x400590
+0x4005a5
+0x4005ad
+0x4005b9
+0x4005ce
+0x4005d4
 some more text

test/tools/llvm-symbolizer/sym-verbose.test

 #static volatile int do_mul;
-#static volatile int do_inc;
+#static volatile int x, v;
+#
+#int foo () {
+#  if (do_mul) x *= v; else x /= v;
+#  return x;
+#}
 #
-#int main () {
-#  int x = 1;
-#  if (do_mul) x *= 2; else x /= 2;
-#  return do_inc ? ++x : --x;
+#int main() {
+#  return foo() + foo();
 #}
-#Build as : clang -g -O2 discrim.c -o discrim
+#Build as : clang -gmlt -fdebug-info-for-profiling -O2 discrim.c -o discrim
 
 RUN: llvm-symbolizer -verbose -print-address -obj=%p/Inputs/discrim < %p/Inputs/discrim.inp | FileCheck %s
 
 #CHECK: some text
 
-#CHECK: 0x4004f2
+#CHECK: 0x400590
+#CHECK-NEXT: foo
+#CHECK-NEXT: Filename: /tmp/discrim.c
+#CHECK-NEXT: Function start line: 4
+#CHECK-NEXT: Line: 9
+#CHECK-NEXT: Column: 0
 #CHECK-NEXT: main
-#CHECK-NEXT: Filename: /tmp{{[\\/]}}discrim.c
+#CHECK-NEXT: Filename: /tmp/discrim.c
+#CHECK-NEXT: Function start line: 9
+#CHECK-NEXT: Line: 10
+#CHECK-NEXT: Column: 0
+
+#CHECK: 0x4005a5
+#CHECK-NEXT: foo
+#CHECK-NEXT: Filename: /tmp/discrim.c
 #CHECK-NEXT: Function start line: 4
-#CHECK-NEXT: Line: 6
-#CHECK-NEXT: Column: 7
-#CHECK-NOT: Discriminator: 0
-
-#CHECK: 0x400509
+#CHECK-NEXT: Line: 5
+#CHECK-NEXT: Column: 17
+#CHECK-NEXT: Discriminator: 2
+#CHECK-NEXT: main
+#CHECK-NEXT: Filename: /tmp/discrim.c
+#CHECK-NEXT: Function start line: 9
+#CHECK-NEXT: Line: 10
+#CHECK-NEXT: Column: 0
+
+#CHECK: 0x4005ad
+#CHECK-NEXT: foo
+#CHECK-NEXT: Filename: /tmp/discrim.c
+#CHECK-NEXT: Function start line: 4
+#CHECK-NEXT: Line: 0
+#CHECK-NEXT: Column: 30
+#CHECK-NEXT: Discriminator: 4
 #CHECK-NEXT: main
-#CHECK-NEXT: Filename: /tmp{{[\\/]}}discrim.c
+#CHECK-NEXT: Filename: /tmp/discrim.c
+#CHECK-NEXT: Function start line: 9
+#CHECK-NEXT: Line: 10
+#CHECK-NEXT: Column: 0
+
+#CHECK: 0x4005b9
+#CHECK-NEXT: foo
+#CHECK-NEXT: Filename: /tmp/discrim.c
 #CHECK-NEXT: Function start line: 4
-#CHECK-NEXT: Line: 7
-#CHECK-NEXT: Column: 3
-#CHECK-NEXT: Discriminator: 1
+#CHECK-NEXT: Line: 5
+#CHECK-NEXT: Column: 7
+#CHECK-NEXT: main
+#CHECK-NEXT: Filename: /tmp/discrim.c
+#CHECK-NEXT: Function start line: 9
+#CHECK-NEXT: Line: 10
+#CHECK-NEXT: Column: 0
+#CHECK-NEXT: Discriminator: 2
 
-#CHECK: 0x40050d
+#CHECK: 0x4005ce
+#CHECK-NEXT: foo
+#CHECK-NEXT: Filename: /tmp/discrim.c
+#CHECK-NEXT: Function start line: 4
+#CHECK-NEXT: Line: 5
+#CHECK-NEXT: Column: 17
+#CHECK-NEXT: Discriminator: 2
 #CHECK-NEXT: main
-#CHECK-NEXT: Filename: /tmp{{[\\/]}}discrim.c
+#CHECK-NEXT: Filename: /tmp/discrim.c
+#CHECK-NEXT: Function start line: 9
+#CHECK-NEXT: Line: 10
+#CHECK-NEXT: Column: 0
+#CHECK-NEXT: Discriminator: 2
+
+#CHECK: 0x4005d4
+#CHECK-NEXT: foo
+#CHECK-NEXT: Filename: /tmp/discrim.c
 #CHECK-NEXT: Function start line: 4
-#CHECK-NEXT: Line: 7
-#CHECK-NEXT: Column: 3
+#CHECK-NEXT: Line: 5
+#CHECK-NEXT: Column: 30
+#CHECK-NEXT: Discriminator: 4
+#CHECK-NEXT: main
+#CHECK-NEXT: Filename: /tmp/discrim.c
+#CHECK-NEXT: Function start line: 9
+#CHECK-NEXT: Line: 10
+#CHECK-NEXT: Column: 0
 #CHECK-NEXT: Discriminator: 2
 
 #CHECK: some more text