[PATCH] D19522: Read discriminators correctly from object file.

[Dehao Chen via llvm-commits]

danielcdh created this revision.
danielcdh added reviewers: dblaikie, dnovillo, echristo.
danielcdh added a subscriber: llvm-commits.
Herald added a subscriber: joker.eph.

This is the follow-up patch for http://reviews.llvm.org/D19436
* Update the discriminator reading algorithm to match the assignment algorithm.
* Add test to cover the new algorithm.

http://reviews.llvm.org/D19522

Files:
  lib/DebugInfo/DWARF/DWARFDebugLine.cpp
  test/DebugInfo/X86/discriminator2.ll

Index: test/DebugInfo/X86/discriminator2.ll
===================================================================
--- /dev/null
+++ test/DebugInfo/X86/discriminator2.ll
@@ -0,0 +1,43 @@
+; RUN: llc -mtriple=i386-unknown-unknown -mcpu=core2 %s -o %t -filetype=obj
+; RUN: llvm-dwarfdump -debug-dump=line %t | FileCheck %s
+
+; Function Attrs: uwtable
+define void @_Z3bazv() #0 !dbg !6 {
+  %1 = call i32 @_Z3barv(), !dbg !9
+  %2 = call i32 @_Z3barv(), !dbg !10
+  call void @_Z3fooii(i32 %1, i32 %2), !dbg !11
+  %3 = call i32 @_Z3barv(), !dbg !13
+  ret void, !dbg !14
+}
+
+declare void @_Z3fooii(i32, i32) #1
+
+declare i32 @_Z3barv() #1
+
+attributes #0 = { uwtable "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+fxsr,+mmx,+sse,+sse2,+x87" "unsafe-fp-math"="false" "use-soft-float"="false" }
+attributes #1 = { "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+fxsr,+mmx,+sse,+sse2,+x87" "unsafe-fp-math"="false" "use-soft-float"="false" }
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!3, !4}
+!llvm.ident = !{!5}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "clang version 3.9.0 (trunk 267219)", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2)
+!1 = !DIFile(filename: "test.cc", directory: ".")
+!2 = !{}
+!3 = !{i32 2, !"Dwarf Version", i32 4}
+!4 = !{i32 2, !"Debug Info Version", i32 3}
+!5 = !{!"clang version 3.9.0 (trunk 267219)"}
+!6 = distinct !DISubprogram(name: "baz", linkageName: "_Z3bazv", scope: !1, file: !1, line: 3, type: !7, isLocal: false, isDefinition: true, scopeLine: 3, flags: DIFlagPrototyped, isOptimized: false, unit: !0, variables: !2)
+!7 = !DISubroutineType(types: !8)
+!8 = !{null}
+!9 = !DILocation(line: 4, column: 7, scope: !6)
+!10 = !DILocation(line: 5, column: 14, scope: !6)
+!11 = !DILocation(line: 4, column: 3, scope: !12)
+!12 = !DILexicalBlockFile(scope: !6, file: !1, discriminator: 1)
+!13 = !DILocation(line: 5, column: 21, scope: !12)
+!14 = !DILocation(line: 6, column: 1, scope: !6)
+
+; CHECK: Address            Line   Column File   ISA Discriminator Flags
+; CHECK: ------------------ ------ ------ ------ --- ------------- -------------
+; CHECK: {{.*}}      4      3      1   0             1  {{.*}}
+; CHECK: {{.*}}      5     21      1   0             1  {{.*}}
Index: lib/DebugInfo/DWARF/DWARFDebugLine.cpp
===================================================================
--- lib/DebugInfo/DWARF/DWARFDebugLine.cpp
+++ lib/DebugInfo/DWARF/DWARFDebugLine.cpp
@@ -375,10 +375,15 @@
         break;
 
       case DW_LNS_advance_line:
-        // Takes a single signed LEB128 operand and adds that value to
-        // the line register of the state machine.
-        State.Row.Line += debug_line_data.getSLEB128(offset_ptr);
-        break;
+        {
+          // Takes a single signed LEB128 operand and adds that value to
+          // the line register of the state machine.
+          int32_t line_offset = debug_line_data.getSLEB128(offset_ptr);
+          State.Row.Line += line_offset;
+          if (line_offset != 0)
+            State.Row.Discriminator = 0;
+          break;
+        }
 
       case DW_LNS_set_file:
         // Takes a single unsigned LEB128 operand and stores it in the file
@@ -509,6 +514,8 @@
       State.Row.Line += line_offset;
       State.Row.Address += addr_offset;
       State.appendRowToMatrix(*offset_ptr);
+      if (line_offset != 0)
+        State.Row.Discriminator = 0;
     }
   }
 


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