[PATCH] D93306: [llvm-symbolizer][Windows] Add start line when searching in line table sections.

[Amy Huang via Phabricator via llvm-commits]

akhuang created this revision.
akhuang added reviewers: rnk, amccarth.
Herald added subscribers: rupprecht, hiraditya.
Herald added a reviewer: jhenderson.
akhuang requested review of this revision.
Herald added subscribers: llvm-commits, MaskRay.
Herald added a project: LLVM.

Fixes issue where if a line section doesn't start with a line number
then the addresses at the beginning of the section don't have line numbers.

For example, for a line section like this

  0001:00000010-00000014, line/column/addr entries = 1
     7 00000013 !

a line number wouldn't be found for addresses from 10 to 12.

This matches behavior when using the DIA SDK.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D93306

Files:
  llvm/lib/DebugInfo/PDB/Native/SymbolCache.cpp
  llvm/test/tools/llvm-symbolizer/pdb/Inputs/test-line-numbers.cpp
  llvm/test/tools/llvm-symbolizer/pdb/Inputs/test-line-numbers.exe
  llvm/test/tools/llvm-symbolizer/pdb/pdb-line-numbers.test


Index: llvm/test/tools/llvm-symbolizer/pdb/pdb-line-numbers.test
===================================================================
--- /dev/null
+++ llvm/test/tools/llvm-symbolizer/pdb/pdb-line-numbers.test
@@ -0,0 +1,16 @@
+RUN: llvm-symbolizer --obj="%p/Inputs/test-line-numbers.exe" \
+RUN:   --relative-address 0x1000 0x1003 0x1010 0x1013 | FileCheck %s
+
+CHECK:      f1(int)
+CHECK-NEXT: t.cpp:2:13
+
+CHECK:      f1(int)
+CHECK-NEXT: t.cpp:3:3
+
+CHECK:      f1
+CHECK-NEXT: t.cpp:2:0
+CHECK-NEXT: f2(int)
+CHECK-NEXT: t.cpp:7:3
+
+CHECK:      f2(int)
+CHECK:      t.cpp:7:3
Index: llvm/test/tools/llvm-symbolizer/pdb/Inputs/test-line-numbers.cpp
===================================================================
--- /dev/null
+++ llvm/test/tools/llvm-symbolizer/pdb/Inputs/test-line-numbers.cpp
@@ -0,0 +1,16 @@
+// To generate the corresponding EXE/PDB, run:
+// clang -cc1 -triple x86_64-windows-msvc -gcodeview -debug-info-kind=limited -O2 -emit-obj t.cpp
+// lld-link -entry:main -debug t.obj
+
+int f1(int x) {
+  int y = x + 1;
+  return y;
+}
+
+int f2(int n) {
+  return f1(n);
+}
+
+int main() {
+  return f2(100);
+}
Index: llvm/lib/DebugInfo/PDB/Native/SymbolCache.cpp
===================================================================
--- llvm/lib/DebugInfo/PDB/Native/SymbolCache.cpp
+++ llvm/lib/DebugInfo/PDB/Native/SymbolCache.cpp
@@ -481,11 +481,19 @@
       auto ColIt = Group.Columns.begin();
       auto ColsEnd = Group.Columns.end();
 
+      // Add a line to mark the beginning of this section.
+      uint64_t StartAddr =
+          Session.getVAFromSectOffset(RelocSegment, RelocOffset);
+      LineInfo FirstLine(Group.LineNumbers.front().Flags);
+      uint32_t ColNum =
+          (Lines.hasColumnInfo()) ? Group.Columns.front().StartColumn : 0;
+      Entries.push_back({StartAddr, FirstLine, ColNum, Group.NameIndex, false});
+
       for (const LineNumberEntry &LN : Group.LineNumbers) {
         uint64_t VA =
             Session.getVAFromSectOffset(RelocSegment, RelocOffset + LN.Offset);
         LineInfo Line(LN.Flags);
-        uint32_t ColNum = 0;
+        ColNum = 0;
 
         if (Lines.hasColumnInfo() && ColIt != ColsEnd) {
           ColNum = ColIt->StartColumn;
@@ -495,12 +503,10 @@
       }
 
       // Add a terminal entry line to mark the end of this subsection.
-      uint64_t VA = Session.getVAFromSectOffset(
-          RelocSegment, RelocOffset + Lines.header()->CodeSize);
+      uint64_t EndAddr = StartAddr + Lines.header()->CodeSize;
       LineInfo LastLine(Group.LineNumbers.back().Flags);
-      uint32_t ColNum =
-          (Lines.hasColumnInfo()) ? Group.Columns.back().StartColumn : 0;
-      Entries.push_back({VA, LastLine, ColNum, Group.NameIndex, true});
+      ColNum = (Lines.hasColumnInfo()) ? Group.Columns.back().StartColumn : 0;
+      Entries.push_back({EndAddr, LastLine, ColNum, Group.NameIndex, true});
 
       EntryList.push_back(Entries);
     }


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