[PATCH] D58952: [llvm] Skip over empty line table entries.

[Mircea Trofin via Phabricator via llvm-commits]

mtrofin created this revision.
Herald added subscribers: llvm-commits, jdoerfert, rupprecht, hiraditya.
Herald added a project: LLVM.
mtrofin added a reviewer: dblaikie.

This is similar to how addr2line handles consecutive entries with the
same address - pick the last one.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D58952

Files:
  llvm/lib/DebugInfo/DWARF/DWARFDebugLine.cpp
  llvm/test/tools/llvm-symbolizer/fission-ranges.test
  llvm/test/tools/llvm-symbolizer/sym-verbose.test


Index: llvm/test/tools/llvm-symbolizer/sym-verbose.test
===================================================================
--- llvm/test/tools/llvm-symbolizer/sym-verbose.test
+++ llvm/test/tools/llvm-symbolizer/sym-verbose.test
@@ -19,8 +19,8 @@
 #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: Line: 5
+#CHECK-NEXT: Column: 7
 #CHECK-NEXT: main
 #CHECK-NEXT: Filename: /tmp{{[\\/]}}discrim.c
 #CHECK-NEXT: Function start line: 9
Index: llvm/test/tools/llvm-symbolizer/fission-ranges.test
===================================================================
--- llvm/test/tools/llvm-symbolizer/fission-ranges.test
+++ llvm/test/tools/llvm-symbolizer/fission-ranges.test
@@ -1,4 +1,4 @@
 RUN: llvm-symbolizer --obj=%p/Inputs/fission-ranges.elf-x86_64 0x720 | FileCheck %s
 
 CHECK: main
-CHECK-NEXT: {{.*}}fission-ranges.cc:6
+CHECK-NEXT: {{.*}}fission-ranges.cc:2
Index: llvm/lib/DebugInfo/DWARF/DWARFDebugLine.cpp
===================================================================
--- llvm/lib/DebugInfo/DWARF/DWARFDebugLine.cpp
+++ llvm/lib/DebugInfo/DWARF/DWARFDebugLine.cpp
@@ -867,8 +867,11 @@
   Row.Address = Address;
   RowIter FirstRow = Rows.begin() + Seq.FirstRowIndex;
   RowIter LastRow = Rows.begin() + Seq.LastRowIndex;
-  LineTable::RowIter RowPos = std::lower_bound(
+  // In some cases, e.g. first instruction in a function, the compiler generates
+  // two entries, both with the same address. We want the last one.
+  LineTable::RowIter RowPos = std::upper_bound(
       FirstRow, LastRow, Row, DWARFDebugLine::Row::orderByAddress);
+  --RowPos;
   if (RowPos == LastRow) {
     return Seq.LastRowIndex - 1;
   }


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