[PATCH] D40156: Fix recursive attribute fetching in DWARFDie

[Greg Clayton via Phabricator via llvm-commits]

clayborg created this revision.
Herald added a subscriber: JDevlieghere.

The previous implementation would only look 1 DW_AT_specification or DW_AT_abstract_origin deep. This means DWARFDie::getName() would fail in certain cases. I ran into such a case while creating a tool that used the LLVM DWARF parser to generate a symbolication format so I have seen this in the wild.


Repository:
  rL LLVM

https://reviews.llvm.org/D40156

Files:
  lib/DebugInfo/DWARF/DWARFDie.cpp
  unittests/DebugInfo/DWARF/DWARFDebugInfoTest.cpp


Index: unittests/DebugInfo/DWARF/DWARFDebugInfoTest.cpp
===================================================================
--- unittests/DebugInfo/DWARF/DWARFDebugInfoTest.cpp
+++ unittests/DebugInfo/DWARF/DWARFDebugInfoTest.cpp
@@ -1287,12 +1287,16 @@
     auto CUDie = CU.getUnitDIE();
     auto FuncSpecDie = CUDie.addChild(DW_TAG_subprogram);
     auto FuncAbsDie = CUDie.addChild(DW_TAG_subprogram);
+    // Put the linkage name in a second abstract origin DIE to ensure we
+    // recurse through more than just one DIE when looking for attributes.
+    auto FuncAbsDie2 = CUDie.addChild(DW_TAG_subprogram);
     auto FuncDie = CUDie.addChild(DW_TAG_subprogram);
     auto VarAbsDie = CUDie.addChild(DW_TAG_variable);
     auto VarDie = CUDie.addChild(DW_TAG_variable);
     FuncSpecDie.addAttribute(DW_AT_name, DW_FORM_strp, SpecDieName);
-    FuncAbsDie.addAttribute(DW_AT_linkage_name, DW_FORM_strp, SpecLinkageName);
+    FuncAbsDie2.addAttribute(DW_AT_linkage_name, DW_FORM_strp, SpecLinkageName);
     FuncAbsDie.addAttribute(DW_AT_specification, DW_FORM_ref4, FuncSpecDie);
+    FuncAbsDie.addAttribute(DW_AT_abstract_origin, DW_FORM_ref4, FuncAbsDie2);
     FuncDie.addAttribute(DW_AT_abstract_origin, DW_FORM_ref4, FuncAbsDie);
     VarAbsDie.addAttribute(DW_AT_name, DW_FORM_strp, AbsDieName);
     VarDie.addAttribute(DW_AT_abstract_origin, DW_FORM_ref4, VarAbsDie);
@@ -1314,7 +1318,8 @@
 
   auto FuncSpecDie = CUDie.getFirstChild();
   auto FuncAbsDie = FuncSpecDie.getSibling();
-  auto FuncDie = FuncAbsDie.getSibling();
+  auto FuncAbsDie2 = FuncAbsDie.getSibling();
+  auto FuncDie = FuncAbsDie2.getSibling();
   auto VarAbsDie = FuncDie.getSibling();
   auto VarDie = VarAbsDie.getSibling();
 
Index: lib/DebugInfo/DWARF/DWARFDie.cpp
===================================================================
--- lib/DebugInfo/DWARF/DWARFDie.cpp
+++ lib/DebugInfo/DWARF/DWARFDie.cpp
@@ -298,17 +298,16 @@
 DWARFDie::findRecursively(ArrayRef<dwarf::Attribute> Attrs) const {
   if (!isValid())
     return None;
-  auto Die = *this;
-  if (auto Value = Die.find(Attrs))
+  if (auto Value = find(Attrs))
     return Value;
-  if (auto D = Die.getAttributeValueAsReferencedDie(DW_AT_abstract_origin))
-    Die = D;
-  if (auto Value = Die.find(Attrs))
-    return Value;
-  if (auto D = Die.getAttributeValueAsReferencedDie(DW_AT_specification))
-    Die = D;
-  if (auto Value = Die.find(Attrs))
-    return Value;
+  if (auto Die = getAttributeValueAsReferencedDie(DW_AT_abstract_origin)) {
+    if (auto Value = Die.findRecursively(Attrs))
+      return Value;
+  }
+  if (auto Die = getAttributeValueAsReferencedDie(DW_AT_specification)) {
+    if (auto Value = Die.findRecursively(Attrs))
+      return Value;
+  }
   return None;
 }
 


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