[llvm] b7acb3d - [DebugInfo] Force users of DWARFDebugAbbrev to call parse before iterating

[Alex Langford via llvm-commits]

Author: Alex Langford
Date: 2023-07-13T11:31:18-07:00
New Revision: b7acb3d4a5d769f014ce850efa197862616c2baa

URL: https://github.com/llvm/llvm-project/commit/b7acb3d4a5d769f014ce850efa197862616c2baa
DIFF: https://github.com/llvm/llvm-project/commit/b7acb3d4a5d769f014ce850efa197862616c2baa.diff

LOG: [DebugInfo] Force users of DWARFDebugAbbrev to call parse before iterating

In an attempt to make it easier to catch errors when parsing the
debug_abbrev section, we should force users to call `parse` before
calling `begin`. In a follow-up change, I will change the return type of
`parse` from `void` to `Error`.

I also explored using the fallible_iterator pattern instead of forcing
users to parse everything up front. I think it would be a useful and
interesting pattern to implement, but it would require more extensive
changes to both DWARFDebugAbbrev and its users. Because my top priority
is improving the safety around parsing debug_abbrev, I'm opting to
preserve existing behavior until I or somebody else has time to refactor
to be able to implement a fallible_iterator.

Differential Revision: https://reviews.llvm.org/D154655

Added: 
    

Modified: 
    llvm/include/llvm/DebugInfo/DWARF/DWARFDebugAbbrev.h
    llvm/tools/obj2yaml/dwarf2yaml.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/include/llvm/DebugInfo/DWARF/DWARFDebugAbbrev.h b/llvm/include/llvm/DebugInfo/DWARF/DWARFDebugAbbrev.h
index 5f1bf26c36d817..8e4aa3aa61e9ea 100644
--- a/llvm/include/llvm/DebugInfo/DWARF/DWARFDebugAbbrev.h
+++ b/llvm/include/llvm/DebugInfo/DWARF/DWARFDebugAbbrev.h
@@ -73,7 +73,7 @@ class DWARFDebugAbbrev {
   void parse() const;
 
   DWARFAbbreviationDeclarationSetMap::const_iterator begin() const {
-    parse();
+    assert(!Data && "Must call parse before iterating over DWARFDebugAbbrev");
     return AbbrDeclSets.begin();
   }
 

diff  --git a/llvm/tools/obj2yaml/dwarf2yaml.cpp b/llvm/tools/obj2yaml/dwarf2yaml.cpp
index 4c4ae3f713486a..3d3798d5f18d78 100644
--- a/llvm/tools/obj2yaml/dwarf2yaml.cpp
+++ b/llvm/tools/obj2yaml/dwarf2yaml.cpp
@@ -26,6 +26,7 @@ void dumpDebugAbbrev(DWARFContext &DCtx, DWARFYAML::Data &Y) {
   auto AbbrevSetPtr = DCtx.getDebugAbbrev();
   if (AbbrevSetPtr) {
     uint64_t AbbrevTableID = 0;
+    AbbrevSetPtr->parse();
     for (auto AbbrvDeclSet : *AbbrevSetPtr) {
       Y.DebugAbbrev.emplace_back();
       Y.DebugAbbrev.back().ID = AbbrevTableID++;
@@ -219,6 +220,7 @@ void dumpDebugInfo(DWARFContext &DCtx, DWARFYAML::Data &Y) {
     if (NewUnit.Version >= 5)
       NewUnit.Type = (dwarf::UnitType)CU->getUnitType();
     const DWARFDebugAbbrev *DebugAbbrev = DCtx.getDebugAbbrev();
+    DebugAbbrev->parse();
     NewUnit.AbbrevTableID = std::distance(
         DebugAbbrev->begin(),
         llvm::find_if(