[PATCH] D66130: [ELF] Initialize 2 fields of Symbol in SymbolTable::insert

[Fangrui Song via Phabricator via llvm-commits]

MaskRay created this revision.
MaskRay added reviewers: grimar, peter.smith, ruiu.
Herald added subscribers: llvm-commits, arichardson, emaste.
Herald added a reviewer: espindola.
Herald added a project: LLVM.

A new symbol is added to elf::symtab in 3 steps:

1. SymbolTable::insert creates a placeholder.
2. Symbol::mergeProperties
3. Symbol::replace

Fields referenced by steps 2) and 3) should be initialized in
SymbolTable::insert.  `traced` and `referenced` were missed previously.
This did not cause problems because compilers generated code that
initialized them (bit fields) to 0.


Repository:
  rLLD LLVM Linker

https://reviews.llvm.org/D66130

Files:
  ELF/SymbolTable.cpp
  ELF/Symbols.h


Index: ELF/Symbols.h
===================================================================
--- ELF/Symbols.h
+++ ELF/Symbols.h
@@ -537,6 +537,8 @@
   Symbol old = *this;
   memcpy(this, &newSym, newSym.getSymbolSize());
 
+  // Old fields that are referenced here must be initialized in
+  // SymbolTable::insert.
   versionId = old.versionId;
   visibility = old.visibility;
   isUsedInRegularObj = old.isUsedInRegularObj;
Index: ELF/SymbolTable.cpp
===================================================================
--- ELF/SymbolTable.cpp
+++ ELF/SymbolTable.cpp
@@ -71,6 +71,8 @@
   Symbol *sym = reinterpret_cast<Symbol *>(make<SymbolUnion>());
   symVector.push_back(sym);
 
+  // Fields referenced by Symbol::mergeProperties and Symbol::replace must be
+  // initialized here.
   sym->setName(name);
   sym->symbolKind = Symbol::PlaceholderKind;
   sym->versionId = VER_NDX_GLOBAL;
@@ -79,6 +81,8 @@
   sym->exportDynamic = false;
   sym->inDynamicList = false;
   sym->canInline = true;
+  sym->referenced = false;
+  sym->traced = false;
   sym->scriptDefined = false;
   sym->partition = 1;
   return sym;


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