[PATCH] D59051: Fix ASTReader invalid bounds check

[Christy Lee via Phabricator via llvm-commits]

christylee created this revision.
Herald added a project: LLVM.
Herald added a subscriber: llvm-commits.
christylee added reviewers: tks2103, modocache.

The ASTReader does the index bounds check before incrementing the index, so `Clang :: Modules/module_file_info.m` failed on `include/llvm/ADT/SmallVector.h:153 assert(idx < size())`.  This fixes the bounds check by incrementing first.


Repository:
  rL LLVM

https://reviews.llvm.org/D59051

Files:
  clang/lib/Serialization/ASTReader.cpp


Index: clang/lib/Serialization/ASTReader.cpp
===================================================================
--- clang/lib/Serialization/ASTReader.cpp
+++ clang/lib/Serialization/ASTReader.cpp
@@ -4863,10 +4863,11 @@
       if (!NeedsImports)
         break;
 
-      unsigned Idx = 0, N = Record.size();
-      while (Idx < N) {
+      // Kind, ImportLoc, Size, ModTime, Signature
+      unsigned chunkSize = 1+1+1+1+5;
+      unsigned N = Record.size();
+      for (unsigned Idx = chunkSize; Idx < N; Idx += chunkSize) {
         // Read information about the AST file.
-        Idx += 1+1+1+1+5; // Kind, ImportLoc, Size, ModTime, Signature
         std::string ModuleName = ReadString(Record, Idx);
         std::string Filename = ReadString(Record, Idx);
         ResolveImportedPath(Filename, ModuleDir);


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