Fix a backwards compatibility bug found by Tanya. In version 1.2, the

global type plane starts with a length and the TypeTyID value to identify
the type plane has having type definitions. This doesn't happen in 1.3
because the types are read from a known position in the file. However, the
TypeTyID must be read in (and ignored) if its a 1.2 bytecode file.

llvm-svn: 14728

1 files changed, 5 insertions, 0 deletions

diff --git a/llvm/lib/Bytecode/Reader/Reader.cpp b/llvm/lib/Bytecode/Reader/Reader.cpp
index 14f6c9f7e27..1b11f22e5cf 100644
--- a/llvm/lib/Bytecode/Reader/Reader.cpp
+++ b/llvm/lib/Bytecode/Reader/Reader.cpp
@@ -1641,6 +1641,11 @@ void BytecodeReader::ParseAllFunctionBodies() {
 void BytecodeReader::ParseGlobalTypes() {
   // Read the number of types
   unsigned NumEntries = read_vbr_uint();
+
+  // Ignore the type plane identifier for types if the bc file is pre 1.3
+  if (hasTypeDerivedFromValue)
+    read_vbr_uint();
+
   ParseTypeConstants(ModuleTypes, NumEntries);
 }