Be more careful in parsing Module::ModFlagBehavior value
to make sure we don't do invalid load of an enum. Share the
conversion code between llvm::Module implementation and the
verifier.
This bug was reported by UBSan.
llvm-svn: 217395
diff --git a/llvm/lib/IR/Verifier.cpp b/llvm/lib/IR/Verifier.cpp
index 0df257d..1a182db 100644
--- a/llvm/lib/IR/Verifier.cpp
+++ b/llvm/lib/IR/Verifier.cpp
@@ -673,24 +673,23 @@
// constant int), the flag ID (an MDString), and the value.
Assert1(Op->getNumOperands() == 3,
"incorrect number of operands in module flag", Op);
- ConstantInt *Behavior = dyn_cast<ConstantInt>(Op->getOperand(0));
+ Module::ModFlagBehavior MFB;
+ if (!Module::isValidModFlagBehavior(Op->getOperand(0), MFB)) {
+ Assert1(
+ dyn_cast<ConstantInt>(Op->getOperand(0)),
+ "invalid behavior operand in module flag (expected constant integer)",
+ Op->getOperand(0));
+ Assert1(false,
+ "invalid behavior operand in module flag (unexpected constant)",
+ Op->getOperand(0));
+ }
MDString *ID = dyn_cast<MDString>(Op->getOperand(1));
- Assert1(Behavior,
- "invalid behavior operand in module flag (expected constant integer)",
- Op->getOperand(0));
- unsigned BehaviorValue = Behavior->getZExtValue();
Assert1(ID,
"invalid ID operand in module flag (expected metadata string)",
Op->getOperand(1));
// Sanity check the values for behaviors with additional requirements.
- switch (BehaviorValue) {
- default:
- Assert1(false,
- "invalid behavior operand in module flag (unexpected constant)",
- Op->getOperand(0));
- break;
-
+ switch (MFB) {
case Module::Error:
case Module::Warning:
case Module::Override:
@@ -726,7 +725,7 @@
}
// Unless this is a "requires" flag, check the ID is unique.
- if (BehaviorValue != Module::Require) {
+ if (MFB != Module::Require) {
bool Inserted = SeenIDs.insert(std::make_pair(ID, Op)).second;
Assert1(Inserted,
"module flag identifiers must be unique (or of 'require' type)",