[IPCP] Don't crash due to arg count/type mismatch between caller/callee
Summary:
This patch avoids an assert in IPConstantPropagation when
there is a argument count/type mismatch between the caller and
the callee.
While this is actually UB on C-level (clang emits a warning),
the IR verifier seems to accept it. I'm not sure what other
frontends/languages might think about this, so simply bailing out
to avoid hitting an assert (in CallSiteBase<>::getArgOperand or
Value::doRAUW) seems like a simple solution.
The problem is exposed by the fact that AbstractCallSites will look
through a bitcast at the callee position of a call/invoke.
Reviewers: jdoerfert, reames, efriedma
Reviewed By: jdoerfert, efriedma
Subscribers: eli.friedman, efriedma, llvm-commits
Differential Revision: https://reviews.llvm.org/D57052
llvm-svn: 352469
diff --git a/llvm/lib/Transforms/IPO/IPConstantPropagation.cpp b/llvm/lib/Transforms/IPO/IPConstantPropagation.cpp
index 8d51c6a..7dc4d9e 100644
--- a/llvm/lib/Transforms/IPO/IPConstantPropagation.cpp
+++ b/llvm/lib/Transforms/IPO/IPConstantPropagation.cpp
@@ -66,6 +66,13 @@
if (!ACS)
return false;
+ // Mismatched argument count is undefined behavior. Simply bail out to avoid
+ // handling of such situations below (avoiding asserts/crashes).
+ unsigned NumActualArgs = ACS.getNumArgOperands();
+ if (F.isVarArg() ? ArgumentConstants.size() > NumActualArgs
+ : ArgumentConstants.size() != NumActualArgs)
+ return false;
+
// Check out all of the potentially constant arguments. Note that we don't
// inspect varargs here.
Function::arg_iterator Arg = F.arg_begin();
@@ -78,6 +85,11 @@
Value *V = ACS.getCallArgOperand(i);
Constant *C = dyn_cast_or_null<Constant>(V);
+ // Mismatched argument type is undefined behavior. Simply bail out to avoid
+ // handling of such situations below (avoiding asserts/crashes).
+ if (C && Arg->getType() != C->getType())
+ return false;
+
// We can only propagate thread independent values through callbacks.
// This is different to direct/indirect call sites because for them we
// know the thread executing the caller and callee is the same. For