[InstrProf] Don't take the address of alwaysinline available_externally functions
Doing so breaks compilation of the following C program
(under -fprofile-instr-generate):
__attribute__((always_inline)) inline int foo() { return 0; }
int main() { return foo(); }
At link time, we fail because taking the address of an
available_externally function creates an undefined external reference,
which the TU cannot provide.
Emitting the function definition into the object file at all appears to
be a violation of the langref: "Globals with 'available_externally'
linkage are never emitted into the object file corresponding to the LLVM
module."
Differential Revision: https://reviews.llvm.org/D34134
llvm-svn: 305327
diff --git a/llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp b/llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp
index f83c930..37f88d5 100644
--- a/llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp
+++ b/llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp
@@ -343,14 +343,24 @@
static inline bool shouldRecordFunctionAddr(Function *F) {
// Check the linkage
+ bool HasAvailableExternallyLinkage = F->hasAvailableExternallyLinkage();
if (!F->hasLinkOnceLinkage() && !F->hasLocalLinkage() &&
- !F->hasAvailableExternallyLinkage())
+ !HasAvailableExternallyLinkage)
return true;
+
+ // A function marked 'alwaysinline' with available_externally linkage can't
+ // have its address taken. Doing so would create an undefined external ref to
+ // the function, which would fail to link.
+ if (HasAvailableExternallyLinkage &&
+ F->hasFnAttribute(Attribute::AlwaysInline))
+ return false;
+
// Prohibit function address recording if the function is both internal and
// COMDAT. This avoids the profile data variable referencing internal symbols
// in COMDAT.
if (F->hasLocalLinkage() && F->hasComdat())
return false;
+
// Check uses of this function for other than direct calls or invokes to it.
// Inline virtual functions have linkeOnceODR linkage. When a key method
// exists, the vtable will only be emitted in the TU where the key method