Simplification of libcall like printf->puts must check for RtLibUseGOT metadata.

With -fno-plt, for example, calls to printf when getting converted to puts
still use the PLT. This patch checks for the metadata "RtLibUseGOT" and
annotates the declaration with the right attributes.

Differential Revision: https://reviews.llvm.org/D45180

llvm-svn: 329768

1 files changed, 11 insertions, 0 deletions

diff --git a/llvm/lib/Transforms/Utils/BuildLibCalls.cpp b/llvm/lib/Transforms/Utils/BuildLibCalls.cpp
index d4cf03c326d..24af7c463f4 100644
--- a/llvm/lib/Transforms/Utils/BuildLibCalls.cpp
+++ b/llvm/lib/Transforms/Utils/BuildLibCalls.cpp
@@ -105,12 +105,23 @@ static bool setRetNonNull(Function &F) {
   return true;
 }
 
+static bool setNonLazyBind(Function &F) {
+  if (F.hasFnAttribute(Attribute::NonLazyBind))
+    return false;
+  F.addFnAttr(Attribute::NonLazyBind);
+  return true;
+}
+
 bool llvm::inferLibFuncAttributes(Function &F, const TargetLibraryInfo &TLI) {
   LibFunc TheLibFunc;
   if (!(TLI.getLibFunc(F, TheLibFunc) && TLI.has(TheLibFunc)))
     return false;
 
   bool Changed = false;
+
+  if (F.getParent() != nullptr && F.getParent()->getRtLibUseGOT())
+    Changed |= setNonLazyBind(F);
+
   switch (TheLibFunc) {
   case LibFunc_strlen:
   case LibFunc_wcslen: