[FunctionAttrs][ArgumentPromotion][GlobalOpt] Disable some optimisations passes for naked functions

- Fix for bug 36078.
- Prevent the functionattrs, function-attrs, globalopt and argpromotion passes
  from changing naked functions.
- These passes can perform some alterations to the functions that should not be
  applied. An example is removing parameters that are seemingly not used because
  they are only referenced in the inline assembly. Another example is marking
  the function as fastcc.

llvm-svn: 325788

1 files changed, 4 insertions, 2 deletions

diff --git a/llvm/lib/Transforms/IPO/FunctionAttrs.cpp b/llvm/lib/Transforms/IPO/FunctionAttrs.cpp
index 5352e32479b..353daece48e 100644
--- a/llvm/lib/Transforms/IPO/FunctionAttrs.cpp
+++ b/llvm/lib/Transforms/IPO/FunctionAttrs.cpp
@@ -1136,7 +1136,8 @@ PreservedAnalyses PostOrderFunctionAttrsPass::run(LazyCallGraph::SCC &C,
   bool HasUnknownCall = false;
   for (LazyCallGraph::Node &N : C) {
     Function &F = N.getFunction();
-    if (F.hasFnAttribute(Attribute::OptimizeNone)) {
+    if (F.hasFnAttribute(Attribute::OptimizeNone) ||
+        F.hasFnAttribute(Attribute::Naked)) {
       // Treat any function we're trying not to optimize as if it were an
       // indirect call and omit it from the node set used below.
       HasUnknownCall = true;
@@ -1221,7 +1222,8 @@ static bool runImpl(CallGraphSCC &SCC, AARGetterT AARGetter) {
   bool ExternalNode = false;
   for (CallGraphNode *I : SCC) {
     Function *F = I->getFunction();
-    if (!F || F->hasFnAttribute(Attribute::OptimizeNone)) {
+    if (!F || F->hasFnAttribute(Attribute::OptimizeNone) ||
+        F->hasFnAttribute(Attribute::Naked)) {
       // External node or function we're trying not to optimize - we both avoid
       // transform them and avoid leveraging information they provide.
       ExternalNode = true;