Provide a way to specify inliner's attribute compatibility and merging.

This reapplies r252990 and r252949. I've added member function getKind
to the Attr classes which returns the enum or string of the attribute.

Original commit message for r252949:

Provide a way to specify inliner's attribute compatibility and merging
rules using table-gen. NFC.

This commit adds new classes CompatRule and MergeRule to Attributes.td,
which are used to generate code to check attribute compatibility and
merge attributes of the caller and callee.

rdar://problem/19836465

llvm-svn: 256277

1 files changed, 78 insertions, 0 deletions

diff --git a/llvm/lib/IR/Attributes.cpp b/llvm/lib/IR/Attributes.cpp
index 2b8f67f24df..bcf7dc365ce 100644
--- a/llvm/lib/IR/Attributes.cpp
+++ b/llvm/lib/IR/Attributes.cpp
@@ -14,6 +14,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/IR/Attributes.h"
+#include "llvm/IR/Function.h"
 #include "AttributeImpl.h"
 #include "LLVMContextImpl.h"
 #include "llvm/ADT/STLExtras.h"
@@ -1431,3 +1432,80 @@ AttrBuilder AttributeFuncs::typeIncompatible(Type *Ty) {
 
   return Incompatible;
 }
+
+template<typename AttrClass>
+static bool isEqual(const Function &Caller, const Function &Callee) {
+  return Caller.getFnAttribute(AttrClass::getKind()) ==
+         Callee.getFnAttribute(AttrClass::getKind());
+}
+
+/// \brief Compute the logical AND of the attributes of the caller and the
+/// callee.
+///
+/// This function sets the caller's attribute to false if the callee's attribute
+/// is false.
+template<typename AttrClass>
+static void setAND(Function &Caller, const Function &Callee) {
+  if (AttrClass::isSet(Caller, AttrClass::getKind()) &&
+      !AttrClass::isSet(Callee, AttrClass::getKind()))
+    AttrClass::set(Caller, AttrClass::getKind(), false);
+}
+
+/// \brief Compute the logical OR of the attributes of the caller and the
+/// callee.
+///
+/// This function sets the caller's attribute to true if the callee's attribute
+/// is true.
+template<typename AttrClass>
+static void setOR(Function &Caller, const Function &Callee) {
+  if (!AttrClass::isSet(Caller, AttrClass::getKind()) &&
+      AttrClass::isSet(Callee, AttrClass::getKind()))
+    AttrClass::set(Caller, AttrClass::getKind(), true);
+}
+
+/// \brief If the inlined function had a higher stack protection level than the
+/// calling function, then bump up the caller's stack protection level.
+static void adjustCallerSSPLevel(Function &Caller, const Function &Callee) {
+  // If upgrading the SSP attribute, clear out the old SSP Attributes first.
+  // Having multiple SSP attributes doesn't actually hurt, but it adds useless
+  // clutter to the IR.
+  AttrBuilder B;
+  B.addAttribute(Attribute::StackProtect)
+    .addAttribute(Attribute::StackProtectStrong)
+    .addAttribute(Attribute::StackProtectReq);
+  AttributeSet OldSSPAttr = AttributeSet::get(Caller.getContext(),
+                                              AttributeSet::FunctionIndex,
+                                              B);
+
+  if (Callee.hasFnAttribute(Attribute::SafeStack)) {
+    Caller.removeAttributes(AttributeSet::FunctionIndex, OldSSPAttr);
+    Caller.addFnAttr(Attribute::SafeStack);
+  } else if (Callee.hasFnAttribute(Attribute::StackProtectReq) &&
+             !Caller.hasFnAttribute(Attribute::SafeStack)) {
+    Caller.removeAttributes(AttributeSet::FunctionIndex, OldSSPAttr);
+    Caller.addFnAttr(Attribute::StackProtectReq);
+  } else if (Callee.hasFnAttribute(Attribute::StackProtectStrong) &&
+             !Caller.hasFnAttribute(Attribute::SafeStack) &&
+             !Caller.hasFnAttribute(Attribute::StackProtectReq)) {
+    Caller.removeAttributes(AttributeSet::FunctionIndex, OldSSPAttr);
+    Caller.addFnAttr(Attribute::StackProtectStrong);
+  } else if (Callee.hasFnAttribute(Attribute::StackProtect) &&
+             !Caller.hasFnAttribute(Attribute::SafeStack) &&
+             !Caller.hasFnAttribute(Attribute::StackProtectReq) &&
+             !Caller.hasFnAttribute(Attribute::StackProtectStrong))
+    Caller.addFnAttr(Attribute::StackProtect);
+}
+
+#define GET_ATTR_COMPAT_FUNC
+#include "AttributesCompatFunc.inc"
+
+bool AttributeFuncs::areInlineCompatible(const Function &Caller,
+                                         const Function &Callee) {
+  return hasCompatibleFnAttrs(Caller, Callee);
+}
+
+
+void AttributeFuncs::mergeAttributesForInlining(Function &Caller,
+                                                const Function &Callee) {
+  mergeFnAttrs(Caller, Callee);
+}