[llvm][Arm][AArch64] Do not inline a function with different signing …

…scheme.

If the signing scheme is different that maybe the functions assumes different behaviours and dangerous to inline them without analysing them.
This should be a rare case.

llvm/include/llvm/IR/Attributes.td

@@ -342,11 +342,18 @@ def DenormalFPMathF32 : ComplexStrAttr<"denormal-fp-math-f32", [FnAttr]>;
 class CompatRule<string F> {
   // The name of the function called to check the attribute of the caller and
   // callee and decide whether inlining should be allowed. The function's
-  // signature must match "bool(const Function&, const Function &)", where the
+  // signature must match "bool(const Function&, const Function&)", where the
   // first parameter is the reference to the caller and the second parameter is
   // the reference to the callee. It must return false if the attributes of the
   // caller and callee are incompatible, and true otherwise.
   string CompatFunc = F;
+  string AttrName = "";
+}
+
+class CompatRuleAttr<string F, string Attr> : CompatRule<F> {
+  // The checker function is extended with an third argument as the function attribute string.
+  // bool(const Function&, const Function&, const StringRef&)"
+  string AttrName = Attr;
 }
 
 def : CompatRule<"isEqual<SanitizeAddressAttr>">;
@@ -359,7 +366,10 @@ def : CompatRule<"isEqual<ShadowCallStackAttr>">;
 def : CompatRule<"isEqual<UseSampleProfileAttr>">;
 def : CompatRule<"isEqual<NoProfileAttr>">;
 def : CompatRule<"checkDenormMode">;
-
+def : CompatRule<"checkStrictFP">;
+def : CompatRuleAttr<"isEqual", "sign-return-address">;
+def : CompatRuleAttr<"isEqual", "sign-return-address-key">;
+def : CompatRuleAttr<"isEqual", "branch-protection-pauth-lr">;
 
 class MergeRule<string F> {
   // The name of the function called to merge the attributes of the caller and

llvm/lib/IR/Attributes.cpp

@@ -2039,12 +2039,24 @@ static bool checkDenormMode(const Function &Caller, const Function &Callee) {
   return false;
 }
 
+static bool checkStrictFP(const Function &Caller, const Function &Callee) {
+  // Do not inline strictfp function into non-strictfp one. It would require
+  // conversion of all FP operations in host function to constrained intrinsics.
+  return !(Callee.getAttributes().hasFnAttr(Attribute::StrictFP) &&
+           !Caller.getAttributes().hasFnAttr(Attribute::StrictFP));
+}
+
 template<typename AttrClass>
 static bool isEqual(const Function &Caller, const Function &Callee) {
   return Caller.getFnAttribute(AttrClass::getKind()) ==
          Callee.getFnAttribute(AttrClass::getKind());
 }
 
+static bool isEqual(const Function &Caller, const Function &Callee,
+                    const StringRef &AttrName) {
+  return Caller.getFnAttribute(AttrName) == Callee.getFnAttribute(AttrName);
+}
+
 /// Compute the logical AND of the attributes of the caller and the
 /// callee.
 ///

llvm/lib/Transforms/Utils/InlineFunction.cpp

@@ -2103,13 +2103,6 @@ llvm::InlineResult llvm::InlineFunction(CallBase &CB, InlineFunctionInfo &IFI,
   BasicBlock *OrigBB = CB.getParent();
   Function *Caller = OrigBB->getParent();
 
-  // Do not inline strictfp function into non-strictfp one. It would require
-  // conversion of all FP operations in host function to constrained intrinsics.
-  if (CalledFunc->getAttributes().hasFnAttr(Attribute::StrictFP) &&
-      !Caller->getAttributes().hasFnAttr(Attribute::StrictFP)) {
-    return InlineResult::failure("incompatible strictfp attributes");
-  }
-
   // GC poses two hazards to inlining, which only occur when the callee has GC:
   //  1. If the caller has no GC, then the callee's GC must be propagated to the
   //     caller.

llvm/test/Transforms/Inline/inline-sign-return-address.ll

@@ -0,0 +1,104 @@
+; Check the inliner doesn't inline a function with different sign return address schemes.
+; RUN: opt < %s -passes=inline -S | FileCheck %s
+
+define internal void @foo_all() #0 {
+  ret void
+}
+
+define internal void @foo_nonleaf() #1 {
+  ret void
+}
+
+define internal void @foo_none() #2 {
+  ret void
+}
+
+define internal void @foo_lr() #3 {
+  ret void
+}
+
+define internal void @foo_bkey() #4 {
+  ret void
+}
+
+define dso_local void @bar_all() #0 {
+; CHECK-LABEL: bar_all
+; CHECK-NOT:     call void @foo_all()
+; CHECK-NEXT:    call void @foo_nonleaf()
+; CHECK-NEXT:    call void @foo_none()
+; CHECK-NEXT:    call void @foo_lr()
+; CHECK-NEXT:    call void @foo_bkey()
+  call void @foo_all()
+  call void @foo_nonleaf()
+  call void @foo_none()
+  call void @foo_lr()
+  call void @foo_bkey()
+  ret void
+}
+
+define dso_local void @bar_nonleaf() #1 {
+; CHECK-LABEL: bar_nonleaf
+; CHECK-NEXT:    call void @foo_all()
+; CHECK-NOT:     call void @foo_nonleaf()
+; CHECK-NEXT:    call void @foo_none()
+; CHECK-NEXT:    call void @foo_lr()
+; CHECK-NEXT:    call void @foo_bkey()
+  call void @foo_all()
+  call void @foo_nonleaf()
+  call void @foo_none()
+  call void @foo_lr()
+  call void @foo_bkey()
+  ret void
+}
+
+define dso_local void @bar_none() #2 {
+; CHECK-LABEL: bar_none
+; CHECK-NEXT:    call void @foo_all()
+; CHECK-NEXT:    call void @foo_nonleaf()
+; CHECK-NOT:     call void @foo_none()
+; CHECK-NEXT:    call void @foo_lr()
+; CHECK-NEXT:    call void @foo_bkey()
+  call void @foo_all()
+  call void @foo_nonleaf()
+  call void @foo_none()
+  call void @foo_lr()
+  call void @foo_bkey()
+  ret void
+}
+
+define dso_local void @bar_lr() #3 {
+; CHECK-LABEL: bar_lr
+; CHECK-NEXT:    call void @foo_all()
+; CHECK-NEXT:    call void @foo_nonleaf()
+; CHECK-NEXT:    call void @foo_none()
+; CHECK-NOT:     call void @foo_lr()
+; CHECK-NEXT:    call void @foo_bkey()
+  call void @foo_all()
+  call void @foo_nonleaf()
+  call void @foo_none()
+  call void @foo_lr()
+  call void @foo_bkey()
+  ret void
+}
+
+define dso_local void @bar_bkey() #4 {
+; CHECK-LABEL: bar_bkey
+; CHECK-NEXT:    call void @foo_all()
+; CHECK-NEXT:    call void @foo_nonleaf()
+; CHECK-NEXT:    call void @foo_none()
+; CHECK-NEXT:    call void @foo_lr()
+; CHECK-NOT:     call void @foo_bkey()
+  call void @foo_all()
+  call void @foo_nonleaf()
+  call void @foo_none()
+  call void @foo_lr()
+  call void @foo_bkey()
+  ret void
+}
+
+
+attributes #0 = { "branch-protection-pauth-lr"="false" "sign-return-address"="all" }
+attributes #1 = { "branch-protection-pauth-lr"="false" "sign-return-address"="non-leaf" }
+attributes #2 = { "branch-protection-pauth-lr"="false" "sign-return-address"="none" }
+attributes #3 = { "branch-protection-pauth-lr"="true" "sign-return-address"="non-leaf" }
+attributes #4 = { "branch-protection-pauth-lr"="true" "sign-return-address"="non-leaf" "sign-return-address-key"="b_key" }

llvm/utils/TableGen/Attributes.cpp

@@ -87,7 +87,12 @@ void Attributes::emitFnAttrCompatCheck(raw_ostream &OS, bool IsStringAttr) {
 
   for (auto *Rule : CompatRules) {
     StringRef FuncName = Rule->getValueAsString("CompatFunc");
-    OS << "  Ret &= " << FuncName << "(Caller, Callee);\n";
+    StringRef AttrName = Rule->getValueAsString("AttrName");
+    if (AttrName.empty())
+      OS << "  Ret &= " << FuncName << "(Caller, Callee);\n";
+    else
+      OS << "  Ret &= " << FuncName << "(Caller, Callee, \"" << AttrName
+         << "\");\n";
   }
 
   OS << "\n";