[ARM][AArch64] Change module flags values.

clang/lib/CodeGen/CodeGenModule.cpp

@@ -1171,22 +1171,29 @@ void CodeGenModule::Release() {
                               "tag-stack-memory-buildattr", 1);
 
   if (T.isARM() || T.isThumb() || T.isAArch64()) {
+    // Previously 1 is used and meant for the backed to derive the function
+    // attribute form it. 2 now means function attributes already set for all
+    // functions in this module, so no need to propagate those from the module
+    // flag. Value is only used in case of LTO module merge because the backend
+    // will see all required function attribute set already. Value is used
+    // before modules got merged. Any posive value means the feature is active
+    // and required binary markings need to be emit accordingly.
     if (LangOpts.BranchTargetEnforcement)
       getModule().addModuleFlag(llvm::Module::Min, "branch-target-enforcement",
-                                1);
+                                2);
     if (LangOpts.BranchProtectionPAuthLR)
       getModule().addModuleFlag(llvm::Module::Min, "branch-protection-pauth-lr",
-                                1);
+                                2);
     if (LangOpts.GuardedControlStack)
-      getModule().addModuleFlag(llvm::Module::Min, "guarded-control-stack", 1);
+      getModule().addModuleFlag(llvm::Module::Min, "guarded-control-stack", 2);
     if (LangOpts.hasSignReturnAddress())
-      getModule().addModuleFlag(llvm::Module::Min, "sign-return-address", 1);
+      getModule().addModuleFlag(llvm::Module::Min, "sign-return-address", 2);
     if (LangOpts.isSignReturnAddressScopeAll())
       getModule().addModuleFlag(llvm::Module::Min, "sign-return-address-all",
-                                1);
+                                2);
     if (!LangOpts.isSignReturnAddressWithAKey())
       getModule().addModuleFlag(llvm::Module::Min,
-                                "sign-return-address-with-bkey", 1);
+                                "sign-return-address-with-bkey", 2);
   }
 
   if (CodeGenOpts.StackClashProtector)

clang/test/CodeGen/aarch64-sign-return-address.c

@@ -22,17 +22,17 @@
 // NONE-NOT:  !"branch-target-enforcement"
 // ALL-NOT:   !"branch-target-enforcement"
 // PART-NOT:  !"branch-target-enforcement"
-// BTE:       !{i32 8, !"branch-target-enforcement", i32 1}
+// BTE:       !{i32 8, !"branch-target-enforcement", i32 2}
 // B-KEY-NOT: !"branch-target-enforcement"
 
 // NONE-NOT:  !"sign-return-address"
-// ALL:   !{i32 8, !"sign-return-address", i32 1}
-// PART:  !{i32 8, !"sign-return-address", i32 1}
+// ALL:   !{i32 8, !"sign-return-address", i32 2}
+// PART:  !{i32 8, !"sign-return-address", i32 2}
 // BTE-NOT:   !"sign-return-address"
-// B-KEY: !{i32 8, !"sign-return-address", i32 1}
+// B-KEY: !{i32 8, !"sign-return-address", i32 2}
 
 // NONE-NOT:  !"sign-return-address-all"
-// ALL:   !{i32 8, !"sign-return-address-all", i32 1}
+// ALL:   !{i32 8, !"sign-return-address-all", i32 2}
 // PART-NOT:  !"sign-return-address-all"
 // BTE-NOT:   !"sign-return-address-all"
 // B-KEY-NOT: !"sign-return-address-all"
@@ -41,6 +41,6 @@
 // ALL-NOT:   !"sign-return-address-with-bkey"
 // PART-NOT:  !"sign-return-address-with-bkey"
 // BTE-NOT:   !"sign-return-address-with-bkey"
-// B-KEY: !{i32 8, !"sign-return-address-with-bkey", i32 1}
+// B-KEY: !{i32 8, !"sign-return-address-with-bkey", i32 2}
 
 void foo() {}

clang/test/CodeGen/arm-branch-protection-attr-2.c

@@ -18,16 +18,16 @@
 // NONE-NOT: !"branch-target-enforcement"
 // PART-NOT: !"branch-target-enforcement"
 // ALL-NOT:  !"branch-target-enforcement"
-// BTE:      !{i32 8, !"branch-target-enforcement", i32 1}
+// BTE:      !{i32 8, !"branch-target-enforcement", i32 2}
 
 // NONE-NOT: !"sign-return-address"
-// PART:     !{i32 8, !"sign-return-address", i32 1}
-// ALL:      !{i32 8, !"sign-return-address", i32 1}
+// PART:     !{i32 8, !"sign-return-address", i32 2}
+// ALL:      !{i32 8, !"sign-return-address", i32 2}
 // BTE-NOT:  !"sign-return-address"
 
 // NONE-NOT: !"sign-return-address-all", i32 0}
 // PART-NOT: !"sign-return-address-all", i32 0}
-// ALL:      !{i32 8, !"sign-return-address-all", i32 1}
+// ALL:      !{i32 8, !"sign-return-address-all", i32 2}
 // BTE-NOT:  !"sign-return-address-all", i32 0}
 
 void foo() {}

clang/test/Frontend/arm-ignore-branch-protection-option.c

@@ -15,4 +15,4 @@ __attribute__((target("arch=cortex-m0"))) void f() {}
 // CHECK-NOT:  attributes { {{.*}} "branch-target-enforcement"
 
 /// Check that there are branch protection module attributes despite the warning.
-// CHECK: !{i32 8, !"branch-target-enforcement", i32 1}
+// CHECK: !{i32 8, !"branch-target-enforcement", i32 2}

lld/test/ELF/lto/aarch64_inline.ll

@@ -0,0 +1,71 @@
+; REQUIRES: aarch64
+;; Test verifies inlining happens cross module when module flags are upgraded
+;; by the thin-lto linker/IRMover.
+;; Regression test for #82763
+
+; RUN: split-file %s %t
+; RUN: opt -thinlto-bc -thinlto-split-lto-unit -unified-lto %t/foo.s -o %t/foo.o
+; RUN: opt -thinlto-bc -thinlto-split-lto-unit -unified-lto %t/bar.s -o %t/bar.o
+; RUN: opt -thinlto-bc -thinlto-split-lto-unit -unified-lto %t/main.s -o %t/main.o
+; RUN: ld.lld -O2 --lto=thin --entry=main %t/main.o %t/foo.o %t/bar.o -o %t/exe
+; RUN: llvm-objdump -d %t/exe | FileCheck %s
+
+
+; CHECK-LABEL:  <main>:
+; CHECK-NEXT:         pacibsp
+; CHECK-NEXT:         mov     w0, #0x23
+; CHECK-NEXT:         autibsp
+; CHECK-NEXT:         ret
+
+;--- foo.s
+target datalayout = "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128"
+target triple = "aarch64-unknown-linux-gnu"
+
+define dso_local noundef i32 @foo() local_unnamed_addr #0 {
+entry:
+  ret i32 34
+}
+
+attributes #0 = { mustprogress nofree norecurse nosync nounwind willreturn memory(none) }
+!llvm.module.flags = !{!0, !1, !2, !3 }
+!0 = !{i32 8, !"branch-target-enforcement", i32 1}
+!1 = !{i32 8, !"sign-return-address", i32 1}
+!2 = !{i32 8, !"sign-return-address-all", i32 1}
+!3 = !{i32 8, !"sign-return-address-with-bkey", i32 1}
+
+;--- bar.s
+target datalayout = "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128"
+target triple = "aarch64-unknown-linux-gnu"
+
+define dso_local noundef i32 @bar() local_unnamed_addr #0 {
+entry:
+  ret i32 1
+}
+
+attributes #0 = { mustprogress nofree norecurse nosync nounwind willreturn memory(none) "branch-target-enforcement"="true" "sign-return-address"="all" "sign-return-address-key"="b_key" }
+!llvm.module.flags = !{!0, !1, !2, !3 }
+!0 = !{i32 8, !"branch-target-enforcement", i32 2}
+!1 = !{i32 8, !"sign-return-address", i32 2}
+!2 = !{i32 8, !"sign-return-address-all", i32 2}
+!3 = !{i32 8, !"sign-return-address-with-bkey", i32 2}
+
+;--- main.s
+target datalayout = "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128"
+target triple = "aarch64-unknown-linux-gnu"
+
+declare i32 @foo();
+declare i32 @bar();
+
+define i32 @main() {
+entry:
+  %1 = call i32 @foo()
+  %2 = call i32 @bar()
+  %3 = add i32 %1, %2
+  ret i32 %3
+}
+
+!llvm.module.flags = !{!0, !1, !2, !3 }
+!0 = !{i32 8, !"branch-target-enforcement", i32 1}
+!1 = !{i32 8, !"sign-return-address", i32 1}
+!2 = !{i32 8, !"sign-return-address-all", i32 1}
+!3 = !{i32 8, !"sign-return-address-with-bkey", i32 1}

llvm/include/llvm/IR/AutoUpgrade.h

@@ -88,6 +88,9 @@ namespace llvm {
   /// info. Return true if module is modified.
   bool UpgradeDebugInfo(Module &M);
 
+  /// Copies module attributes to the functions in the module.
+  void CopyModuleAttrToFunctions(Module &M);
+
   /// Check whether a string looks like an old loop attachment tag.
   inline bool mayBeOldLoopAttachmentTag(StringRef Name) {
     return Name.starts_with("llvm.vectorizer.");

llvm/lib/IR/AutoUpgrade.cpp

@@ -5178,6 +5178,58 @@ void llvm::UpgradeFunctionAttributes(Function &F) {
     Arg.removeAttrs(AttributeFuncs::typeIncompatible(Arg.getType()));
 }
 
+// Check if the module attribute is present and set to one.
+static bool isModuleAttributeOne(Module &M, const StringRef &ModAttr) {
+  const auto *Attr =
+      mdconst::extract_or_null<ConstantInt>(M.getModuleFlag(ModAttr));
+  return Attr && Attr->isOne();
+}
+
+// Check if the function attribute is not present and set it.
+static void SetFunctionAttrIfNotSet(Function &F, StringRef FnAttrName,
+                                    StringRef Value) {
+  if (!F.hasFnAttribute(FnAttrName))
+    F.addFnAttr(FnAttrName, Value);
+}
+
+void llvm::CopyModuleAttrToFunctions(Module &M) {
+  Triple T(M.getTargetTriple());
+  if (!T.isThumb() && !T.isARM() && !T.isAArch64())
+    return;
+
+  bool BTE = isModuleAttributeOne(M, "branch-target-enforcement");
+  bool BPPLR = isModuleAttributeOne(M, "branch-protection-pauth-lr");
+  bool GCS = isModuleAttributeOne(M, "guarded-control-stack");
+  bool SRA = isModuleAttributeOne(M, "sign-return-address");
+
+  if (!BTE && !BPPLR && !GCS && !SRA)
+    return;
+
+  StringRef SignTypeValue = "non-leaf";
+  if (SRA && isModuleAttributeOne(M, "sign-return-address-all"))
+    SignTypeValue = "all";
+
+  StringRef SignKeyValue = "a_key";
+  if (SRA && isModuleAttributeOne(M, "sign-return-address-with-bkey"))
+    SignKeyValue = "b_key";
+
+  for (Function &F : M.getFunctionList()) {
+    if (F.isDeclaration())
+      continue;
+
+    if (SRA) {
+      SetFunctionAttrIfNotSet(F, "sign-return-address", SignTypeValue);
+      SetFunctionAttrIfNotSet(F, "sign-return-address-key", SignKeyValue);
+    }
+    if (BTE)
+      SetFunctionAttrIfNotSet(F, "branch-target-enforcement", "true");
+    if (BPPLR)
+      SetFunctionAttrIfNotSet(F, "branch-protection-pauth-lr", "true");
+    if (GCS)
+      SetFunctionAttrIfNotSet(F, "guarded-control-stack", "true");
+  }
+}
+
 static bool isOldLoopArgument(Metadata *MD) {
   auto *T = dyn_cast_or_null<MDTuple>(MD);
   if (!T)

llvm/lib/Linker/IRMover.cpp

@@ -1623,6 +1623,11 @@ Error IRLinker::run() {
   // Loop over all of the linked values to compute type mappings.
   computeTypeMapping();
 
+  // Convert module level attributes to function level attributes because
+  // after merging modules the attributes might change and would have different
+  // effect on the functions as the original module would have.
+  CopyModuleAttrToFunctions(*SrcM);
+
   std::reverse(Worklist.begin(), Worklist.end());
   while (!Worklist.empty()) {
     GlobalValue *GV = Worklist.back();
@@ -1787,6 +1792,11 @@ IRMover::IRMover(Module &M) : Composite(M) {
   for (const auto *MD : StructTypes.getVisitedMetadata()) {
     SharedMDs[MD].reset(const_cast<MDNode *>(MD));
   }
+
+  // Convert module level attributes to function level attributes because
+  // after merging modules the attributes might change and would have different
+  // effect on the functions as the original module would have.
+  CopyModuleAttrToFunctions(M);
 }
 
 Error IRMover::move(std::unique_ptr<Module> Src,

llvm/test/LTO/AArch64/Inputs/bar.ll

@@ -0,0 +1,22 @@
+target datalayout = "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128"
+target triple = "aarch64-unknown-linux-gnu"
+
+define dso_local void @bar() #0 {
+entry:
+  ret void
+}
+
+define dso_local void @baz() #1 {
+entry:
+  ret void
+}
+
+attributes #0 = { noinline nounwind optnone uwtable }
+attributes #1 = { noinline nounwind optnone uwtable "branch-target-enforcement"="true" }
+
+!llvm.module.flags = !{!0, !1, !2, !3}
+
+!0 = !{i32 8, !"branch-target-enforcement", i32 2}
+!1 = !{i32 8, !"sign-return-address", i32 2}
+!2 = !{i32 8, !"sign-return-address-all", i32 2}
+!3 = !{i32 8, !"sign-return-address-with-bkey", i32 2}

llvm/test/LTO/AArch64/link-branch-target-enforcement.ll

@@ -30,8 +30,11 @@ entry:
 
 ; CHECK-NOT: linking module flags 'branch-target-enforcement': IDs have conflicting values in
 ; CHECK-DUMP: <main>:
+; CHECK-DUMP:      paciasp
+; CHECK-DUMP:      str
 ; CHECK-DUMP:      bl      0x8 <main+0x8>
 ; CHECK-DUMP: <foo>:
+; CHECK-DUMP:     pacibsp
 
 ; `main` doesn't support BTI while `foo` does, so in the binary
 ; we should see only PAC which is supported by both.

llvm/test/LTO/AArch64/link-sign-return-address.ll

@@ -0,0 +1,56 @@
+; Testcase to check that module with different sign return address can
+; be mixed.
+;
+; RUN: llvm-as %s -o %t1.bc
+; RUN: llvm-as %p/Inputs/foo.ll -o %t2.bc
+; RUN: llvm-as %p/Inputs/bar.ll -o %t3.bc
+; RUN: llvm-lto -exported-symbol main \
+; RUN:          -exported-symbol foo \
+; RUN:          -filetype=obj \
+; RUN:           %t3.bc %t2.bc %t1.bc \
+; RUN:           -o %t1.exe 2>&1
+; RUN: llvm-objdump -d %t1.exe | FileCheck --check-prefix=CHECK-DUMP %s
+; RUN: llvm-readelf -n %t1.exe | FileCheck --allow-empty --check-prefix=CHECK-PROP %s
+
+target datalayout = "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128"
+target triple = "aarch64-unknown-linux-gnu"
+
+declare i32 @foo();
+declare void @baz();
+declare void @bar();
+
+define i32 @main() {
+entry:
+  %add = call i32 @foo()
+  call void @bar()
+  call void @baz()
+  ret i32 %add
+}
+
+!llvm.module.flags = !{!0, !1, !2, !3 }
+!0 = !{i32 8, !"branch-target-enforcement", i32 0}
+!1 = !{i32 8, !"sign-return-address", i32 0}
+!2 = !{i32 8, !"sign-return-address-all", i32 0}
+!3 = !{i32 8, !"sign-return-address-with-bkey", i32 0}
+
+
+; CHECK-DUMP: <bar>:
+; CHECK-DUMP:     ret
+; CHECK-DUMP: <baz>:
+; CHECK-DUMP:     bti     c
+; CHECK-DUMP:     ret
+; CHECK-DUMP: <foo>:
+; CHECK-DUMP:     pacibsp
+; CHECK-DUMP:     mov     w0, #0x2a
+; CHECK-DUMP:     autibsp
+; CHECK-DUMP:     ret
+; CHECK-DUMP: <main>:
+; CHECK-DUMP-NOT:  paciasp
+; CHECK-DUMP:      str     x30,
+; CHECK-DUMP:      bl      0x20 <main+0x4>
+; CHECK-DUMP:      bl      0x0 <bar>
+; CHECK-DUMP:      bl      0x4 <baz>
+
+; `main` doesn't support PAC sign-return-address while `foo` does, so in the binary
+; we should not see anything.
+; CHECK-PROP-NOT:   Properties: aarch64 feature: PAC

llvm/test/Linker/link-arm-and-thumb.ll

@@ -13,11 +13,11 @@ entry:
   ret i32 %add
 }
 
-; CHECK: define i32 @main() {
+; CHECK: define i32 @main()
 ; CHECK: define i32 @foo(i32 %a, i32 %b) [[ARM_ATTRS:#[0-9]+]]
 ; CHECK: define i32 @bar(i32 %a, i32 %b) [[THUMB_ATTRS:#[0-9]+]]
 
-; CHECK: attributes [[ARM_ATTRS]] = { "target-features"="-thumb-mode" }
-; CHECK: attributes [[THUMB_ATTRS]] = { "target-features"="+thumb-mode" }
+; CHECK: attributes [[ARM_ATTRS]] = {{{.*}}"target-features"="-thumb-mode" }
+; CHECK: attributes [[THUMB_ATTRS]] = {{{.*}}"target-features"="+thumb-mode" }
 
 ; STDERR-NOT: warning: Linking two modules of different target triples: