[AArch64] Generate .note.gnu.property based on module flags.

Flags of the module derived exclusively from the compiler flag `-mbranch-protection`.
The note is generated based on the module flags accordingly.
After this change in case of compile unit without function won't have
the .note.gnu.property if the compiler flag is not present [1].

[1] https://bugs.llvm.org/show_bug.cgi?id=46480

Reviewed By: chill

Differential Revision: https://reviews.llvm.org/D80791

diff --git a/llvm/lib/Target/AArch64/AArch64AsmPrinter.cpp b/llvm/lib/Target/AArch64/AArch64AsmPrinter.cpp
index 9cf9679..7c4a855 100644 (file)
--- a/llvm/lib/Target/AArch64/AArch64AsmPrinter.cpp
+++ b/llvm/lib/Target/AArch64/AArch64AsmPrinter.cpp
@@ -192,33 +192,16 @@ void AArch64AsmPrinter::emitStartOfAsmFile(Module &M) {
     return;
 
   // Assemble feature flags that may require creation of a note section.
-  unsigned Flags = ELF::GNU_PROPERTY_AARCH64_FEATURE_1_BTI |
-                   ELF::GNU_PROPERTY_AARCH64_FEATURE_1_PAC;
-
-  if (any_of(M, [](const Function &F) {
-        return !F.isDeclaration() &&
-               !F.hasFnAttribute("branch-target-enforcement");
-      })) {
-    Flags &= ~ELF::GNU_PROPERTY_AARCH64_FEATURE_1_BTI;
-  }
-
-  if ((Flags & ELF::GNU_PROPERTY_AARCH64_FEATURE_1_BTI) == 0 &&
-      any_of(M, [](const Function &F) {
-        return F.hasFnAttribute("branch-target-enforcement");
-      })) {
-    errs() << "warning: some functions compiled with BTI and some compiled "
-              "without BTI\n"
-           << "warning: not setting BTI in feature flags\n";
-  }
-
-  if (any_of(M, [](const Function &F) {
-        if (F.isDeclaration())
-          return false;
-        Attribute A = F.getFnAttribute("sign-return-address");
-        return !A.isStringAttribute() || A.getValueAsString() == "none";
-      })) {
-    Flags &= ~ELF::GNU_PROPERTY_AARCH64_FEATURE_1_PAC;
-  }
+  unsigned Flags = 0;
+  if (const auto *BTE = mdconst::extract_or_null<ConstantInt>(
+          M.getModuleFlag("branch-target-enforcement")))
+    if (BTE->getZExtValue())
+      Flags |= ELF::GNU_PROPERTY_AARCH64_FEATURE_1_BTI;
+
+  if (const auto *Sign = mdconst::extract_or_null<ConstantInt>(
+          M.getModuleFlag("sign-return-address")))
+    if (Sign->getZExtValue())
+      Flags |= ELF::GNU_PROPERTY_AARCH64_FEATURE_1_PAC;
 
   if (Flags == 0)
     return;

diff --git a/llvm/test/CodeGen/AArch64/note-gnu-property-pac-bti-0.ll b/llvm/test/CodeGen/AArch64/note-gnu-property-pac-bti-0.ll
index fdd1d63..b64fda7 100644 (file)
--- a/llvm/test/CodeGen/AArch64/note-gnu-property-pac-bti-0.ll
+++ b/llvm/test/CodeGen/AArch64/note-gnu-property-pac-bti-0.ll
@@ -6,6 +6,13 @@
 
 attributes #0 = { "branch-target-enforcement"="true" }
 
+!llvm.module.flags = !{!0, !1, !2, !3}
+
+!0 = !{i32 1, !"branch-target-enforcement", i32 1}
+!1 = !{i32 1, !"sign-return-address", i32 1}
+!2 = !{i32 1, !"sign-return-address-all", i32 0}
+!3 = !{i32 1, !"sign-return-address-with-bkey", i32 0}
+
 ; Both attributes present in a file with no functions.
 ; ASM:     .word       3221225472
 ; ASM-NEXT:    .word   4

diff --git a/llvm/test/CodeGen/AArch64/note-gnu-property-pac-bti-1.ll b/llvm/test/CodeGen/AArch64/note-gnu-property-pac-bti-1.ll
index 9757dec..4996d8e 100644 (file)
--- a/llvm/test/CodeGen/AArch64/note-gnu-property-pac-bti-1.ll
+++ b/llvm/test/CodeGen/AArch64/note-gnu-property-pac-bti-1.ll
@@ -3,12 +3,17 @@
 ; RUN: llc -mtriple=aarch64-linux %s -filetype=obj -o - |  \
 ; RUN:   llvm-readelf --notes - | FileCheck %s --check-prefix=OBJ
 
-define dso_local i32 @f() #0 {
+define dso_local i32 @f() {
 entry:
   ret i32 0
 }
 
-attributes #0 = { "branch-target-enforcement"="true" }
+!llvm.module.flags = !{!0, !1, !2, !3}
+
+!0 = !{i32 1, !"branch-target-enforcement", i32 1}
+!1 = !{i32 1, !"sign-return-address", i32 0}
+!2 = !{i32 1, !"sign-return-address-all", i32 0}
+!3 = !{i32 1, !"sign-return-address-with-bkey", i32 0}
 
 ; BTI attribute present
 ; ASM:     .word       3221225472

diff --git a/llvm/test/CodeGen/AArch64/note-gnu-property-pac-bti-2.ll b/llvm/test/CodeGen/AArch64/note-gnu-property-pac-bti-2.ll
index 71b3109..f765aeb 100644 (file)
--- a/llvm/test/CodeGen/AArch64/note-gnu-property-pac-bti-2.ll
+++ b/llvm/test/CodeGen/AArch64/note-gnu-property-pac-bti-2.ll
@@ -3,12 +3,17 @@
 ; RUN: llc -mtriple=aarch64-linux %s -filetype=obj -o - |  \
 ; RUN:   llvm-readelf --notes - | FileCheck %s --check-prefix=OBJ
 
-define dso_local i32 @f() #0 {
+define dso_local i32 @f() {
 entry:
   ret i32 0
 }
 
-attributes #0 = { "sign-return-address"="all" }
+!llvm.module.flags = !{!0, !1, !2, !3}
+
+!0 = !{i32 1, !"branch-target-enforcement", i32 0}
+!1 = !{i32 1, !"sign-return-address", i32 1}
+!2 = !{i32 1, !"sign-return-address-all", i32 0}
+!3 = !{i32 1, !"sign-return-address-with-bkey", i32 0}
 
 ; PAC attribute present
 ; ASM:     .word       3221225472

diff --git a/llvm/test/CodeGen/AArch64/note-gnu-property-pac-bti-3.ll b/llvm/test/CodeGen/AArch64/note-gnu-property-pac-bti-3.ll
index 5082fa0..f5ef65b 100644 (file)
--- a/llvm/test/CodeGen/AArch64/note-gnu-property-pac-bti-3.ll
+++ b/llvm/test/CodeGen/AArch64/note-gnu-property-pac-bti-3.ll
@@ -3,12 +3,17 @@
 ; RUN: llc -mtriple=aarch64-linux %s -filetype=obj -o - |  \
 ; RUN:   llvm-readelf --notes - | FileCheck %s --check-prefix=OBJ
 
-define dso_local i32 @f() #0 {
+define dso_local i32 @f() {
 entry:
   ret i32 0
 }
 
-attributes #0 = { "branch-target-enforcement"="true" "sign-return-address"="non-leaf" }
+!llvm.module.flags = !{!0, !1, !2, !3}
+
+!0 = !{i32 1, !"branch-target-enforcement", i32 1}
+!1 = !{i32 1, !"sign-return-address", i32 1}
+!2 = !{i32 1, !"sign-return-address-all", i32 0}
+!3 = !{i32 1, !"sign-return-address-with-bkey", i32 0}
 
 ; Both attribute present
 ; ASM:     .word       3221225472

diff --git a/llvm/test/CodeGen/AArch64/note-gnu-property-pac-bti-4.ll b/llvm/test/CodeGen/AArch64/note-gnu-property-pac-bti-4.ll
index 5d81669..67ad5f0 100644 (file)
--- a/llvm/test/CodeGen/AArch64/note-gnu-property-pac-bti-4.ll
+++ b/llvm/test/CodeGen/AArch64/note-gnu-property-pac-bti-4.ll
@@ -1,7 +1,5 @@
 ; RUN: llc -mtriple=aarch64-linux %s               -o - | \
 ; RUN:   FileCheck %s --check-prefix=ASM
-; RUN: llc -mtriple=aarch64-linux %s -filetype=obj -o - |  \
-; RUN:   llvm-readelf --notes - | FileCheck %s --check-prefix=OBJ
 
 define dso_local i32 @f() #0 {
 entry:
@@ -17,9 +15,12 @@ attributes #0 = { "branch-target-enforcement"="true" "sign-return-address"="non-
 
 attributes #1 = { "branch-target-enforcement"="true" }
 
-; Only the common atttribute (BTI)
-; ASM:     .word       3221225472
-; ASM-NEXT:    .word   4
-; ASM-NEXT:    .word   1
+!llvm.module.flags = !{!0, !1, !2, !3}
 
-; OBJ: Properties: aarch64 feature: BTI
+!0 = !{i32 1, !"branch-target-enforcement", i32 0}
+!1 = !{i32 1, !"sign-return-address", i32 0}
+!2 = !{i32 1, !"sign-return-address-all", i32 0}
+!3 = !{i32 1, !"sign-return-address-with-bkey", i32 0}
+
+; Note is not emited if module has no properties
+; ASM-NOT: .note.gnu.property
\ No newline at end of file

diff --git a/llvm/test/CodeGen/AArch64/note-gnu-property-pac-bti-5.ll b/llvm/test/CodeGen/AArch64/note-gnu-property-pac-bti-5.ll
deleted file mode 100644 (file)
index 942eb59..0000000
--- a/llvm/test/CodeGen/AArch64/note-gnu-property-pac-bti-5.ll
+++ /dev/null
@@ -1,26 +0,0 @@
-; RUN: llc -mtriple=aarch64-linux %s               -o - 2>&1 | \
-; RUN:   FileCheck %s --check-prefix=ASM
-; RUN: llc -mtriple=aarch64-linux %s -filetype=obj -o -      |  \
-; RUN:   llvm-readelf --notes - | FileCheck %s --check-prefix=OBJ
-
-define dso_local i32 @f() #0 {
-entry:
-  ret i32 0
-}
-
-define dso_local i32 @g() #1 {
-entry:
-  ret i32 0
-}
-
-attributes #0 = { "branch-target-enforcement"="true" "sign-return-address"="non-leaf" }
-
-attributes #1 = { "sign-return-address"="all" }
-
-; Only the common atttribute (PAC)
-; ASM: warning: not setting BTI in feature flags
-; ASM:     .word       3221225472
-; ASM-NEXT:    .word   4
-; ASM-NEXT:    .word   2
-
-; OBJ: Properties: aarch64 feature: PAC

diff --git a/llvm/test/CodeGen/AArch64/note-gnu-property-pac-bti-6.ll b/llvm/test/CodeGen/AArch64/note-gnu-property-pac-bti-6.ll
deleted file mode 100644 (file)
index 8fb550b..0000000
--- a/llvm/test/CodeGen/AArch64/note-gnu-property-pac-bti-6.ll
+++ /dev/null
@@ -1,22 +0,0 @@
-; RUN: llc -mtriple=aarch64-linux %s               -o - | \
-; RUN:   FileCheck %s --check-prefix=ASM
-; RUN: llc -mtriple=aarch64-linux %s -filetype=obj -o - |  \
-; RUN:   llvm-readelf -S - | FileCheck %s --check-prefix=OBJ
-
-define dso_local i32 @f() #0 {
-entry:
-  ret i32 0
-}
-
-define dso_local i32 @g() #1 {
-entry:
-  ret i32 0
-}
-
-attributes #0 = { "sign-return-address"="non-leaf" }
-
-attributes #1 = { "sign-return-address"="none" }
-
-; No common attribute, no note section
-; ASM-NOT: .note.gnu.property
-; OBJ-NOT: .note.gnu.property

diff --git a/llvm/test/CodeGen/AArch64/note-gnu-property-pac-bti-7.ll b/llvm/test/CodeGen/AArch64/note-gnu-property-pac-bti-7.ll
deleted file mode 100644 (file)
index 67f0b2b..0000000
--- a/llvm/test/CodeGen/AArch64/note-gnu-property-pac-bti-7.ll
+++ /dev/null
@@ -1,23 +0,0 @@
-; RUN: llc -mtriple=aarch64-linux %s               -o - 2>&1 | \
-; RUN:   FileCheck %s --check-prefix=ASM
-; RUN: llc -mtriple=aarch64-linux %s -filetype=obj -o -      |  \
-; RUN:   llvm-readelf -S - | FileCheck %s --check-prefix=OBJ
-
-define dso_local i32 @f() #0 {
-entry:
-  ret i32 0
-}
-
-define dso_local i32 @g() #1 {
-entry:
-  ret i32 0
-}
-
-attributes #0 = { "sign-return-address"="non-leaf" }
-
-attributes #1 = { "branch-target-enforcement"="true" }
-
-; No common attribute, no note section
-; ASM: warning: not setting BTI in feature flags
-; ASM-NOT: .note.gnu.property
-; OBJ-NOT: .note.gnu.property

diff --git a/llvm/test/CodeGen/AArch64/note-gnu-property-pac-bti-8.ll b/llvm/test/CodeGen/AArch64/note-gnu-property-pac-bti-8.ll
deleted file mode 100644 (file)
index 8549491..0000000
--- a/llvm/test/CodeGen/AArch64/note-gnu-property-pac-bti-8.ll
+++ /dev/null
@@ -1,21 +0,0 @@
-; RUN: llc -mtriple=aarch64-linux %s               -o - | \
-; RUN:   FileCheck %s --check-prefix=ASM
-; RUN: llc -mtriple=aarch64-linux %s -filetype=obj -o - | \
-; RUN:   llvm-readelf --notes - | FileCheck %s --check-prefix=OBJ
-
-define dso_local i32 @f() #0 {
-entry:
-  %r = tail call i32 @g()
-  ret i32 %r
-}
-
-declare dso_local i32 @g()
-
-attributes #0 = { "branch-target-enforcement"="true" }
-
-; Declarations don't prevent setting BTI
-; ASM:     .word       3221225472
-; ASM-NEXT:    .word   4
-; ASM-NEXT:    .word   1
-
-; OBJ: Properties: aarch64 feature: BTI