[llvm] [Verifier] Check function attributes related to branch protection (NFC) (PR #70565)

[Momchil Velikov via llvm-commits]

https://github.com/momchil-velikov updated https://github.com/llvm/llvm-project/pull/70565

>From 4c3297ffc83ce337afb644b8be5763b6363fc486 Mon Sep 17 00:00:00 2001
From: Momchil Velikov <momchil.velikov at arm.com>
Date: Sat, 28 Oct 2023 15:01:36 +0100
Subject: [PATCH 1/3] [Verifier] Check function attributes related to branch
 protection (NFC)

---
 llvm/lib/IR/Verifier.cpp | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/llvm/lib/IR/Verifier.cpp b/llvm/lib/IR/Verifier.cpp
index 396af600b8dab29..863d77656478fd8 100644
--- a/llvm/lib/IR/Verifier.cpp
+++ b/llvm/lib/IR/Verifier.cpp
@@ -2231,6 +2231,27 @@ void Verifier::verifyFunctionAttrs(FunctionType *FT, AttributeList Attrs,
   checkUnsignedBaseTenFuncAttr(Attrs, "patchable-function-prefix", V);
   checkUnsignedBaseTenFuncAttr(Attrs, "patchable-function-entry", V);
   checkUnsignedBaseTenFuncAttr(Attrs, "warn-stack-size", V);
+
+  if (Attrs.hasFnAttr("sign-return-adress")) {
+    StringRef S = Attrs.getFnAttr("sign-return-adress").getValueAsString();
+    if (S != "none" && S != "all" && S != "non-leaf")
+      CheckFailed("invalid value for 'sign-return-adress' attribute: " + S, V);
+  }
+
+  if (Attrs.hasFnAttr("sign-return-adress-key")) {
+    StringRef S = Attrs.getFnAttr("sign-return-adress-key").getValueAsString();
+    if (!S.equals_insensitive("a_key") && !S.equals_insensitive("b_key"))
+      CheckFailed("invalid value for 'sign-return-adress-key' attribute: " + S,
+                  V);
+  }
+
+  if (Attrs.hasFnAttr("branch-target-enforcement")) {
+    StringRef S =
+        Attrs.getFnAttr("branch-target-enforcement").getValueAsString();
+    if (!S.equals_insensitive("true") && !S.equals_insensitive("false"))
+      CheckFailed(
+          "invalid value for 'branch-target-enforcement' attribute: " + S, V);
+  }
 }
 
 void Verifier::verifyFunctionMetadata(

>From ded25c35f0138e7bd0c5522eb9a553fa9501f1b1 Mon Sep 17 00:00:00 2001
From: Momchil Velikov <momchil.velikov at arm.com>
Date: Mon, 30 Oct 2023 09:27:08 +0000
Subject: [PATCH 2/3] Fix typos, do attribute lookup once

---
 llvm/lib/IR/Verifier.cpp | 17 ++++++++---------
 1 file changed, 8 insertions(+), 9 deletions(-)

diff --git a/llvm/lib/IR/Verifier.cpp b/llvm/lib/IR/Verifier.cpp
index 863d77656478fd8..a966e64a0a6d6f3 100644
--- a/llvm/lib/IR/Verifier.cpp
+++ b/llvm/lib/IR/Verifier.cpp
@@ -2232,22 +2232,21 @@ void Verifier::verifyFunctionAttrs(FunctionType *FT, AttributeList Attrs,
   checkUnsignedBaseTenFuncAttr(Attrs, "patchable-function-entry", V);
   checkUnsignedBaseTenFuncAttr(Attrs, "warn-stack-size", V);
 
-  if (Attrs.hasFnAttr("sign-return-adress")) {
-    StringRef S = Attrs.getFnAttr("sign-return-adress").getValueAsString();
+  if (auto A = Attrs.getFnAttr("sign-return-address"); A.isValid()) {
+    StringRef S = A.getValueAsString();
     if (S != "none" && S != "all" && S != "non-leaf")
-      CheckFailed("invalid value for 'sign-return-adress' attribute: " + S, V);
+      CheckFailed("invalid value for 'sign-return-address' attribute: " + S, V);
   }
 
-  if (Attrs.hasFnAttr("sign-return-adress-key")) {
-    StringRef S = Attrs.getFnAttr("sign-return-adress-key").getValueAsString();
+  if (auto A = Attrs.getFnAttr("sign-return-address-key"); A.isValid()) {
+    StringRef S = A.getValueAsString();
     if (!S.equals_insensitive("a_key") && !S.equals_insensitive("b_key"))
-      CheckFailed("invalid value for 'sign-return-adress-key' attribute: " + S,
+      CheckFailed("invalid value for 'sign-return-address-key' attribute: " + S,
                   V);
   }
 
-  if (Attrs.hasFnAttr("branch-target-enforcement")) {
-    StringRef S =
-        Attrs.getFnAttr("branch-target-enforcement").getValueAsString();
+  if (auto A = Attrs.getFnAttr("branch-target-enforcement"); A.isValid()) {
+    StringRef S = A.getValueAsString();
     if (!S.equals_insensitive("true") && !S.equals_insensitive("false"))
       CheckFailed(
           "invalid value for 'branch-target-enforcement' attribute: " + S, V);

>From ba2fdb44867ab833c500eabfef810d860c7aa099 Mon Sep 17 00:00:00 2001
From: Momchil Velikov <momchil.velikov at arm.com>
Date: Mon, 30 Oct 2023 10:34:26 +0000
Subject: [PATCH 3/3] Add a test

---
 llvm/test/Verifier/branch-prot-attrs.ll | 13 +++++++++++++
 1 file changed, 13 insertions(+)
 create mode 100644 llvm/test/Verifier/branch-prot-attrs.ll

diff --git a/llvm/test/Verifier/branch-prot-attrs.ll b/llvm/test/Verifier/branch-prot-attrs.ll
new file mode 100644
index 000000000000000..123a8207cfe6b4f
--- /dev/null
+++ b/llvm/test/Verifier/branch-prot-attrs.ll
@@ -0,0 +1,13 @@
+; RUN: not llvm-as %s -o /dev/null 2>&1 | FileCheck %s
+
+define void @f() #0 {
+  ret void
+}
+
+attributes #0 = {
+; CHECK:  invalid value for 'sign-return-address' attribute: loaf
+  "sign-return-address"="loaf"
+; CHECK: invalid value for 'sign-return-address-key' attribute: bad-mkey
+  "sign-return-address-key"="bad-mkey"
+; CHECK:   invalid value for 'branch-target-enforcement' attribute: yes-please
+  "branch-target-enforcement"="yes-please" }