[llvm-branch-commits] [clang] release/23.x: [NFC][clang][Serialization] Fix std::set_difference sorting mismatch in ASTReader (#219053) (PR #219097)

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llvmorg-github-actions[bot] wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang-modules

Author: llvmbot

<details>
<summary>Changes</summary>

Backport dc222c2de55988f5359262a0e29fed5c14e824e7

Requested by: @<!-- -->ChuanqiXu9

---
Full diff: https://github.com/llvm/llvm-project/pull/219097.diff


2 Files Affected:

- (modified) clang/lib/Serialization/ASTReader.cpp (+9-4) 
- (modified) clang/test/Modules/merge-target-features.cpp (+22) 


``````````diff
diff --git a/clang/lib/Serialization/ASTReader.cpp b/clang/lib/Serialization/ASTReader.cpp
index 4d3816d686730..1a437f3ebab98 100644
--- a/clang/lib/Serialization/ASTReader.cpp
+++ b/clang/lib/Serialization/ASTReader.cpp
@@ -523,13 +523,18 @@ static bool checkTargetOptions(const TargetOptions &TargetOpts,
 
   // We compute the set difference in both directions explicitly so that we can
   // diagnose the differences differently.
+  auto FeatureLess = [](StringRef A, StringRef B) {
+    return A.substr(1) < B.substr(1);
+  };
+
   SmallVector<StringRef, 4> UnmatchedExistingFeatures, UnmatchedReadFeatures;
-  std::set_difference(
-      ExistingFeatures.begin(), ExistingFeatures.end(), ReadFeatures.begin(),
-      ReadFeatures.end(), std::back_inserter(UnmatchedExistingFeatures));
+  std::set_difference(ExistingFeatures.begin(), ExistingFeatures.end(),
+                      ReadFeatures.begin(), ReadFeatures.end(),
+                      std::back_inserter(UnmatchedExistingFeatures),
+                      FeatureLess);
   std::set_difference(ReadFeatures.begin(), ReadFeatures.end(),
                       ExistingFeatures.begin(), ExistingFeatures.end(),
-                      std::back_inserter(UnmatchedReadFeatures));
+                      std::back_inserter(UnmatchedReadFeatures), FeatureLess);
 
   // If we are allowing compatible differences and the read feature set is
   // a strict subset of the existing feature set, there is nothing to diagnose.
diff --git a/clang/test/Modules/merge-target-features.cpp b/clang/test/Modules/merge-target-features.cpp
index c3678cbea11cb..f008492b7e341 100644
--- a/clang/test/Modules/merge-target-features.cpp
+++ b/clang/test/Modules/merge-target-features.cpp
@@ -148,6 +148,28 @@
 // RUN:   -fsyntax-only merge-target-features.cpp 2>&1 \
 // RUN:   | FileCheck --allow-empty --check-prefix=IGNORED2 %s
 // IGNORED2-NOT: error:
+//
+// RUN: %clang_cc1 -fmodules -x c++ -fmodules-cache-path=%t \
+// RUN:   -iquote Inputs/merge-target-features \
+// RUN:   -fno-implicit-modules \
+// RUN:   -fmodule-map-file-home-is-cwd \
+// RUN:   -emit-module -fmodule-name=foo -o %t/foo-order.pcm \
+// RUN:   -triple i386-unknown-unknown \
+// RUN:   -target-cpu i386 -target-feature -cx16 -target-feature +sse2 \
+// RUN:   Inputs/merge-target-features/module.modulemap
+//
+// RUN: not %clang_cc1 -fmodules -x c++ -fmodules-cache-path=%t \
+// RUN:   -iquote Inputs/merge-target-features \
+// RUN:   -fno-implicit-modules \
+// RUN:   -fmodule-map-file-home-is-cwd \
+// RUN:   -fmodule-map-file=Inputs/merge-target-features/module.modulemap \
+// RUN:   -fmodule-file=%t/foo-order.pcm \
+// RUN:   -triple i386-unknown-unknown \
+// RUN:   -target-cpu i386 -target-feature +sse2 \
+// RUN:   -fsyntax-only merge-target-features.cpp 2>&1 \
+// RUN:   | FileCheck --check-prefix=ORDER --implicit-check-not=error: %s
+// ORDER: error: precompiled file '{{.*}}foo-order.pcm' was compiled with the target feature '-cx16' but the current translation unit is not
+// ORDER: error: {{.*}} configuration mismatch
 
 #include "foo.h"
 

``````````

</details>


https://github.com/llvm/llvm-project/pull/219097