[𝘀𝗽𝗿] initial version

Created using spr 1.3.7

Author: vitalybuka

clang/docs/ReleaseNotes.rst

@@ -69,6 +69,8 @@ Potentially Breaking Changes
   call the member ``operator delete`` instead of the expected global
   delete operator. The old behavior is retained under ``-fclang-abi-compat=21``
   flag.
+- Clang warning suppressions file, ``--warning-suppression-mappings=``, now will
+  use the last matching entry instead of the longest one.
 - Trailing null statements in GNU statement expressions are no longer
   ignored by Clang; they now result in a void type. Clang previously
   matched GCC's behavior, which was recently clarified to be incorrect.

clang/docs/WarningSuppressionMappings.rst

@@ -63,7 +63,7 @@ Format
 Warning suppression mappings uses the same format as
 :doc:`SanitizerSpecialCaseList`.
 
-Sections describe which diagnostic group's behaviour to change, e.g.
+Sections describe which diagnostic group's behavior to change, e.g.
 ``[unused]``. When a diagnostic is matched by multiple sections, the latest
 section takes precedence.
 
@@ -76,7 +76,7 @@ Source files are matched against these globs either:
 - as paths relative to the current working directory
 - as absolute paths.
 
-When a source file matches multiple globs in a section, the longest one takes
+When a source file matches multiple globs in a section, the last one takes
 precedence.
 
 .. code-block:: bash

clang/include/clang/Basic/Diagnostic.h

@@ -971,7 +971,7 @@ class DiagnosticsEngine : public RefCountedBase<DiagnosticsEngine> {
   /// diagnostics in specific files.
   /// Mapping file is expected to be a special case list with sections denoting
   /// diagnostic groups and `src` entries for globs to suppress. `emit` category
-  /// can be used to disable suppression. Longest glob that matches a filepath
+  /// can be used to disable suppression. The last glob that matches a filepath
   /// takes precedence. For example:
   ///   [unused]
   ///   src:clang/*

clang/lib/Basic/Diagnostic.cpp

@@ -588,15 +588,12 @@ bool WarningsSpecialCaseList::isDiagSuppressed(diag::kind DiagId,
 
   StringRef F = llvm::sys::path::remove_leading_dotslash(PLoc.getFilename());
 
-  StringRef LongestSup = DiagSection->getLongestMatch("src", F, "");
-  if (LongestSup.empty())
+  unsigned LastSup = DiagSection->getLastMatch("src", F, "");
+  if (LastSup == 0)
     return false;
 
-  StringRef LongestEmit = DiagSection->getLongestMatch("src", F, "emit");
-  if (LongestEmit.empty())
-    return true;
-
-  return LongestSup.size() > LongestEmit.size();
+  unsigned LastEmit = DiagSection->getLastMatch("src", F, "emit");
+  return LastSup > LastEmit;
 }
 
 bool DiagnosticsEngine::isSuppressedViaMapping(diag::kind DiagId,

clang/unittests/Basic/DiagnosticTest.cpp

@@ -294,7 +294,7 @@ TEST_F(SuppressionMappingTest, EmitCategoryIsExcluded) {
                                             locForFile("foo.cpp")));
 }
 
-TEST_F(SuppressionMappingTest, LongestMatchWins) {
+TEST_F(SuppressionMappingTest, LastMatchWins) {
   llvm::StringLiteral SuppressionMappingFile = R"(
   [unused]
   src:*clang/*
@@ -327,10 +327,8 @@ TEST_F(SuppressionMappingTest, LongShortMatch) {
 
   EXPECT_TRUE(Diags.isSuppressedViaMapping(diag::warn_unused_function,
                                            locForFile("test/t1.cpp")));
-
-  // FIXME: This is confusing.
-  EXPECT_TRUE(Diags.isSuppressedViaMapping(diag::warn_unused_function,
-                                           locForFile("lld/test/t2.cpp")));
+  EXPECT_FALSE(Diags.isSuppressedViaMapping(diag::warn_unused_function,
+                                            locForFile("lld/test/t2.cpp")));
 }
 
 TEST_F(SuppressionMappingTest, ShortLongMatch) {

llvm/include/llvm/Support/SpecialCaseList.h

@@ -218,11 +218,6 @@ class SpecialCaseList {
     LLVM_ABI unsigned getLastMatch(StringRef Prefix, StringRef Query,
                                    StringRef Category) const;
 
-    // Helper method to search by Prefix, Query, and Category. Returns
-    // matching rule, or empty string if there is no match.
-    LLVM_ABI StringRef getLongestMatch(StringRef Prefix, StringRef Query,
-                                       StringRef Category) const;
-
   private:
     friend class SpecialCaseList;
     LLVM_ABI void preprocess(bool OrderBySize);

llvm/lib/Support/SpecialCaseList.cpp

@@ -380,17 +380,4 @@ unsigned SpecialCaseList::Section::getLastMatch(StringRef Prefix,
   return LastLine;
 }
 
-StringRef SpecialCaseList::Section::getLongestMatch(StringRef Prefix,
-                                                    StringRef Query,
-                                                    StringRef Category) const {
-  StringRef LongestRule;
-  if (const Matcher *M = findMatcher(Prefix, Category)) {
-    M->match(Query, [&](StringRef Rule, unsigned) {
-      if (LongestRule.size() < Rule.size())
-        LongestRule = Rule;
-    });
-  }
-  return LongestRule;
-}
-
 } // namespace llvm