Enable only on windows

Author: DKLoehr

clang/unittests/Basic/DiagnosticTest.cpp

@@ -361,6 +361,8 @@ TEST_F(SuppressionMappingTest, ParsingRespectsOtherWarningOpts) {
   EXPECT_THAT(diags(), IsEmpty());
 }
 
+#ifdef _WIN32
+// We're only slash-agnostic on windows hosts
 TEST_F(SuppressionMappingTest, ForwardSlashMatchesBothDirections) {
   llvm::StringLiteral SuppressionMappingFile = R"(
   [unused]
@@ -383,4 +385,5 @@ TEST_F(SuppressionMappingTest, ForwardSlashMatchesBothDirections) {
   EXPECT_FALSE(Diags.isSuppressedViaMapping(
       diag::warn_unused_function, locForFile(R"(clang/lib/Sema/foo.h)")));
 }
+#endif
 } // namespace

llvm/docs/ReleaseNotes.md

@@ -165,9 +165,9 @@ Changes to BOLT
 Changes to Sanitizers
 ---------------------
 
-* The [sanitizer special case list format](https://clang.llvm.org/docs/SanitizerSpecialCaseList.html#format)
+* On windows hosts, the [sanitizer special case list format](https://clang.llvm.org/docs/SanitizerSpecialCaseList.html#format)
   now treats forward slashes as either a forward or a backslash, to handle
-  paths with mixed unix and window styles.
+  paths with mixed unix and windows styles.
 
 Other Changes
 -------------

llvm/include/llvm/Support/GlobPattern.h

@@ -35,7 +35,8 @@ namespace llvm {
 ///   expansions are not supported. If \p MaxSubPatterns is empty then
 ///   brace expansions are not supported and characters `{,}` are treated as
 ///   literals.
-/// * `/` matches both unix and windows path separators: `/` and `\`.
+/// * If IsSlashAgnostic is passed, `/` matches both unix and windows path
+///   separators: `/` and `\`.
 /// * `\` escapes the next character so it is treated as a literal.
 ///
 /// Some known edge cases are:

llvm/lib/Support/SpecialCaseList.cpp

@@ -18,6 +18,8 @@
 #include "llvm/Support/LineIterator.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/VirtualFileSystem.h"
+#include "llvm/TargetParser/Host.h"
+#include "llvm/TargetParser/Triple.h"
 #include <stdio.h>
 #include <string>
 #include <system_error>
@@ -57,10 +59,12 @@ Error SpecialCaseList::Matcher::insert(StringRef Pattern, unsigned LineNumber,
   auto Glob = std::make_unique<Matcher::Glob>();
   Glob->Name = Pattern.str();
   Glob->LineNo = LineNumber;
+  // Backslashes are valid in posix-style filenames.
+  bool IsSlashAgnostic = Triple(sys::getDefaultTargetTriple()).isOSWindows();
   // We must be sure to use the string in `Glob` rather than the provided
   // reference which could be destroyed before match() is called
   if (auto Err = GlobPattern::create(Glob->Name, /*MaxSubPatterns=*/1024,
-                                     /*IsSlashAgnostic=*/true)
+                                     /*IsSlashAgnostic=*/IsSlashAgnostic)
                      .moveInto(Glob->Pattern))
     return Err;
   Globs.push_back(std::move(Glob));