[SpecialCaseList] Use glob by default (#74809)

https://reviews.llvm.org/D154014 addes glob support and enables it when
`#!special-case-list-v2` is the first line. This patch makes the glob
support the default (faster than regex after
https://reviews.llvm.org/D156046) and switches to the deprecated regex
support if `#!special-case-list-v1` is the first line.

I have surveyed many ignore lists. All ignore lists I find only use
basic `*` `.` and don't use regex metacharacters such as `(` and `)`.
(As neither `src:` nor `fun:` benefits from using regex.)
They are unaffected by the transition (with a caution that regex
`src:x/a.pb.*` matches `x/axpbx` but glob `src:x/a.pb.*` doesn't).

There is no deprecating warning. If a user finds
`#!special-case-list-v1`, they shall read that the old syntax is
deprecated.

Link:
https://discourse.llvm.org/t/use-glob-instead-of-regex-for-specialcaselists/71666

clang/docs/SanitizerSpecialCaseList.rst

@@ -56,13 +56,18 @@ and lines starting with "#" are ignored.
 
 .. note::
 
-  In `D154014 <https://reviews.llvm.org/D154014>`_ we transitioned to using globs instead
-  of regexes to match patterns in special case lists. Since this was a
-  breaking change, we will temporarily support the original behavior using
-  regexes. If ``#!special-case-list-v2`` is the first line of the file, then
-  we will use the new behavior using globs. For more details, see
-  `this discourse post <https://discourse.llvm.org/t/use-glob-instead-of-regex-for-specialcaselists/71666>`_.
+  Prior to Clang 18, section names and entries described below use a variant of
+  regex where ``*`` is translated to ``.*``. Clang 18 (`D154014
+  <https://reviews.llvm.org/D154014>`) switches to glob and plans to remove
+  regex support in Clang 19.
 
+  For Clang 18, regex is supported if ``#!special-case-list-v1`` is the first
+  line of the file.
+
+  Many special case lists use ``.`` to indicate the literal character and do
+  not use regex metacharacters such as ``(``, ``)``. They are unaffected by the
+  regex to glob transition. For more details, see `this discourse post
+  <https://discourse.llvm.org/t/use-glob-instead-of-regex-for-specialcaselists/71666>`_.
 
 Section names are globs written in square brackets that denote
 which sanitizer the following entries apply to. For example, ``[address]``
@@ -80,7 +85,6 @@ tool-specific docs.
 
 .. code-block:: bash
 
-    #!special-case-list-v2
     # The line above is explained in the note above
     # Lines starting with # are ignored.
     # Turn off checks for the source file

llvm/lib/Support/SpecialCaseList.cpp

@@ -150,13 +150,12 @@ bool SpecialCaseList::parse(const MemoryBuffer *MB, std::string &Error) {
     return false;
   }
 
-  // In https://reviews.llvm.org/D154014 we transitioned to using globs instead
-  // of regexes to match patterns in special case lists. Since this was a
-  // breaking change, we will temporarily support the original behavior using
-  // regexes. If "#!special-case-list-v2" is the first line of the file, then
-  // we will use the new behavior using globs. For more details, see
+  // In https://reviews.llvm.org/D154014 we added glob support and planned to
+  // remove regex support in patterns. We temporarily support the original
+  // behavior using regexes if "#!special-case-list-v1" is the first line of the
+  // file. For more details, see
   // https://discourse.llvm.org/t/use-glob-instead-of-regex-for-specialcaselists/71666
-  bool UseGlobs = MB->getBuffer().starts_with("#!special-case-list-v2\n");
+  bool UseGlobs = !MB->getBuffer().starts_with("#!special-case-list-v1\n");
 
   for (line_iterator LineIt(*MB, /*SkipBlanks=*/true, /*CommentMarker=*/'#');
        !LineIt.is_at_eof(); LineIt++) {

llvm/unittests/Support/SpecialCaseListTest.cpp

@@ -25,8 +25,8 @@ class SpecialCaseListTest : public ::testing::Test {
                                                        std::string &Error,
                                                        bool UseGlobs = true) {
     auto S = List.str();
-    if (UseGlobs)
-      S = (Twine("#!special-case-list-v2\n") + S).str();
+    if (!UseGlobs)
+      S = (Twine("#!special-case-list-v1\n") + S).str();
     std::unique_ptr<MemoryBuffer> MB = MemoryBuffer::getMemBuffer(S);
     return SpecialCaseList::create(MB.get(), Error);
   }
@@ -46,8 +46,8 @@ class SpecialCaseListTest : public ::testing::Test {
     SmallString<64> Path;
     sys::fs::createTemporaryFile("SpecialCaseListTest", "temp", FD, Path);
     raw_fd_ostream OF(FD, true, true);
-    if (UseGlobs)
-      OF << "#!special-case-list-v2\n";
+    if (!UseGlobs)
+      OF << "#!special-case-list-v1\n";
     OF << Contents;
     OF.close();
     return std::string(Path.str());
@@ -70,10 +70,10 @@ TEST_F(SpecialCaseListTest, Basic) {
   EXPECT_FALSE(SCL->inSection("", "fun", "hello"));
   EXPECT_FALSE(SCL->inSection("", "src", "hello", "category"));
 
-  EXPECT_EQ(4u, SCL->inSectionBlame("", "src", "hello"));
-  EXPECT_EQ(5u, SCL->inSectionBlame("", "src", "bye"));
-  EXPECT_EQ(6u, SCL->inSectionBlame("", "src", "hi", "category"));
-  EXPECT_EQ(7u, SCL->inSectionBlame("", "src", "zzzz", "category"));
+  EXPECT_EQ(3u, SCL->inSectionBlame("", "src", "hello"));
+  EXPECT_EQ(4u, SCL->inSectionBlame("", "src", "bye"));
+  EXPECT_EQ(5u, SCL->inSectionBlame("", "src", "hi", "category"));
+  EXPECT_EQ(6u, SCL->inSectionBlame("", "src", "zzzz", "category"));
   EXPECT_EQ(0u, SCL->inSectionBlame("", "src", "hi"));
   EXPECT_EQ(0u, SCL->inSectionBlame("", "fun", "hello"));
   EXPECT_EQ(0u, SCL->inSectionBlame("", "src", "hello", "category"));
@@ -85,12 +85,12 @@ TEST_F(SpecialCaseListTest, CorrectErrorLineNumberWithBlankLine) {
                                          "\n"
                                          "[not valid\n",
                                          Error));
-  EXPECT_THAT(Error, StartsWith("malformed section header on line 4:"));
+  EXPECT_THAT(Error, StartsWith("malformed section header on line 3:"));
 
   EXPECT_EQ(nullptr, makeSpecialCaseList("\n\n\n"
                                          "[not valid\n",
                                          Error));
-  EXPECT_THAT(Error, StartsWith("malformed section header on line 5:"));
+  EXPECT_THAT(Error, StartsWith("malformed section header on line 4:"));
 }
 
 TEST_F(SpecialCaseListTest, SectionGlobErrorHandling) {
@@ -101,7 +101,7 @@ TEST_F(SpecialCaseListTest, SectionGlobErrorHandling) {
   EXPECT_EQ(makeSpecialCaseList("[[]", Error), nullptr);
   EXPECT_EQ(
       Error,
-      "malformed section at line 2: '[': invalid glob pattern, unmatched '['");
+      "malformed section at line 1: '[': invalid glob pattern, unmatched '['");
 
   EXPECT_EQ(makeSpecialCaseList("src:=", Error), nullptr);
   EXPECT_THAT(Error, HasSubstr("Supplied glob was blank"));
@@ -163,10 +163,10 @@ TEST_F(SpecialCaseListTest, Substring) {
 TEST_F(SpecialCaseListTest, InvalidSpecialCaseList) {
   std::string Error;
   EXPECT_EQ(nullptr, makeSpecialCaseList("badline", Error));
-  EXPECT_EQ("malformed line 2: 'badline'", Error);
+  EXPECT_EQ("malformed line 1: 'badline'", Error);
   EXPECT_EQ(nullptr, makeSpecialCaseList("src:bad[a-", Error));
   EXPECT_EQ(
-      "malformed glob in line 2: 'bad[a-': invalid glob pattern, unmatched '['",
+      "malformed glob in line 1: 'bad[a-': invalid glob pattern, unmatched '['",
       Error);
   std::vector<std::string> Files(1, "unexisting");
   EXPECT_EQ(nullptr,