[NFC][SpecialCaseList] Use BumpPtrAllocator to allocate patterns

[vitalybuka]

This simplifies structure of GlobMatcher, and
avoids "no copy/move" requirement.

[llvmbot]

@llvm/pr-subscribers-llvm-support

Author: Vitaly Buka (vitalybuka)

Changes

This simplifies structure of GlobMatcher, and
avoids "no copy/move" requirement.

---

Full diff: https://github.com/llvm/llvm-project/pull/162304.diff

2 Files Affected:

• (modified) llvm/include/llvm/Support/SpecialCaseList.h (+5-6)
• (modified) llvm/lib/Support/SpecialCaseList.cpp (+8-12)

diff --git a/llvm/include/llvm/Support/SpecialCaseList.h b/llvm/include/llvm/Support/SpecialCaseList.h
index eff36569fcab7..9b56cd8902e39 100644
--- a/llvm/include/llvm/Support/SpecialCaseList.h
+++ b/llvm/include/llvm/Support/SpecialCaseList.h
@@ -13,6 +13,7 @@
 #define LLVM_SUPPORT_SPECIALCASELIST_H
 
 #include "llvm/ADT/StringMap.h"
+#include "llvm/Support/Allocator.h"
 #include "llvm/Support/Compiler.h"
 #include "llvm/Support/GlobPattern.h"
 #include "llvm/Support/Regex.h"
@@ -134,16 +135,13 @@ class SpecialCaseList {
     LLVM_ABI unsigned match(StringRef Query) const;
     LLVM_ABI Error insert(StringRef Pattern, unsigned LineNumber);
     struct Glob {
-      std::string Name;
+      Glob(unsigned LineNo, GlobPattern &&Pattern)
+          : LineNo(LineNo), Pattern(std::move(Pattern)) {}
       unsigned LineNo;
       GlobPattern Pattern;
-      // neither copyable nor movable because GlobPattern contains
-      // Glob::StringRef that points to Glob::Name.
-      Glob(Glob &&) = delete;
-      Glob() = default;
     };
 
-    std::vector<std::unique_ptr<GlobMatcher::Glob>> Globs;
+    std::vector<GlobMatcher::Glob> Globs;
   };
 
   /// Represents a set of globs and their line numbers
@@ -175,6 +173,7 @@ class SpecialCaseList {
     unsigned FileIdx;
   };
 
+  BumpPtrAllocator StrAlloc;
   std::vector<Section> Sections;
 
   LLVM_ABI Expected<Section *> addSection(StringRef SectionStr,
diff --git a/llvm/lib/Support/SpecialCaseList.cpp b/llvm/lib/Support/SpecialCaseList.cpp
index 71f7b9aa65796..cd9b2f9b0cb28 100644
--- a/llvm/lib/Support/SpecialCaseList.cpp
+++ b/llvm/lib/Support/SpecialCaseList.cpp
@@ -62,26 +62,20 @@ unsigned SpecialCaseList::RegexMatcher::match(StringRef Query) const {
 
 Error SpecialCaseList::GlobMatcher::insert(StringRef Pattern,
                                            unsigned LineNumber) {
-  if (Pattern.empty()) {
+  if (Pattern.empty())
     return createStringError(errc::invalid_argument, "Supplied glob was blank");
-  }
 
-  auto Glob = std::make_unique<GlobMatcher::Glob>();
-  Glob->Name = Pattern.str();
-  Glob->LineNo = LineNumber;
-  // 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)
-                     .moveInto(Glob->Pattern))
+  auto Res = GlobPattern::create(Pattern, /*MaxSubPatterns=*/1024);
+  if (auto Err = Res.takeError())
     return Err;
-  Globs.push_back(std::move(Glob));
+  Globs.emplace_back(LineNumber, std::move(Res.get()));
   return Error::success();
 }
 
 unsigned SpecialCaseList::GlobMatcher::match(StringRef Query) const {
   for (const auto &Glob : reverse(Globs))
-    if (Glob->Pattern.match(Query))
-      return Glob->LineNo;
+    if (Glob.Pattern.match(Query))
+      return Glob.LineNo;
   return 0;
 }
 
@@ -159,6 +153,7 @@ SpecialCaseList::addSection(StringRef SectionStr, unsigned FileNo,
   Sections.emplace_back(SectionStr, FileNo, UseGlobs);
   auto &Section = Sections.back();
 
+  SectionStr = SectionStr.copy(StrAlloc);
   if (auto Err = Section.SectionMatcher.insert(SectionStr, LineNo)) {
     return createStringError(errc::invalid_argument,
                              "malformed section at line " + Twine(LineNo) +
@@ -220,6 +215,7 @@ bool SpecialCaseList::parse(unsigned FileIdx, const MemoryBuffer *MB,
     auto [Pattern, Category] = Postfix.split("=");
     auto [It, _] =
         CurrentSection->Entries[Prefix].try_emplace(Category, UseGlobs);
+    Pattern = Pattern.copy(StrAlloc);
     if (auto Err = It->second.insert(Pattern, LineNo)) {
       Error =
           (Twine("malformed ") + (UseGlobs ? "glob" : "regex") + " in line " +