[NoSanitizeList][NFI] Add containsPrefix to remove duplicated logics. (#142027)

See https://github.com/llvm/llvm-project/pull/142006 and
https://github.com/llvm/llvm-project/issues/139128

---------

Co-authored-by: Vitaly Buka <vitalybuka@google.com>

clang/include/clang/Basic/NoSanitizeList.h

diff --git a/clang/include/clang/Basic/NoSanitizeList.h b/clang/include/clang/Basic/NoSanitizeList.h
index 4341585..a7a7a29 100644
--- a/clang/include/clang/Basic/NoSanitizeList.h
+++ b/clang/include/clang/Basic/NoSanitizeList.h
@@ -29,6 +29,8 @@
 class NoSanitizeList {
   std::unique_ptr<SanitizerSpecialCaseList> SSCL;
   SourceManager &SM;
+  bool containsPrefix(SanitizerMask Mask, StringRef Prefix, StringRef Name,
+                      StringRef Category) const;
 
 public:
   NoSanitizeList(const std::vector<std::string> &NoSanitizeListPaths,

clang/lib/Basic/NoSanitizeList.cpp

diff --git a/clang/lib/Basic/NoSanitizeList.cpp b/clang/lib/Basic/NoSanitizeList.cpp
index 9f0f1c6..a1ca31e 100644
--- a/clang/lib/Basic/NoSanitizeList.cpp
+++ b/clang/lib/Basic/NoSanitizeList.cpp
@@ -27,6 +27,21 @@
 
 NoSanitizeList::~NoSanitizeList() = default;
 
+bool NoSanitizeList::containsPrefix(SanitizerMask Mask, StringRef Prefix,
+                                    StringRef Name, StringRef Category) const {
+  std::pair<unsigned, unsigned> NoSan =
+      SSCL->inSectionBlame(Mask, Prefix, Name, Category);
+  if (NoSan == llvm::SpecialCaseList::NotFound)
+    return false;
+  std::pair<unsigned, unsigned> San =
+      SSCL->inSectionBlame(Mask, Prefix, Name, "sanitize");
+  // The statement evaluates to true under the following conditions:
+  // 1. The string "prefix:*=sanitize" is absent.
+  // 2. If "prefix:*=sanitize" is present, its (File Index, Line Number) is less
+  // than that of "prefix:*".
+  return San == llvm::SpecialCaseList::NotFound || NoSan > San;
+}
+
 bool NoSanitizeList::containsGlobal(SanitizerMask Mask, StringRef GlobalName,
                                     StringRef Category) const {
   return SSCL->inSection(Mask, "global", GlobalName, Category);
@@ -34,11 +49,7 @@
 
 bool NoSanitizeList::containsType(SanitizerMask Mask, StringRef MangledTypeName,
                                   StringRef Category) const {
-  auto NoSan = SSCL->inSectionBlame(Mask, "type", MangledTypeName, Category);
-  if (NoSan == llvm::SpecialCaseList::NotFound)
-    return false;
-  auto San = SSCL->inSectionBlame(Mask, "type", MangledTypeName, "sanitize");
-  return San == llvm::SpecialCaseList::NotFound || NoSan > San;
+  return containsPrefix(Mask, "type", MangledTypeName, Category);
 }
 
 bool NoSanitizeList::containsFunction(SanitizerMask Mask,
@@ -48,11 +59,7 @@
 
 bool NoSanitizeList::containsFile(SanitizerMask Mask, StringRef FileName,
                                   StringRef Category) const {
-  auto NoSan = SSCL->inSectionBlame(Mask, "src", FileName, Category);
-  if (NoSan == llvm::SpecialCaseList::NotFound)
-    return false;
-  auto San = SSCL->inSectionBlame(Mask, "src", FileName, "sanitize");
-  return San == llvm::SpecialCaseList::NotFound || NoSan > San;
+  return containsPrefix(Mask, "src", FileName, Category);
 }
 
 bool NoSanitizeList::containsMainFile(SanitizerMask Mask, StringRef FileName,