[UBSan] Move type:*=sanitize handling.

[qinkunbao]

As discussed in #139128, this PR moves =sanitize handling from ASTContext::isTypeIgnoredBySanitizer to NoSanitizeList::containsType.

Before this PR: "=sanitize" has priority regardless of the order
After this PR: If multiple entries match the source, than the latest entry takes the precedence.

[llvmbot]

@llvm/pr-subscribers-clang

Author: Qinkun Bao (qinkunbao)

Changes

---

Full diff: https://github.com/llvm/llvm-project/pull/142006.diff

2 Files Affected:

• (modified) clang/lib/AST/ASTContext.cpp (+1-2)
• (modified) clang/lib/Basic/NoSanitizeList.cpp (+5-1)

diff --git a/clang/lib/AST/ASTContext.cpp b/clang/lib/AST/ASTContext.cpp
index e71928ec0dc1c..5044d7c33ec3c 100644
--- a/clang/lib/AST/ASTContext.cpp
+++ b/clang/lib/AST/ASTContext.cpp
@@ -875,8 +875,7 @@ ASTContext::insertCanonicalTemplateTemplateParmDeclInternal(
 bool ASTContext::isTypeIgnoredBySanitizer(const SanitizerMask &Mask,
                                           const QualType &Ty) const {
   std::string TyName = Ty.getUnqualifiedType().getAsString(getPrintingPolicy());
-  return NoSanitizeL->containsType(Mask, TyName) &&
-         !NoSanitizeL->containsType(Mask, TyName, "sanitize");
+  return NoSanitizeL->containsType(Mask, TyName);
 }
 
 TargetCXXABI::Kind ASTContext::getCXXABIKind() const {
diff --git a/clang/lib/Basic/NoSanitizeList.cpp b/clang/lib/Basic/NoSanitizeList.cpp
index a3ca463fc8efb..61ee19555c0ca 100644
--- a/clang/lib/Basic/NoSanitizeList.cpp
+++ b/clang/lib/Basic/NoSanitizeList.cpp
@@ -34,7 +34,11 @@ bool NoSanitizeList::containsGlobal(SanitizerMask Mask, StringRef GlobalName,
 
 bool NoSanitizeList::containsType(SanitizerMask Mask, StringRef MangledTypeName,
                                   StringRef Category) const {
-  return SSCL->inSection(Mask, "type", MangledTypeName, Category);
+  auto NoSan = SSCL->inSectionBlame(Mask, "type", FileName, Category);
+  if (NoSan == llvm::SpecialCaseList::NotFound)
+    return false;
+  auto San = SSCL->inSectionBlame(Mask, "type", FileName, "sanitize");
+  return San == llvm::SpecialCaseList::NotFound || NoSan > San;
 }
 
 bool NoSanitizeList::containsFunction(SanitizerMask Mask,

[Copilot]

Pull Request Overview

This PR centralizes type sanitization logic by moving handling of the sanitize category into NoSanitizeList::containsType and simplifying the corresponding check in ASTContext.

• Relocates and extends sanitizer checks in NoSanitizeList::containsType using inSectionBlame and ordering comparison.
• Updates ASTContext::isTypeIgnoredBySanitizer to a single call to the revised containsType.

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
clang/lib/Basic/NoSanitizeList.cpp	Refactored containsType to use inSectionBlame and compare sections
clang/lib/AST/ASTContext.cpp	Simplified isTypeIgnoredBySanitizer to delegate to containsType

Comments suppressed due to low confidence (2)

clang/lib/Basic/NoSanitizeList.cpp:37

• [nitpick] Variable names NoSan and San are terse and may be unclear; consider more descriptive names like noSanitizePos and sanitizePos to improve readability.

auto NoSan = SSCL->inSectionBlame(Mask, "type", FileName, Category);

clang/lib/Basic/NoSanitizeList.cpp:35

• The updated logic in containsType, including the new sanitizer ordering behavior, should be covered by unit tests to validate correct handling of presence and ordering across different sections.

bool NoSanitizeList::containsType(SanitizerMask Mask, StringRef MangledTypeName,

[Copilot]

Pull Request Overview

This PR refactors sanitizer handling by moving type-specific “sanitize” checks into NoSanitizeList::containsType and simplifying ASTContext::isTypeIgnoredBySanitizer to delegate fully to that method.

• Update containsType to use blame indices for combined “type” and “sanitize” sections
• Remove redundant checks in ASTContext::isTypeIgnoredBySanitizer to rely on the new combined logic

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.

File	Description
clang/lib/Basic/NoSanitizeList.cpp	Implement combined sanitizer handling in containsType using inSectionBlame
clang/lib/AST/ASTContext.cpp	Simplify isTypeIgnoredBySanitizer to delegate to the updated containsType

Comments suppressed due to low confidence (2)

clang/lib/Basic/NoSanitizeList.cpp:34

• Consider adding unit tests for containsType covering both cases where the type is whitelisted, blacklisted, or overridden by the sanitize section to ensure the new logic behaves as expected.

bool NoSanitizeList::containsType(SanitizerMask Mask, StringRef MangledTypeName,

clang/lib/AST/ASTContext.cpp:878

• The containsType method signature expects a third Category argument. Either provide a default value in the declaration or update this call to pass the appropriate category string.

return NoSanitizeL->containsType(Mask, TyName);

[vitalybuka]

It does not let to add contributors into reviewers so just CC @JustinStitt

[vitalybuka]

maybe this code pattern can be extracted into private helper and used across other prefixes.

[qinkunbao]

Yeah, I had the same thought when I copied the code from "containsType" to "containsFile".

I am going to publish a followup PR to address the issue.

[JustinStitt]

It does not let to add contributors into reviewers so just CC @JustinStitt

thanks for CC. taking a look.

[JustinStitt]

LGTM (but I don't have official powers to Approve).

[JustinStitt]

PR looks good to me. Only quirk is NoSan > San. The autos slightly obscure the fact these are pair types. Thankfully, the FileIdx portion of the pair is properly mapped left-to-right alongside all the -fsanitize-ignorelist= arguments within SpecialCaseList::createInternal. This means we'll get the obvious behavior of most recent SCL file which is then further delineated by line number.

[qinkunbao]

Thanks for the review. Given this part is going to be refactored in #142027 , I am going to merge this PR and change "auto" to "std::pair<unsigned, unsigned>" in #142027