[clang] Cleanup docs and code for legacy no_sanitize attributes (NFC). (#161311)

vonosmas · erichkeane · web-flow · commit 98766d288f0d · 2025-09-30T11:09:01.000-07:00
Update generated docs for legacy attributes: * no_sanitize_(address|thread|memory) * no_address_safety_analysis Those are older forms of no_sanitize("list", "of", "sanitizers") attribute. They were previously as various spellings of the same attribute, which made the auto-generated documentation confusing. Fix this by explicitly making them three different attributes. This would also allow to simplify the delegation to the new no_sanitize form slightly, as we can instead rely on auto-generated code to check that TSan and MSan can't be disabled for globals. **HTML docs before:** <img width="1004" height="1175" alt="rendered-docs-before" src="https://github.com/user-attachments/assets/407b5fc1-799c-4882-8ff8-44a5ef3cf4f1" /> **HTML docs after:** <img width="1098" height="1118" alt="rendered-docs-after" src="https://github.com/user-attachments/assets/236ca93f-25f8-4d58-95ac-ede95ce18d01" /> --------- Co-authored-by: Erich Keane <ekeane@nvidia.com>
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
@@ -583,6 +583,7 @@ Moved checkers
 
 Sanitizers
 ----------
+- Improved documentation for legacy ``no_sanitize`` attributes.
 
 Python Binding Changes
 ----------------------
diff --git a/clang/include/clang/Basic/Attr.td b/clang/include/clang/Basic/Attr.td
@@ -3921,16 +3921,31 @@ def NoSanitize : InheritableAttr {
   }];
 }
 
-// Attributes to disable a specific sanitizer. No new sanitizers should be added
+// Attribute to disable AddressSanitizer. No new spellings should be added
 // to this list; the no_sanitize attribute should be extended instead.
-def NoSanitizeSpecific : InheritableAttr {
+def NoSanitizeAddress : InheritableAttr {
   let Spellings = [GCC<"no_address_safety_analysis">,
-                   GCC<"no_sanitize_address">,
-                   GCC<"no_sanitize_thread">,
-                   Clang<"no_sanitize_memory">];
+                   GCC<"no_sanitize_address">];
   let Subjects = SubjectList<[Function, GlobalVar], ErrorDiag>;
-  let Documentation = [NoSanitizeAddressDocs, NoSanitizeThreadDocs,
-                       NoSanitizeMemoryDocs];
+  let Documentation = [NoSanitizeAddressDocs];
+  let ASTNode = 0;
+}
+
+// Attribute to disable ThreadSanitizer. No new spellings should be added
+// to this list; the no_sanitize attribute should be extended instead.
+def NoSanitizeThread : InheritableAttr {
+  let Spellings = [GCC<"no_sanitize_thread">];
+  let Subjects = SubjectList<[Function], ErrorDiag>;
+  let Documentation = [NoSanitizeThreadDocs];
+  let ASTNode = 0;
+}
+
+// Attribute to disable MemorySanitizer. No new spellings should be added
+// to this list; the no_sanitize attribute should be extended instead.
+def NoSanitizeMemory : InheritableAttr {
+  let Spellings = [Clang<"no_sanitize_memory">];
+  let Subjects = SubjectList<[Function], ErrorDiag>;
+  let Documentation = [NoSanitizeMemoryDocs];
   let ASTNode = 0;
 }
 
diff --git a/clang/include/clang/Basic/AttrDocs.td b/clang/include/clang/Basic/AttrDocs.td
@@ -13,16 +13,16 @@
 // version control.
 //
 // To run clang-tblgen to generate the .rst file:
-// clang-tblgen -gen-attr-docs -I <root>/llvm/tools/clang/include
-//   <root>/llvm/tools/clang/include/clang/Basic/Attr.td -o
-//   <root>/llvm/tools/clang/docs/AttributeReference.rst
+// clang-tblgen -gen-attr-docs -I <root>/clang/include
+//   <root>/clang/include/clang/Basic/Attr.td -o
+//   <root>/clang/docs/AttributeReference.rst
 //
 // To run sphinx to generate the .html files (note that sphinx-build must be
 // available on the PATH):
 // Windows (from within the clang\docs directory):
 //   make.bat html
-// Non-Windows (from within the clang\docs directory):
-//   sphinx-build -b html _build/html
+// Non-Windows (from within the clang/docs directory):
+//   sphinx-build -b html . _build/html
 
 def GlobalDocumentation {
   code Intro =[{..
@@ -3629,6 +3629,7 @@ instrumentations should not be applied.
 
 The attribute takes a list of string literals with the following accepted
 values:
+
 * all values accepted by ``-fno-sanitize=``;
 * ``coverage``, to disable SanitizerCoverage instrumentation.
 
diff --git a/clang/lib/Sema/SemaDeclAttr.cpp b/clang/lib/Sema/SemaDeclAttr.cpp
@@ -6361,19 +6361,8 @@ static void handleNoSanitizeAttr(Sema &S, Decl *D, const ParsedAttr &AL) {
                                               Sanitizers.size()));
 }
 
-static void handleNoSanitizeSpecificAttr(Sema &S, Decl *D,
-                                         const ParsedAttr &AL) {
-  StringRef AttrName = AL.getAttrName()->getName();
-  normalizeName(AttrName);
-  StringRef SanitizerName = llvm::StringSwitch<StringRef>(AttrName)
-                                .Case("no_address_safety_analysis", "address")
-                                .Case("no_sanitize_address", "address")
-                                .Case("no_sanitize_thread", "thread")
-                                .Case("no_sanitize_memory", "memory");
-  if (isGlobalVar(D) && SanitizerName != "address")
-    S.Diag(D->getLocation(), diag::err_attribute_wrong_decl_type)
-        << AL << AL.isRegularKeywordAttribute() << ExpectedFunction;
-
+static AttributeCommonInfo
+getNoSanitizeAttrInfo(const ParsedAttr &NoSanitizeSpecificAttr) {
   // FIXME: Rather than create a NoSanitizeSpecificAttr, this creates a
   // NoSanitizeAttr object; but we need to calculate the correct spelling list
   // index rather than incorrectly assume the index for NoSanitizeSpecificAttr
@@ -6383,11 +6372,32 @@ static void handleNoSanitizeSpecificAttr(Sema &S, Decl *D,
   // getSpelling() or prettyPrint() on the resulting semantic attribute object
   // without failing assertions.
   unsigned TranslatedSpellingIndex = 0;
-  if (AL.isStandardAttributeSyntax())
+  if (NoSanitizeSpecificAttr.isStandardAttributeSyntax())
     TranslatedSpellingIndex = 1;
 
-  AttributeCommonInfo Info = AL;
+  AttributeCommonInfo Info = NoSanitizeSpecificAttr;
   Info.setAttributeSpellingListIndex(TranslatedSpellingIndex);
+  return Info;
+}
+
+static void handleNoSanitizeAddressAttr(Sema &S, Decl *D,
+                                        const ParsedAttr &AL) {
+  StringRef SanitizerName = "address";
+  AttributeCommonInfo Info = getNoSanitizeAttrInfo(AL);
+  D->addAttr(::new (S.Context)
+                 NoSanitizeAttr(S.Context, Info, &SanitizerName, 1));
+}
+
+static void handleNoSanitizeThreadAttr(Sema &S, Decl *D, const ParsedAttr &AL) {
+  StringRef SanitizerName = "thread";
+  AttributeCommonInfo Info = getNoSanitizeAttrInfo(AL);
+  D->addAttr(::new (S.Context)
+                 NoSanitizeAttr(S.Context, Info, &SanitizerName, 1));
+}
+
+static void handleNoSanitizeMemoryAttr(Sema &S, Decl *D, const ParsedAttr &AL) {
+  StringRef SanitizerName = "memory";
+  AttributeCommonInfo Info = getNoSanitizeAttrInfo(AL);
   D->addAttr(::new (S.Context)
                  NoSanitizeAttr(S.Context, Info, &SanitizerName, 1));
 }
@@ -7513,8 +7523,14 @@ ProcessDeclAttribute(Sema &S, Scope *scope, Decl *D, const ParsedAttr &AL,
   case ParsedAttr::AT_NoSanitize:
     handleNoSanitizeAttr(S, D, AL);
     break;
-  case ParsedAttr::AT_NoSanitizeSpecific:
-    handleNoSanitizeSpecificAttr(S, D, AL);
+  case ParsedAttr::AT_NoSanitizeAddress:
+    handleNoSanitizeAddressAttr(S, D, AL);
+    break;
+  case ParsedAttr::AT_NoSanitizeThread:
+    handleNoSanitizeThreadAttr(S, D, AL);
+    break;
+  case ParsedAttr::AT_NoSanitizeMemory:
+    handleNoSanitizeMemoryAttr(S, D, AL);
     break;
   case ParsedAttr::AT_GuardedBy:
     handleGuardedByAttr(S, D, AL);
diff --git a/clang/test/Misc/pragma-attribute-supported-attributes-list.test b/clang/test/Misc/pragma-attribute-supported-attributes-list.test
@@ -126,7 +126,9 @@
 // CHECK-NEXT: NoProfileFunction (SubjectMatchRule_function)
 // CHECK-NEXT: NoRandomizeLayout (SubjectMatchRule_record)
 // CHECK-NEXT: NoSanitize (SubjectMatchRule_function, SubjectMatchRule_objc_method, SubjectMatchRule_variable_is_global)
-// CHECK-NEXT: NoSanitizeSpecific (SubjectMatchRule_function, SubjectMatchRule_variable_is_global)
+// CHECK-NEXT: NoSanitizeAddress (SubjectMatchRule_function, SubjectMatchRule_variable_is_global)
+// CHECK-NEXT: NoSanitizeMemory (SubjectMatchRule_function)
+// CHECK-NEXT: NoSanitizeThread (SubjectMatchRule_function)
 // CHECK-NEXT: NoSpeculativeLoadHardening (SubjectMatchRule_function, SubjectMatchRule_objc_method)
 // CHECK-NEXT: NoSplitStack (SubjectMatchRule_function)
 // CHECK-NEXT: NoStackProtector (SubjectMatchRule_function)
