[Clang][ThreadSafety] Contextualize FieldDecl references in thread sa…

[Pranjal095]

…fety attribute arguments

This enables the thread safety handler to handle field references appropriately in attribute arguments by creating proper TIL representations for FieldDecl references in translateDeclRefExpr. Earlier, the analyzer treated the reference to the field name mu without the context required for it to match on this->mu, which led to a false positive in clang/test/SemaCXX/warn-thread-safety-analysis.cpp. That false positive is resolved with the changes made here.

I noticed this while working on PR#167048, when the added Clang spelling for guarded_by was failing to emulate the functionality of the corresponding GNU spelling due to the above reason.

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[llvmbot]

@llvm/pr-subscribers-clang

Author: Pranjal Prajapati (Pranjal095)

Changes

…fety attribute arguments

This enables the thread safety handler to handle field references appropriately in attribute arguments by creating proper TIL representations for FieldDecl references in translateDeclRefExpr. Earlier, the analyzer treated the reference to the field name mu without the context required for it to match on this->mu, which led to a false positive in clang/test/SemaCXX/warn-thread-safety-analysis.cpp. That false positive is resolved with the changes made here.

I noticed this while working on PR#167048, when the added Clang spelling for guarded_by was failing to emulate the functionality of the corresponding GNU spelling due to the above reason.

---

Full diff: https://github.com/llvm/llvm-project/pull/168028.diff

2 Files Affected:

• (modified) clang/lib/Analysis/ThreadSafetyCommon.cpp (+7)
• (modified) clang/test/SemaCXX/warn-thread-safety-analysis.cpp (-4)

diff --git a/clang/lib/Analysis/ThreadSafetyCommon.cpp b/clang/lib/Analysis/ThreadSafetyCommon.cpp
index ef48ae439c5f3..89a3087a59247 100644
--- a/clang/lib/Analysis/ThreadSafetyCommon.cpp
+++ b/clang/lib/Analysis/ThreadSafetyCommon.cpp
@@ -394,6 +394,13 @@ til::SExpr *SExprBuilder::translateDeclRefExpr(const DeclRefExpr *DRE,
   if (const auto *VarD = dyn_cast<VarDecl>(VD))
     return translateVariable(VarD, Ctx);
 
+  if (const auto *FD = dyn_cast<FieldDecl>(VD)) {
+    if (Ctx && Ctx->SelfArg) {
+      til::SExpr *E = new (Arena) til::SApply(SelfVar);
+      return new (Arena) til::Project(E, FD);
+    }
+  }
+
   // For non-local variables, treat it as a reference to a named object.
   return new (Arena) til::LiteralPtr(VD);
 }
diff --git a/clang/test/SemaCXX/warn-thread-safety-analysis.cpp b/clang/test/SemaCXX/warn-thread-safety-analysis.cpp
index 0e91639a271c5..f68699f701851 100644
--- a/clang/test/SemaCXX/warn-thread-safety-analysis.cpp
+++ b/clang/test/SemaCXX/warn-thread-safety-analysis.cpp
@@ -3590,14 +3590,10 @@ void requireDecl(RelockableScope &scope) {
 struct foo
 {
   Mutex mu;
-  // expected-note@+1{{see attribute on parameter here}}
   void require(RelockableScope &scope EXCLUSIVE_LOCKS_REQUIRED(mu));
   void callRequire(){
     RelockableScope scope(&mu);
-    // TODO: False positive due to incorrect parsing of parameter attribute arguments.
     require(scope);
-    // expected-warning@-1{{calling function 'require' requires holding mutex 'mu' exclusively}}
-    // expected-warning@-2{{mutex managed by 'scope' is 'mu' instead of 'mu'}}
   }
 };
 

[llvmbot]

@llvm/pr-subscribers-clang-analysis

Author: Pranjal Prajapati (Pranjal095)

Changes

…fety attribute arguments

This enables the thread safety handler to handle field references appropriately in attribute arguments by creating proper TIL representations for FieldDecl references in translateDeclRefExpr. Earlier, the analyzer treated the reference to the field name mu without the context required for it to match on this->mu, which led to a false positive in clang/test/SemaCXX/warn-thread-safety-analysis.cpp. That false positive is resolved with the changes made here.

I noticed this while working on PR#167048, when the added Clang spelling for guarded_by was failing to emulate the functionality of the corresponding GNU spelling due to the above reason.

---

Full diff: https://github.com/llvm/llvm-project/pull/168028.diff

2 Files Affected:

• (modified) clang/lib/Analysis/ThreadSafetyCommon.cpp (+7)
• (modified) clang/test/SemaCXX/warn-thread-safety-analysis.cpp (-4)

diff --git a/clang/lib/Analysis/ThreadSafetyCommon.cpp b/clang/lib/Analysis/ThreadSafetyCommon.cpp
index ef48ae439c5f3..89a3087a59247 100644
--- a/clang/lib/Analysis/ThreadSafetyCommon.cpp
+++ b/clang/lib/Analysis/ThreadSafetyCommon.cpp
@@ -394,6 +394,13 @@ til::SExpr *SExprBuilder::translateDeclRefExpr(const DeclRefExpr *DRE,
   if (const auto *VarD = dyn_cast<VarDecl>(VD))
     return translateVariable(VarD, Ctx);
 
+  if (const auto *FD = dyn_cast<FieldDecl>(VD)) {
+    if (Ctx && Ctx->SelfArg) {
+      til::SExpr *E = new (Arena) til::SApply(SelfVar);
+      return new (Arena) til::Project(E, FD);
+    }
+  }
+
   // For non-local variables, treat it as a reference to a named object.
   return new (Arena) til::LiteralPtr(VD);
 }
diff --git a/clang/test/SemaCXX/warn-thread-safety-analysis.cpp b/clang/test/SemaCXX/warn-thread-safety-analysis.cpp
index 0e91639a271c5..f68699f701851 100644
--- a/clang/test/SemaCXX/warn-thread-safety-analysis.cpp
+++ b/clang/test/SemaCXX/warn-thread-safety-analysis.cpp
@@ -3590,14 +3590,10 @@ void requireDecl(RelockableScope &scope) {
 struct foo
 {
   Mutex mu;
-  // expected-note@+1{{see attribute on parameter here}}
   void require(RelockableScope &scope EXCLUSIVE_LOCKS_REQUIRED(mu));
   void callRequire(){
     RelockableScope scope(&mu);
-    // TODO: False positive due to incorrect parsing of parameter attribute arguments.
     require(scope);
-    // expected-warning@-1{{calling function 'require' requires holding mutex 'mu' exclusively}}
-    // expected-warning@-2{{mutex managed by 'scope' is 'mu' instead of 'mu'}}
   }
 };