[clang] [analyzer] Fix tagging of PostAllocatorCall (PR #142132)

[via cfe-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang-static-analyzer-1

Author: Donát Nagy (NagyDonat)

<details>
<summary>Changes</summary>

By design the `Location` data member of a `CheckerContext` is always a `ProgramPoint` which is tagged with the currently active checker (note that all checker classes are subclasses of `ProgramPointTag`). This ensures that exploded nodes created by the checker are by default tagged by the checker object unless the checker specifies some other tag (e.g. a note tag) to the `addTransition`-like method that creates the node.

This was followed by all the `CheckerManager::runCheckersForXXX` methods, except for `runCheckerForNewAllocator`, where the implementation constructed the `PostAllocatorCall` program point without passing `checkFn.Checker` as the tag of the program point.

This commit elimintates this inconsistency and adds an assertion to the constructor of `CheckerContext` to ensure that this invariant will be upheld even if we e.g. add a new program point kind.

I strongly suspect that this is a non-functional change because program point tags are a vestigial feature in the codebase that barely affect anything -- but e.g. their presence affects the infamous node reclamation process, so I'm not marking this as NFC.

---
Full diff: https://github.com/llvm/llvm-project/pull/142132.diff


2 Files Affected:

- (modified) clang/include/clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h (+2) 
- (modified) clang/lib/StaticAnalyzer/Core/CheckerManager.cpp (+2-2) 


``````````diff
diff --git a/clang/include/clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h b/clang/include/clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h
index 63ca3efc6d228..aad71299ccdc1 100644
--- a/clang/include/clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h
+++ b/clang/include/clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h
@@ -51,6 +51,8 @@ class CheckerContext {
       wasInlined(wasInlined) {
     assert(Pred->getState() &&
            "We should not call the checkers on an empty state.");
+    assert(loc.getTag() && "The ProgramPoint associated with CheckerContext "
+                           "must be tagged with the active checker.");
   }
 
   AnalysisManager &getAnalysisManager() {
diff --git a/clang/lib/StaticAnalyzer/Core/CheckerManager.cpp b/clang/lib/StaticAnalyzer/Core/CheckerManager.cpp
index d2b7b2bfbb019..0fe677e4ee435 100644
--- a/clang/lib/StaticAnalyzer/Core/CheckerManager.cpp
+++ b/clang/lib/StaticAnalyzer/Core/CheckerManager.cpp
@@ -585,8 +585,8 @@ namespace {
                     NodeBuilder &Bldr, ExplodedNode *Pred) {
       llvm::TimeTraceScope TimeScope(
           checkerScopeName("Allocator", checkFn.Checker));
-      ProgramPoint L =
-          PostAllocatorCall(Call.getOriginExpr(), Pred->getLocationContext());
+      ProgramPoint L = PostAllocatorCall(
+          Call.getOriginExpr(), Pred->getLocationContext(), checkFn.Checker);
       CheckerContext C(Bldr, Eng, Pred, L, WasInlined);
       checkFn(cast<CXXAllocatorCall>(*Call.cloneWithState(Pred->getState())),
               C);

``````````

</details>


https://github.com/llvm/llvm-project/pull/142132