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

[Donát Nagy via cfe-commits]

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

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.

>From baf602168326804e4fbcb0eae22b3c8a8db4eee0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Don=C3=A1t=20Nagy?= <donat.nagy at ericsson.com>
Date: Fri, 30 May 2025 14:22:40 +0200
Subject: [PATCH] [analyzer] Fix tagging of PostAllocatorCall

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.
---
 .../clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h  | 2 ++
 clang/lib/StaticAnalyzer/Core/CheckerManager.cpp              | 4 ++--
 2 files changed, 4 insertions(+), 2 deletions(-)

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);