Donát Nagy b80024e0f4
[analyzer][NFCI] Remove ad-hoc program point tagging (#142980)
Previously some checkers attached explicitly created program point tags
to some of the exploded graph nodes that they created. In most of the
checkers this ad-hoc tagging only affected the debug dump of the
exploded graph (and they weren't too relevant for debugging) so this
commit removes them.

There were two checkers where the tagging _did_ have a functional role:
- In `RetainCountChecker` the presence of tags were checked by
`RefCountReportVisitor`.
- In `DynamicTypePropagation` the checker sometimes wanted to create two
identical nodes and had to apply an explicit tag on the second one to
avoid "caching out".
 
In these two situations I preserved the tags but switched to using
`SimpleProgramPointTag` instead of `CheckerProgramPointTag` because
`CheckerProgramPointTag` didn't provide enough benefits to justify its
existence.

Note that this commit depends on the earlier commit "[analyzer] Fix
tagging of PostAllocatorCall" ec96c0c072ef3f78813c378949c00e1c07aa44e5
and would introduce crashes when cherry-picked onto a branch that
doesn't contain that commit.

For more details about the background see the discourse thread
https://discourse.llvm.org/t/role-of-programpointtag-in-the-static-analyzer/

As a tangentially related changes, this commit also adds some comments
to document the surprising behavior of `CheckerContext::addTransition`
and an assertion in the constructor of `PathSensitiveBugReport` to get a
more readable crash dump in the case when the report is constructed with
`nullptr` as the `ErrorNode`. (This can happen due to "caching out".)
2025-06-06 14:34:47 +02:00

24 lines
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C++

//== Checker.cpp - Registration mechanism for checkers -----------*- C++ -*--=//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file defines Checker, used to create and register checkers.
//
//===----------------------------------------------------------------------===//
#include "clang/StaticAnalyzer/Core/Checker.h"
using namespace clang;
using namespace ento;
int ImplicitNullDerefEvent::Tag;
StringRef CheckerBase::getDebugTag() const { return getName(); }
void CheckerBackend::printState(raw_ostream &Out, ProgramStateRef State,
const char *NL, const char *Sep) const {}