[llvm-bugs] [Bug 53066] BreadthFirstIterator causes a crash

[LLVM Bugs via llvm-bugs]

Issue	53066
Summary	BreadthFirstIterator causes a crash
Labels	new issue
Assignees
Reporter	jirislaby

    Having this minimalistic checker plugin:
```cpp
#include <llvm/ADT/BreadthFirstIterator.h>

#include <clang/StaticAnalyzer/Core/Checker.h>
#include <clang/StaticAnalyzer/Core/CheckerManager.h>
#include <clang/StaticAnalyzer/Core/PathSensitive/AnalysisManager.h>
#include <clang/StaticAnalyzer/Frontend/CheckerRegistry.h>

using namespace clang;

class BFBeginChecker : public clang::ento::Checker<ento::check::ASTCodeBody> {
public:
        void checkASTCodeBody(const Decl *D, ento::AnalysisManager& mgr,
                        ento::BugReporter &BR) const {
                D->dumpColor();
                auto cfg = mgr.getCFG(D);
                cfg->dump(mgr.getLangOpts(), true);

                for (auto I = llvm::bf_begin(cfg); I != llvm::bf_end(cfg); ++I) {
                        auto b = *I;
                        llvm::errs() << "addr=" << b << " id=" << (b ? b->getBlockID() : -1) << "\n";
                        assert(b);
                }
        }
};

extern "C" const char clang_analyzerAPIVersionString[] = CLANG_ANALYZER_API_VERSION_STRING;

extern "C" void clang_registerCheckers(clang::ento::CheckerRegistry &registry) {
        registry.addChecker<BFBeginChecker>("BFBeginChecker", "Invokes bf_begin", "");
}
```
Compile and run it:
```sh
$ g++ -shared -fPIC -o bf_begin.so -I/usr/include -std=c++14   -fno-exceptions -D_GNU_SOURCE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -Wall -g bf_begin.cpp -lLLVM
$ clang -cc1 -load ./bf_begin.so -analyze -analyzer-checker=BFBeginChecker list.c
```
where list.c is:
```c
void X()
{
        do { } while (0);
}
```
I see:
```
FunctionDecl 0x858648 <list2.c:1:1, line:4:1> line:1:6 X 'void ()'
`-CompoundStmt 0x858780 <line:2:1, line:4:1>
  `-DoStmt 0x858760 <line:3:2, col:17>
    |-CompoundStmt 0x858730 <col:5, col:7>
    `-IntegerLiteral 0x858740 <col:16> 'int' 0

 [B3 (ENTRY)]
   Succs (1): B1

 [B1]
   1: 0
   T: do ... while [B1.1]
   Preds (2): B2 B3
   Succs (2): NULL B0

 [B2]
   Succs (1): B1

 [B0 (EXIT)]
   Preds (1): B1

addr=0x87bb28 id=3
addr=0x87b958 id=1
addr=0x0 id=4294967295
clang: bf_begin.cpp:21: void BFBeginChecker::checkASTCodeBody(const clang::Decl*, clang::ento::AnalysisManager&, clang::ento::BugReporter&) const: Assertion `b' failed.


```

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