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Backport "[analyzer] Fix inf recursion in StackAddrEscapeChecker for self referencing blocks" #11905

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Merged
steakhal merged 1 commit into from
Dec 4, 2025
Merged

Backport "[analyzer] Fix inf recursion in StackAddrEscapeChecker for self referencing blocks" #11905

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5 changes: 5 additions & 0 deletions clang/lib/StaticAnalyzer/Checkers/StackAddrEscapeChecker.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -22,6 +22,7 @@
#include "clang/StaticAnalyzer/Core/PathSensitive/MemRegion.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramState.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/Support/raw_ostream.h"
using namespace clang;
using namespace ento;
Expand Down Expand Up @@ -256,6 +257,7 @@ class FindStackRegionsSymbolVisitor final : public SymbolVisitor {
CheckerContext &Ctxt;
const StackFrameContext *PoppedStackFrame;
SmallVectorImpl<const MemRegion *> &EscapingStackRegions;
llvm::SmallPtrSet<const MemRegion *, 16> VisitedRegions;

public:
explicit FindStackRegionsSymbolVisitor(
Expand All @@ -267,6 +269,9 @@ class FindStackRegionsSymbolVisitor final : public SymbolVisitor {
bool VisitSymbol(SymbolRef sym) override { return true; }

bool VisitMemRegion(const MemRegion *MR) override {
if (!VisitedRegions.insert(MR).second)
return true;

SaveIfEscapes(MR);

if (const BlockDataRegion *BDR = MR->getAs<BlockDataRegion>())
Expand Down
15 changes: 13 additions & 2 deletions clang/test/Analysis/stackaddrleak.c
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@@ -1,5 +1,5 @@
// RUN: %clang_analyze_cc1 -analyzer-checker=core,unix.Malloc -verify -std=c99 -Dbool=_Bool -Wno-bool-conversion %s
// RUN: %clang_analyze_cc1 -analyzer-checker=core,unix.Malloc -verify -x c++ -Wno-bool-conversion %s
// RUN: %clang_analyze_cc1 -fblocks -analyzer-checker=core,unix.Malloc -verify -std=c99 -Dbool=_Bool -Wno-bool-conversion %s
// RUN: %clang_analyze_cc1 -fblocks -analyzer-checker=core,unix.Malloc -verify -x c++ -Wno-bool-conversion %s

typedef __INTPTR_TYPE__ intptr_t;
char const *p;
Expand Down Expand Up @@ -90,3 +90,14 @@ struct child_stack_context_s return_child_stack_context_field() {
}
return s; // expected-warning {{Address of stack memory associated with local variable 'a' returned to caller}}
}

// Returns an 'int' block taking an 'int'.
int (^copy_self_referencing_block(void))(int) {
// It is important that the 'fib' block captures itself.
__block int (^fib)(int) = ^(int n) {
if (n <= 1) return n;
return fib(n - 1) + fib(n - 2);
};
return fib; // no-crash when copying a self-referencing 'fib'
// expected-warning-re@-1 {{Address of stack-allocated block declared on line {{[0-9]+}} is captured by a returned block}}
}