Skip to content

Commit

Permalink
[analyzer] Fix crash analyzing _BitInt() in evalIntegralCast
Browse files Browse the repository at this point in the history
evalIntegralCast was using makeIntVal, and when _BitInt() types were
introduced this exposed a crash in evalIntegralCast as a result.

Improve evalIntegralCast to use makeIntVal more efficiently to avoid the
crash exposed by use of _BitInt.

This was caught with our internal randomized testing.

<src-root>/llvm/include/llvm/ADT/APInt.h:1510:
  int64_t llvm::APInt::getSExtValue() const: Assertion
  `getSignificantBits() <= 64 && "Too many bits for int64_t"' failed.a

...
 #9 <address> llvm::APInt::getSExtValue() const
  <src-root>/llvm/include/llvm/ADT/APInt.h:1510:5
  llvm::IntrusiveRefCntPtr<clang::ento::ProgramState const>,
  clang::ento::SVal, clang::QualType, clang::QualType)
  <src-root>/clang/lib/StaticAnalyzer/Core/SValBuilder.cpp:607:24
  clang::Expr const*, clang::ento::ExplodedNode*, clang::ento::ExplodedNodeSet&)
  <src-root>/clang/lib/StaticAnalyzer/Core/ExprEngineC.cpp:413:61
...

 Fixes: #61960

 Reviewed By: donat.nagy
  • Loading branch information
vabridgers authored and einvbri committed Sep 18, 2023
1 parent 4b5366c commit ea63aae
Show file tree
Hide file tree
Showing 2 changed files with 14 additions and 5 deletions.
8 changes: 3 additions & 5 deletions clang/lib/StaticAnalyzer/Core/SValBuilder.cpp
Original file line number Diff line number Diff line change
Expand Up @@ -598,11 +598,9 @@ SVal SValBuilder::evalIntegralCast(ProgramStateRef state, SVal val,
APSIntType ToType(getContext().getTypeSize(castTy),
castTy->isUnsignedIntegerType());
llvm::APSInt ToTypeMax = ToType.getMaxValue();
NonLoc ToTypeMaxVal =
makeIntVal(ToTypeMax.isUnsigned() ? ToTypeMax.getZExtValue()
: ToTypeMax.getSExtValue(),
castTy)
.castAs<NonLoc>();

NonLoc ToTypeMaxVal = makeIntVal(ToTypeMax);

// Check the range of the symbol being casted against the maximum value of the
// target type.
NonLoc FromVal = val.castAs<NonLoc>();
Expand Down
11 changes: 11 additions & 0 deletions clang/test/Analysis/bitint-no-crash.c
Original file line number Diff line number Diff line change
@@ -0,0 +1,11 @@
// RUN: %clang_analyze_cc1 -analyzer-checker=core \
// RUN: -analyzer-checker=debug.ExprInspection \
// RUN: -verify %s

// Don't crash when using _BitInt()
// expected-no-diagnostics
_BitInt(256) a;
_BitInt(129) b;
void c() {
b = a;
}

0 comments on commit ea63aae

Please sign in to comment.