[clang] da26500 - [analyzer] Fix crash analyzing _BitInt() in evalIntegralCast (#66782)

[via cfe-commits]

Author: vabridgers
Date: 2023-09-20T06:11:39-05:00
New Revision: da26500aa82316f607ddc60e56982775d7f45cff

URL: https://github.com/llvm/llvm-project/commit/da26500aa82316f607ddc60e56982775d7f45cff
DIFF: https://github.com/llvm/llvm-project/commit/da26500aa82316f607ddc60e56982775d7f45cff.diff

LOG: [analyzer] Fix crash analyzing _BitInt() in evalIntegralCast (#66782)

evalIntegralCast was using makeIntVal, and when _BitInt() types were
introduced this exposed a crash in evalIntegralCast as a result.

This is a reapply of a previous patch that failed post merge on the arm
buildbots, because arm cannot handle large
BitInts. Pinning the triple for the testcase solves that problem. 

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: https://github.com/llvm/llvm-project/issues/61960

 Reviewed By: donat.nagy

Added: 
    clang/test/Analysis/bitint-no-crash.c

Modified: 
    clang/lib/StaticAnalyzer/Core/SValBuilder.cpp

Removed: 
    


################################################################################
diff  --git a/clang/lib/StaticAnalyzer/Core/SValBuilder.cpp b/clang/lib/StaticAnalyzer/Core/SValBuilder.cpp
index 4fe828bdf7681fc..f827f43eaa7da67 100644
--- a/clang/lib/StaticAnalyzer/Core/SValBuilder.cpp
+++ b/clang/lib/StaticAnalyzer/Core/SValBuilder.cpp
@@ -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>();

diff  --git a/clang/test/Analysis/bitint-no-crash.c b/clang/test/Analysis/bitint-no-crash.c
new file mode 100644
index 000000000000000..0a367fa930dc9b1
--- /dev/null
+++ b/clang/test/Analysis/bitint-no-crash.c
@@ -0,0 +1,13 @@
+ // RUN: %clang_analyze_cc1 -analyzer-checker=core \
+ // RUN:   -analyzer-checker=debug.ExprInspection \
+ // RUN:   -triple x86_64-pc-linux-gnu \
+ // RUN:   -verify %s
+
+// Don't crash when using _BitInt(). Pin to the x86_64 triple for now,
+// since not all architectures support _BitInt()
+// expected-no-diagnostics
+_BitInt(256) a;
+_BitInt(129) b;
+void c() {
+  b = a;
+}