ASDenysPetrov added inline comments.
================
Comment at: clang/lib/StaticAnalyzer/Core/RegionStore.cpp:1669-1711
// The array index has to be known.
if (auto CI = R->getIndex().getAs<nonloc::ConcreteInt>()) {
- // If it is not an array, return Undef.
- QualType T = VD->getType();
- const ConstantArrayType *CAT = Ctx.getAsConstantArrayType(T);
- if (!CAT)
- return UndefinedVal();
-
- // Support one-dimensional array.
- // C++20 [expr.add] 7.6.6.4 (excerpt):
- // If P points to an array element i of an array object x with n
- // elements, where i < 0 or i > n, the behavior is undefined.
- // Dereferencing is not allowed on the "one past the last
- // element", when i == n.
- // Example:
- // const int arr[4] = {1, 2};
- // const int *ptr = arr;
- // int x0 = ptr[0]; // 1
- // int x1 = ptr[1]; // 2
- // int x2 = ptr[2]; // 0
- // int x3 = ptr[3]; // 0
- // int x4 = ptr[4]; // UB
- // TODO: Support multidimensional array.
- if (!isa<ConstantArrayType>(CAT->getElementType())) {
- // One-dimensional array.
- const llvm::APSInt &Idx = CI->getValue();
- const auto I = static_cast<uint64_t>(Idx.getExtValue());
- // Use `getZExtValue` because array extent can not be negative.
- const uint64_t Extent = CAT->getSize().getZExtValue();
- // Check for `Idx < 0`, NOT for `I < 0`, because `Idx` CAN be
- // negative, but `I` can NOT.
- if (Idx < 0 || I >= Extent)
- return UndefinedVal();
-
- // C++20 [expr.add] 9.4.17.5 (excerpt):
- // i-th array element is value-initialized for each k < i ≤ n,
- // where k is an expression-list size and n is an array extent.
- if (I >= InitList->getNumInits())
- return svalBuilder.makeZeroVal(R->getElementType());
-
- // Return a constant value, if it is presented.
- // FIXME: Support other SVals.
- const Expr *E = InitList->getInit(I);
- if (Optional<SVal> V = svalBuilder.getConstantVal(E))
- return *V;
+ // We treat only ConstantArrayType.
+ const QualType T = VD->getType();
+ if (const ConstantArrayType *CAT = Ctx.getAsConstantArrayType(T)) {
+ // Support one-dimensional array.
+ // C++20 [expr.add] 7.6.6.4 (excerpt):
----------------
martong wrote:
> Denys, I suppose we could replace the whole inner block with a function?
> Similarly to `getSValFromStringLiteralByIndex` from D107339 . That could
> greatly increase readability.
Make sense. I'll carry this block out.
================
Comment at: clang/test/Analysis/initialization.c:101-102
+
+const int glob_arr3[]; // Incomplete array declaration
+const int glob_arr3[4] = {1, 2, 3}; // Incomplete Array redeclaration
+void foo() {
----------------
steakhal wrote:
> ASDenysPetrov wrote:
> > martong wrote:
> > > I'd like to see some more elaborate test cases. Notably
> > > ```
> > > const int glob_arr3[]; // Incomplete array declaration
> > > const int glob_arr3[4] = {1, 2, 3}; // Incomplete Array redeclaration
> > > const int glob_arr3[]; // Incomplete array redeclaration
> > > ```
> > > here neither the canonical nor the most recent decl have the initexpr.
> > > And I think this is what @balazske tried to point out.
> > Exactly. I'll add this particular case, but I should mention that **AST**
> > surprisingly shows the third redeclaration as `ConstantArrayType` with the
> > extent. Thus, it works for the current fix.
> > ```
> > |-VarDecl 0xc0725b0 <line:6:1, col:21> col:11 glob_arr3 'const int []'
> > |-VarDecl 0xc072700 prev 0xc0725b0 <line:7:1, col:34> col:11 glob_arr3
> > 'const int [4]' cinit
> > | `-InitListExpr 0xc072830 <col:26, col:34> 'const int [4]'
> > | |-array_filler: ImplicitValueInitExpr 0xc0728a8 <<invalid sloc>> 'const
> > int'
> > | |-IntegerLiteral 0xc072768 <col:27> 'int' 1
> > | |-IntegerLiteral 0xc072788 <col:30> 'int' 2
> > | `-IntegerLiteral 0xc0727a8 <col:33> 'int' 3
> > `-VarDecl 0xc0728e0 prev 0xc072700 <line:8:1, col:21> col:11 glob_arr3
> > 'const int [4]'
> > ```
> So, the redeclaration actually changed the type to `ConstantArrayType`. If
> so, you should probably mention this in the comment.
OK, I'll mention.
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D111542/new/
https://reviews.llvm.org/D111542
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