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[analyzer] Add support for __builtin_constant_p. 

This builtin is evaluated in compile time. But in the analyzer we don't yet
automagically evaluate all calls that can be evaluated in compile time.

Patch by Felix Kostenzer!

Differential Revision: https://reviews.llvm.org/D42745

llvm-svn: 324789
This commit is contained in:
Artem Dergachev 2018-02-10 00:51:47 +00:00
parent 560b244c9b
commit f3e09bdaee
2 changed files with 19 additions and 1 deletions
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3
clang/lib/StaticAnalyzer/Checkers/BuiltinFunctionChecker.cpp
View File

@ -96,7 +96,8 @@ bool BuiltinFunctionChecker::evalCall(const CallExpr *CE,
return true;
}
case Builtin::BI__builtin_object_size: {
case Builtin::BI__builtin_object_size:
case Builtin::BI__builtin_constant_p: {
// This must be resolvable at compile time, so we defer to the constant
// evaluator for a value.
SVal V = UnknownVal();

17
clang/test/Analysis/builtin-functions.cpp
View File

@ -64,3 +64,20 @@ void g(int i) {
// We give up the analysis on this path.
}
}
void test_constant_p() {
int i = 1;
const int j = 2;
constexpr int k = 3;
clang_analyzer_eval(__builtin_constant_p(42) == 1); // expected-warning {{TRUE}}
clang_analyzer_eval(__builtin_constant_p(i) == 0); // expected-warning {{TRUE}}
clang_analyzer_eval(__builtin_constant_p(j) == 1); // expected-warning {{TRUE}}
clang_analyzer_eval(__builtin_constant_p(k) == 1); // expected-warning {{TRUE}}
clang_analyzer_eval(__builtin_constant_p(i + 42) == 0); // expected-warning {{TRUE}}
clang_analyzer_eval(__builtin_constant_p(j + 42) == 1); // expected-warning {{TRUE}}
clang_analyzer_eval(__builtin_constant_p(k + 42) == 1); // expected-warning {{TRUE}}
clang_analyzer_eval(__builtin_constant_p(" ") == 1); // expected-warning {{TRUE}}
clang_analyzer_eval(__builtin_constant_p(test_constant_p) == 0); // expected-warning {{TRUE}}
clang_analyzer_eval(__builtin_constant_p(k - 3) == 0); // expected-warning {{FALSE}}
clang_analyzer_eval(__builtin_constant_p(k - 3) == 1); // expected-warning {{TRUE}}
}