r324789 - [analyzer] Add support for __builtin_constant_p.

[Artem Dergachev via cfe-commits]

Author: dergachev
Date: Fri Feb  9 16:51:47 2018
New Revision: 324789

URL: http://llvm.org/viewvc/llvm-project?rev=324789&view=rev
Log:
[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

Modified:
    cfe/trunk/lib/StaticAnalyzer/Checkers/BuiltinFunctionChecker.cpp
    cfe/trunk/test/Analysis/builtin-functions.cpp

Modified: cfe/trunk/lib/StaticAnalyzer/Checkers/BuiltinFunctionChecker.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/StaticAnalyzer/Checkers/BuiltinFunctionChecker.cpp?rev=324789&r1=324788&r2=324789&view=diff
==============================================================================
--- cfe/trunk/lib/StaticAnalyzer/Checkers/BuiltinFunctionChecker.cpp (original)
+++ cfe/trunk/lib/StaticAnalyzer/Checkers/BuiltinFunctionChecker.cpp Fri Feb  9 16:51:47 2018
@@ -96,7 +96,8 @@ bool BuiltinFunctionChecker::evalCall(co
     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();

Modified: cfe/trunk/test/Analysis/builtin-functions.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Analysis/builtin-functions.cpp?rev=324789&r1=324788&r2=324789&view=diff
==============================================================================
--- cfe/trunk/test/Analysis/builtin-functions.cpp (original)
+++ cfe/trunk/test/Analysis/builtin-functions.cpp Fri Feb  9 16:51:47 2018
@@ -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}}
+}