[analyzer] Add StdLibraryFunctions checker.

This checker does not emit reports, however it influences the analysis
by providing complete summaries for, or otherwise improving modeling of,
various standard library functions.

This should reduce the number of infeasible paths explored during analysis.
The custom function summary format used in this checker is superior to
body farms by causing less unnecessary state splits,
which would result in better analysis performance.

Differential Revision: https://reviews.llvm.org/D20811

llvm-svn: 284960

1 files changed, 14 insertions, 0 deletions

diff --git a/clang/test/Analysis/std-c-library-functions.cpp b/clang/test/Analysis/std-c-library-functions.cpp
new file mode 100644
index 00000000000..271fffde692
--- /dev/null
+++ b/clang/test/Analysis/std-c-library-functions.cpp
@@ -0,0 +1,14 @@
+// RUN: %clang_cc1 -analyze -analyzer-checker=unix.StdCLibraryFunctions,debug.ExprInspection -verify %s
+
+// Test that we don't model functions with broken prototypes.
+// Because they probably work differently as well.
+//
+// This test lives in a separate file because we wanted to test all functions
+// in the .c file, however in C there are no overloads.
+
+void clang_analyzer_eval(bool);
+bool isalpha(char);
+
+void test() {
+  clang_analyzer_eval(isalpha('A')); // no-crash // expected-warning{{UNKNOWN}}
+}