[analyzer] Add a testing facility for testing relationships between symbols.

Tests introduced in r329780 was disabled in r342317 because these tests
were accidentally testing dump infrastructure, when all they cared about was
how symbols relate to each other. So when dump infrastructure changed,
tests became annoying to maintain.

Add a new feature to ExprInspection: clang_analyzer_denote() and
clang_analyzer_explain(). The former adds a notation to a symbol, the latter
expresses another symbol in terms of previously denoted symbols.

It's currently a bit wonky - doesn't print parentheses and only supports
denoting atomic symbols. But it's even more readable that way.

Differential Revision: https://reviews.llvm.org/D52133

llvm-svn: 343048

1 files changed, 17 insertions, 0 deletions

diff --git a/clang/docs/analyzer/DebugChecks.rst b/clang/docs/analyzer/DebugChecks.rst
index 67521b82cabc..7b192f65224f 100644
--- a/clang/docs/analyzer/DebugChecks.rst
+++ b/clang/docs/analyzer/DebugChecks.rst
@@ -255,6 +255,23 @@ ExprInspection checks
       clang_analyzer_hashDump(x); // expected-warning{{hashed string for x}}
     }
 
+- ``void clang_analyzer_denote(int, const char *);``
+
+  Denotes symbols with strings. A subsequent call to clang_analyzer_express()
+  will expresses another symbol in terms of these string. Useful for testing
+  relationships between different symbols.
+
+  Example usage::
+
+    void foo(int x) {
+      clang_analyzer_denote(x, "$x");
+      clang_analyzer_express(x + 1); // expected-warning{{$x + 1}}
+    }
+
+- ``void clang_analyzer_express(int);``
+
+  See clang_analyzer_denote().
+
 Statistics
 ==========