[analyzer] Minor fixes and improvements to debug.ExprInspection

- Fix the bug with transition handling in ExprInspectionChecker's
  checkDeadSymbols implementation.

- Test this bug by adding a new function clang_analyzer_numTimesReached() to
  catch number of passes through the code, which should be handy for testing
  against unintended state splits.

- Add two more functions should help debugging issues quickly without running
  the debugger or dumping exploded graphs - clang_analyzer_dump() which dump()s
  an SVal argument to a warning message, and clang_analyzer_printState(), which
  dump()s the current program state to stderr.

Differential Revision: https://reviews.llvm.org/D26835

llvm-svn: 288257

1 files changed, 39 insertions, 0 deletions

diff --git a/clang/docs/analyzer/DebugChecks.rst b/clang/docs/analyzer/DebugChecks.rst
index bfa3142efbd..ecf11ca0f13 100644
--- a/clang/docs/analyzer/DebugChecks.rst
+++ b/clang/docs/analyzer/DebugChecks.rst
@@ -138,6 +138,17 @@ ExprInspection checks
       clang_analyzer_warnIfReached();  // no-warning
     }
 
+- void clang_analyzer_numTimesReached();
+
+  Same as above, but include the number of times this call expression
+  gets reached by the analyzer during the current analysis.
+
+  Example usage::
+
+    for (int x = 0; x < 3; ++x) {
+      clang_analyzer_numTimesReached(); // expected-warning{{3}}
+    }
+
 - void clang_analyzer_warnOnDeadSymbol(int);
 
   Subscribe for a delayed warning when the symbol that represents the value of
@@ -180,6 +191,18 @@ ExprInspection checks
         clang_analyzer_explain(ptr); // expected-warning{{memory address '0'}}
     }
 
+- void clang_analyzer_dump(a single argument of any type);
+
+  Similar to clang_analyzer_explain, but produces a raw dump of the value,
+  same as SVal::dump().
+
+  Example usage::
+
+    void clang_analyzer_dump(int);
+    void foo(int x) {
+      clang_analyzer_dump(x); // expected-warning{{reg_$0<x>}}
+    }
+
 - size_t clang_analyzer_getExtent(void *);
 
   This function returns the value that represents the extent of a memory region
@@ -197,6 +220,22 @@ ExprInspection checks
       clang_analyzer_explain(ys); // expected-warning{{'8'}}
     }
 
+- void clang_analyzer_printState();
+
+  Dumps the current ProgramState to the stderr. Quickly lookup the program state
+  at any execution point without ViewExplodedGraph or re-compiling the program.
+  This is not very useful for writing tests (apart from testing how ProgramState
+  gets printed), but useful for debugging tests. Also, this method doesn't
+  produce a warning, so it gets printed on the console before all other
+  ExprInspection warnings.
+
+  Example usage::
+
+    void foo() {
+      int x = 1;
+      clang_analyzer_printState(); // Read the stderr!
+    }
+
 Statistics
 ==========