analyzer: rename region-model-impl-calls.cc to kf.cc

gcc/ChangeLog:
	* Makefile.in (ANALYZER_OBJS): Update for renaming of
	analyzer/region-model-impl-calls.cc to analyzer/kf.cc.

gcc/analyzer/ChangeLog:
	* analyzer.h (class known_function): Expand comment.
	* region-model-impl-calls.cc: Rename to...
	* kf.cc: ...this.
	* known-function-manager.h (class known_function_manager): Add
	leading comment.

Signed-off-by: David Malcolm <dmalcolm@redhat.com>

gcc/Makefile.in

@@ -1269,6 +1269,7 @@ ANALYZER_OBJS = \
 	analyzer/feasible-graph.o \
 	analyzer/function-set.o \
 	analyzer/infinite-recursion.o \
+	analyzer/kf.o \
 	analyzer/kf-analyzer.o \
 	analyzer/kf-lang-cp.o \
 	analyzer/known-function-manager.o \
@@ -1278,7 +1279,6 @@ ANALYZER_OBJS = \
 	analyzer/region.o \
 	analyzer/region-model.o \
 	analyzer/region-model-asm.o \
-	analyzer/region-model-impl-calls.o \
 	analyzer/region-model-manager.o \
 	analyzer/region-model-reachability.o \
 	analyzer/sm.o \

gcc/analyzer/analyzer.h

@@ -229,7 +229,8 @@ extern location_t get_stmt_location (const gimple *stmt, function *fun);
 extern bool compat_types_p (tree src_type, tree dst_type);
 
 /* Abstract base class for simulating the behavior of known functions,
-   supplied by the core of the analyzer, or by plugins.  */
+   supplied by the core of the analyzer, or by plugins.
+   The former are typically implemented in the various kf*.cc  */
 
 class known_function
 {

gcc/analyzer/known-function-manager.h

@@ -25,6 +25,18 @@ along with GCC; see the file COPYING3.  If not see
 
 namespace ana {
 
+/* Instances of known_function are registered with the known_function_manager
+   when the analyzer starts.
+
+   The known_function_manager has responsibility for determining which
+   known_function instance (if any) is relevant at a call site, by checking
+   name or id, and by calling known_function::matches_call_types_p to ensure
+   that the known_function's preconditions hold (typically assumptions about
+   types e.g. that "has 3 args, and that arg 0 is of pointer type").
+
+   The known_function subclasses themselves have responsibility for
+   determining the outcome(s) of the call.  */
+
 class known_function_manager : public log_user
 {
 public: