jit: implement gcc_jit_rvalue_set_bool_require_tail_call

This implements the libgccjit support for must-tail-call via
a new:
  gcc_jit_rvalue_set_bool_require_tail_call
API entrypoint.

(I didn't implement a wrapper for this within the C++ bindings)

gcc/jit/ChangeLog:
	* docs/topics/compatibility.rst: Add LIBGCCJIT_ABI_6.
	* docs/topics/expressions.rst (Function calls): Add documentation
	of gcc_jit_rvalue_set_bool_require_tail_call.
	* docs/_build/texinfo/libgccjit.texi: Regenerate.
	* jit-common.h (gcc::jit::recording::base_call): Add forward decl.
	* jit-playback.c: Within namespace gcc::jit::playback...
	(context::build_call) Add "require_tail_call" param and use it
	to set CALL_EXPR_MUST_TAIL_CALL.
	(context::new_call): Add "require_tail_call" param.
	(context::new_call_through_ptr): Likewise.
	* jit-playback.h: Within namespace gcc::jit::playback...
	(context::new_call: Add "require_tail_call" param.
	(context::new_call_through_ptr): Likewise.
	(context::build_call): Likewise.
	* jit-recording.c: Within namespace gcc::jit::recording...
	(base_call::base_call): New constructor.
	(base_call::write_reproducer_tail_call): New method.
	(call::call): Update for inheritance from base_call.
	(call::replay_into): Provide m_require_tail_call to call
	to new_call.
	(call::write_reproducer): Call write_reproducer_tail_call.
	(call_through_ptr::call_through_ptr): Update for inheritance from
	base_call.
	(call_through_ptr::replay_into): Provide m_require_tail_call to call
	to new_call_through_ptr.
	(recording::call_through_ptr::write_reproducer): Call
	write_reproducer_tail_call.
	* jit-recording.h: Within namespace gcc::jit::recording...
	(rvalue::dyn_cast_base_call): New virtual function.
	(class base_call): New subclass of class rvalue.
	(class call): Inherit from base_call rather than directly from
	rvalue, moving get_precedence and m_args to base_call.
	(class call_through_ptr): Likewise.
	* libgccjit.c (gcc_jit_rvalue_set_bool_require_tail_call): New
	function.
	* libgccjit.h
	(LIBGCCJIT_HAVE_gcc_jit_rvalue_set_bool_require_tail_call): New
	macro.
	(gcc_jit_rvalue_set_bool_require_tail_call): New function.
	* libgccjit.map (LIBGCCJIT_ABI_6): New.
	(gcc_jit_rvalue_set_bool_require_tail_call): Add.

gcc/testsuite/ChangeLog:
	* jit.dg/all-non-failing-tests.h: Add
	test-factorial-must-tail-call.c.
	* jit.dg/test-error-impossible-must-tail-call.c: New test case.
	* jit.dg/test-factorial-must-tail-call.c: New test case.

From-SVN: r236531

1 files changed, 33 insertions, 13 deletions

diff --git a/gcc/jit/jit-recording.h b/gcc/jit/jit-recording.h
index 1c3e763..0e3511c 100644
--- a/gcc/jit/jit-recording.h
+++ b/gcc/jit/jit-recording.h
@@ -960,8 +960,9 @@ public:
   void set_scope (function *scope);
   function *get_scope () const { return m_scope; }
 
-  /* Dynamic cast.  */
+  /* Dynamic casts.  */
   virtual param *dyn_cast_param () { return NULL; }
+  virtual base_call *dyn_cast_base_call () { return NULL; }
 
   virtual const char *access_as_rvalue (reproducer &r);
 
@@ -1418,7 +1419,36 @@ private:
   rvalue *m_rvalue;
 };
 
-class call : public rvalue
+class base_call : public rvalue
+{
+ public:
+  base_call (context *ctxt,
+	     location *loc,
+	     type *type_,
+	     int numargs,
+	     rvalue **args);
+
+  enum precedence get_precedence () const FINAL OVERRIDE
+  {
+    return PRECEDENCE_POSTFIX;
+  }
+
+  base_call *dyn_cast_base_call () FINAL OVERRIDE { return this; }
+
+  void set_require_tail_call (bool require_tail_call)
+  {
+    m_require_tail_call = require_tail_call;
+  }
+
+ protected:
+  void write_reproducer_tail_call (reproducer &r, const char *id);
+
+ protected:
+  auto_vec<rvalue *> m_args;
+  bool m_require_tail_call;
+};
+
+class call : public base_call
 {
 public:
   call (context *ctxt,
@@ -1434,17 +1464,12 @@ public:
 private:
   string * make_debug_string () FINAL OVERRIDE;
   void write_reproducer (reproducer &r) FINAL OVERRIDE;
-  enum precedence get_precedence () const FINAL OVERRIDE
-  {
-    return PRECEDENCE_POSTFIX;
-  }
 
 private:
   function *m_func;
-  auto_vec<rvalue *> m_args;
 };
 
-class call_through_ptr : public rvalue
+class call_through_ptr : public base_call
 {
 public:
   call_through_ptr (context *ctxt,
@@ -1460,14 +1485,9 @@ public:
 private:
   string * make_debug_string () FINAL OVERRIDE;
   void write_reproducer (reproducer &r) FINAL OVERRIDE;
-  enum precedence get_precedence () const FINAL OVERRIDE
-  {
-    return PRECEDENCE_POSTFIX;
-  }
 
 private:
   rvalue *m_fn_ptr;
-  auto_vec<rvalue *> m_args;
 };
 
 class array_access : public lvalue