vm: strip out call-counting profiler

This makes the separate "code" and "entry_point" fields in word and quotation redundant, so also remove them to reclaim an additional cell per word and quotation object, which should help with factor#318.

GNUmakefile

@@ -34,7 +34,6 @@ ifdef CONFIG
 		vm/code_heap.o \
 		vm/compaction.o \
 		vm/contexts.o \
-		vm/counting_profiler.o \
 		vm/data_heap.o \
 		vm/data_heap_checker.o \
 		vm/debug.o \
@@ -77,7 +76,6 @@ ifdef CONFIG
 		vm/contexts.hpp \
 		vm/run.hpp \
 		vm/objects.hpp \
-		vm/counting_profiler.hpp \
 		vm/sampling_profiler.hpp \
 		vm/errors.hpp \
 		vm/bignumint.hpp \

Nmakefile

@@ -37,7 +37,6 @@ DLL_OBJS = $(PLAF_DLL_OBJS) \
 	vm\code_heap.obj \
 	vm\compaction.obj \
 	vm\contexts.obj \
-	vm\counting_profiler.obj \
 	vm\data_heap.obj \
 	vm\data_heap_checker.obj \
 	vm\debug.obj \

basis/bootstrap/image/image.factor

@@ -350,11 +350,8 @@ M: f ' drop \ f type-number ;
                     [ props>> , ]
                     [ pic-def>> , ]
                     [ pic-tail-def>> , ]
-                    [ drop 0 , ] ! count
                     [ word-sub-primitive , ]
-                    [ drop 0 , ] ! xt
-                    [ drop 0 , ] ! code
-                    [ drop 0 , ] ! profiling
+                    [ drop 0 , ] ! entry point
                 } cleave
             ] { } make [ ' ] map
         ] bi
@@ -493,8 +490,7 @@ M: quotation '
             emit ! array
             f ' emit ! cached-effect
             f ' emit ! cache-counter
-            0 emit ! xt
-            0 emit ! code
+            0 emit ! entry point
         ] emit-object
     ] cache-eql-object ;
 

basis/compiler/constants/constants.factor

@@ -20,9 +20,9 @@ CONSTANT: deck-bits 18
 : alien-offset ( -- n ) 4 alien type-number slot-offset ; inline
 : underlying-alien-offset ( -- n ) 1 alien type-number slot-offset ; inline
 : tuple-class-offset ( -- n ) 1 tuple type-number slot-offset ; inline
-: word-entry-point-offset ( -- n ) 10 \ word type-number slot-offset ; inline
+: word-entry-point-offset ( -- n ) 9 \ word type-number slot-offset ; inline
 : quot-entry-point-offset ( -- n ) 4 quotation type-number slot-offset ; inline
-: word-code-offset ( -- n ) 11 \ word type-number slot-offset ; inline
+: code-block-entry-point-offset ( -- n ) 4 bootstrap-cells ; inline
 : array-start-offset ( -- n ) 2 array type-number slot-offset ; inline
 : compiled-header-size ( -- n ) 4 bootstrap-cells ; inline
 : callstack-length-offset ( -- n ) 1 \ callstack type-number slot-offset ; inline

basis/cpu/x86/bootstrap.factor

@@ -76,19 +76,6 @@ big-endian off
     HEX: ffff RET f rc-absolute-2 rel-untagged
 ] callback-stub jit-define
 
-[
-    ! Load word
-    temp0 0 MOV f rc-absolute-cell rel-literal
-    ! Bump profiling counter
-    temp0 profile-count-offset [+] 1 tag-fixnum ADD
-    ! Load word->code
-    temp0 temp0 word-code-offset [+] MOV
-    ! Compute word entry point
-    temp0 compiled-header-size ADD
-    ! Jump to entry point
-    temp0 JMP
-] jit-profiling jit-define
-
 [
     ! load literal
     temp0 0 MOV f rc-absolute-cell rel-literal

core/bootstrap/primitives.factor

@@ -241,7 +241,6 @@ bi
     "props"
     "pic-def"
     "pic-tail-def"
-    { "counter" { "fixnum" "math" } }
     { "sub-primitive" read-only }
 } define-builtin
 

vm/code_block_visitor.hpp

@@ -59,19 +59,15 @@ void code_block_visitor<Fixup>::visit_object_code_block(object *obj)
 	case WORD_TYPE:
 		{
 			word *w = (word *)obj;
-			if(w->code)
-				w->code = visit_code_block(w->code);
-			if(w->counting_profiler)
-				w->counting_profiler = visit_code_block(w->counting_profiler);
-
-			parent->update_word_entry_point(w);
+			if(w->entry_point)
+				w->entry_point = visit_code_block(w->code())->entry_point();
 			break;
 		}
 	case QUOTATION_TYPE:
 		{
 			quotation *q = (quotation *)obj;
-			if(q->code)
-				parent->set_quot_entry_point(q,visit_code_block(q->code));
+			if(q->entry_point)
+				q->entry_point = visit_code_block(q->code())->entry_point();
 			break;
 		}
 	case CALLSTACK_TYPE:

vm/code_blocks.hpp

@@ -84,4 +84,17 @@ struct code_block
 };
 
 VM_C_API void undefined_symbol(void);
+
+inline code_block *word::code() const {
+	assert(entry_point != NULL);
+	return (code_block*)entry_point - 1;
+}
+
+inline code_block *quotation::code() const {
+	assert(entry_point != NULL);
+	return (code_block*)entry_point - 1;
 }
+
+}
+
+

vm/code_heap.cpp

@@ -178,15 +178,13 @@ void factor_vm::primitive_modify_code_heap()
 					parameters,
 					literals);
 
-				word->code = compiled;
+				word->entry_point = compiled->entry_point();
 			}
 			break;
 		default:
 			critical_error("Expected a quotation or an array",data.value());
 			break;
 		}
-
-		update_word_entry_point(word.untagged());
 	}
 
 	if(update_existing_words)

vm/cpu-x86.cpp

@@ -63,7 +63,7 @@ void factor_vm::dispatch_signal_handler(cell *sp, cell *pc, cell handler)
 		else
 			assert(false);
 
-		*pc = (cell)handler_word->code->entry_point();
+		*pc = (cell)handler_word->entry_point;
 	}
 }
 

vm/entry_points.cpp

@@ -22,34 +22,30 @@ void factor_vm::c_to_factor(cell quot)
 
 template<typename Func> Func factor_vm::get_entry_point(cell n)
 {
-	/* We return word->code->entry_point() and not word->entry_point,
-	because if the counting profiler is enabled, we don't want to go through the
-	entry point's counting profiler stub. This clobbers registers, since entry
-	points use the C ABI and not the Factor ABI. */
 	tagged<word> entry_point_word(special_objects[n]);
-	return (Func)entry_point_word->code->entry_point();
+	return (Func)entry_point_word->entry_point;
 }
 
 void factor_vm::unwind_native_frames(cell quot, stack_frame *to)
 {
 	tagged<word> entry_point_word(special_objects[UNWIND_NATIVE_FRAMES_WORD]);
-	void *func = entry_point_word->code->entry_point();
+	void *func = entry_point_word->entry_point;
 	CODE_TO_FUNCTION_POINTER(func);
 	((unwind_native_frames_func_type)func)(quot,to);
 }
 
 cell factor_vm::get_fpu_state()
 {
 	tagged<word> entry_point_word(special_objects[GET_FPU_STATE_WORD]);
-	void *func = entry_point_word->code->entry_point();
+	void *func = entry_point_word->entry_point;
 	CODE_TO_FUNCTION_POINTER(func);
 	return ((get_fpu_state_func_type)func)();
 }
 
 void factor_vm::set_fpu_state(cell state)
 {
 	tagged<word> entry_point_word(special_objects[SET_FPU_STATE_WORD]);
-	void *func = entry_point_word->code->entry_point();
+	void *func = entry_point_word->entry_point;
 	CODE_TO_FUNCTION_POINTER(func);
 	((set_fpu_state_func_type)func)(state);
 }

vm/jit.cpp

@@ -4,7 +4,6 @@ namespace factor
 {
 
 /* Simple code generator used by:
-- counting_profiler (counting_profiler.cpp),
 - quotation compiler (quotations.cpp),
 - megamorphic caches (dispatch.cpp),
 - polymorphic inline caches (inline_cache.cpp) */

vm/layouts.hpp

@@ -98,7 +98,6 @@ enum code_block_type
 {
 	code_block_unoptimized,
 	code_block_optimized,
-	code_block_counting_profiler,
 	code_block_pic
 };
 
@@ -253,7 +252,11 @@ struct string : public object {
 
 struct code_block;
 
-/* Assembly code makes assumptions about the layout of this struct */
+/* Assembly code makes assumptions about the layout of this struct:
+	basis/bootstrap/images/images.factor
+	basis/compiler/constants/constants.factor
+	core/bootstrap/primitives.factor
+*/
 struct word : public object {
 	static const cell type_number = WORD_TYPE;
 	/* TAGGED hashcode */
@@ -270,16 +273,14 @@ struct word : public object {
 	cell pic_def;
 	/* TAGGED alternative entry point for direct tail calls. Used for inline caching */
 	cell pic_tail_def;
-	/* TAGGED call count for counting_profiler */
-	cell counter;
 	/* TAGGED machine code for sub-primitive */
 	cell subprimitive;
 	/* UNTAGGED entry point: jump here to execute word */
 	void *entry_point;
 	/* UNTAGGED compiled code block */
-	code_block *code;
-	/* UNTAGGED counting_profiler stub */
-	code_block *counting_profiler;
+
+	/* defined in code_blocks.hpp */
+	code_block *code() const;
 };
 
 /* Assembly code makes assumptions about the layout of this struct */
@@ -299,7 +300,11 @@ struct boxed_float : object {
 	double n;
 };
 
-/* Assembly code makes assumptions about the layout of this struct */
+/* Assembly code makes assumptions about the layout of this struct:
+	basis/bootstrap/images/images.factor
+	basis/compiler/constants/constants.factor
+	core/bootstrap/primitives.factor
+*/
 struct quotation : public object {
 	static const cell type_number = QUOTATION_TYPE;
 	/* tagged */
@@ -310,8 +315,9 @@ struct quotation : public object {
 	cell cache_counter;
 	/* UNTAGGED entry point; jump here to call quotation */
 	void *entry_point;
-	/* UNTAGGED compiled code block */
-	code_block *code;
+
+	/* defined in code_blocks.hpp */
+	code_block *code() const;
 };
 
 /* Assembly code makes assumptions about the layout of this struct */

vm/master.hpp

@@ -96,7 +96,6 @@ namespace factor
 #include "contexts.hpp"
 #include "run.hpp"
 #include "objects.hpp"
-#include "counting_profiler.hpp"
 #include "sampling_profiler.hpp"
 #include "errors.hpp"
 #include "bignumint.hpp"

vm/primitives.hpp

@@ -46,7 +46,6 @@ namespace factor
 	_(context_object) \
 	_(context_object_for) \
 	_(current_callback) \
-	_(counting_profiler) \
 	_(data_room) \
 	_(datastack) \
 	_(datastack_for) \