finally proper stack unwind in the evaluator

4 files changed, 153 insertions, 196 deletions

diff --git a/src/runtime/c/pgf/data.h b/src/runtime/c/pgf/data.h
index 8e2b726a7..2b11f24da 100644
--- a/src/runtime/c/pgf/data.h
+++ b/src/runtime/c/pgf/data.h
@@ -136,8 +136,9 @@ typedef enum {
   PGF_INSTR_PUSH        =  9,
   PGF_INSTR_EVAL        = 10,
   PGF_INSTR_DROP        = 13,
-  PGF_INSTR_FAIL        = 14,
-  PGF_INSTR_ADD         = 15
+  PGF_INSTR_JUMP        = 14,
+  PGF_INSTR_FAIL        = 15,
+  PGF_INSTR_ADD         = 16
 } PgfInstruction;
 
 typedef GuSeq PgfConcrs;
diff --git a/src/runtime/c/pgf/evaluator.c b/src/runtime/c/pgf/evaluator.c
index bc89026fc..62fe0bdd5 100644
--- a/src/runtime/c/pgf/evaluator.c
+++ b/src/runtime/c/pgf/evaluator.c
@@ -5,6 +5,23 @@
 
 #define PGF_ARGS_DELTA 5
 
+static inline PgfClosure*
+pgf_mk_pap(PgfEvalState* state, PgfClosure* fun,
+           size_t n_args, PgfClosure** args)
+{
+	if (n_args > 0) {
+		PgfValuePAP* val = gu_new_flex(state->pool, PgfValuePAP, args, n_args);
+		val->header.code = state->eval_gates->evaluate_value_pap;
+		val->fun         = fun;
+		val->n_args      = n_args*sizeof(PgfClosure*);
+		for (size_t i = 0; i < n_args; i++) {
+			val->args[i] = args[i];
+		}
+		return &val->header;
+	}
+	return fun;
+}
+
 PgfClosure*
 pgf_evaluate_expr_thunk(PgfEvalState* state, PgfExprThunk* thunk)
 {
@@ -64,15 +81,11 @@ repeat:;
 		PgfExprMeta* emeta = ei.data;
 
 		PgfValueMeta* val =
-			gu_new_flex(state->pool, PgfValueMeta, args, n_args);
-		val->header.code = state->eval_gates->evaluate_value_meta;
-		val->id = emeta->id;
-		val->n_args = n_args*sizeof(PgfClosure*);
-		for (size_t i = 0; i < n_args; i++) {
-			val->args[i] = args[n_args-i-1];
-		}
-
-		res = &val->header;
+			gu_new(PgfValueMeta, state->pool);
+		val->header.code = state->eval_gates->evaluate_meta;
+		val->env = env;
+		val->id  = emeta->id;
+		res = pgf_mk_pap(state, &val->header, n_args, args);
 		break;
 	}
 	case PGF_EXPR_FUN: {
@@ -83,18 +96,7 @@ repeat:;
 		gu_assert(absfun != NULL);
 
 		if (absfun->closure.code != NULL) {
-			res = (PgfClosure*) &absfun->closure;
-
-			if (n_args > 0) {
-				PgfValuePAP* val = gu_new_flex(state->pool, PgfValuePAP, args, n_args);
-				val->header.code = state->eval_gates->evaluate_value_pap;
-				val->fun         = res;
-				val->n_args      = n_args*sizeof(PgfClosure*);
-				for (size_t i = 0; i < n_args; i++) {
-					val->args[i] = args[i];
-				}
-				res = &val->header;
-			}
+			res = pgf_mk_pap(state, (PgfClosure*) &absfun->closure, n_args, args);
 		} else {
 			size_t arity = absfun->arity;
 
@@ -113,18 +115,7 @@ repeat:;
 				PgfExprThunk* lambda = gu_new(PgfExprThunk, state->pool);
 				lambda->header.code = state->eval_gates->evaluate_value_lambda;
 				lambda->env = NULL;
-				res = &lambda->header;
-
-				if (n_args > 0) {
-					PgfValuePAP* val = gu_new_flex(state->pool, PgfValuePAP, args, n_args);
-					val->header.code = state->eval_gates->evaluate_value_pap;
-					val->fun = &lambda->header;
-					val->n_args = n_args*sizeof(PgfClosure*);
-					for (size_t i = 0; i < n_args; i++) {
-						val->args[i] = args[i];
-					}
-					res = &val->header;
-				}
+				res = pgf_mk_pap(state, &lambda->header, n_args, args);
 
 				for (size_t i = 0; i < arity; i++) {
 					PgfExpr new_expr, arg;
@@ -180,18 +171,7 @@ repeat:;
 			i--;
 		}
 
-		res = tmp_env->closure;
-
-		if (n_args > 0) {
-			PgfValuePAP* val = gu_new_flex(state->pool, PgfValuePAP, args, n_args);
-			val->header.code = state->eval_gates->evaluate_value_pap;
-			val->fun         = res;
-			val->n_args      = n_args*sizeof(PgfClosure*);
-			for (size_t i = 0; i < n_args; i++) {
-				val->args[i] = args[i];
-			}
-			res = &val->header;
-		}
+		res = pgf_mk_pap(state, tmp_env->closure, n_args, args);
 		break;
 	}
 	case PGF_EXPR_TYPED: {
@@ -245,28 +225,6 @@ pgf_value2expr(PgfEvalState* state, int level, PgfClosure* clos, GuPool* pool)
 		expr   = absfun->ep.expr;
 		n_args = absfun->arity;
 		args   = val->args;
-	} else if (clos->code == state->eval_gates->evaluate_value_gen) {
-		PgfValueGen* val = (PgfValueGen*) clos;
-
-		PgfExprVar *evar =
-			gu_new_variant(PGF_EXPR_VAR,
-						   PgfExprVar,
-						   &expr, pool);
-		evar->var = level - val->level - 1;
-
-		n_args = val->n_args/sizeof(PgfClosure*);
-		args   = val->args;
-	} else if (clos->code == state->eval_gates->evaluate_value_meta) {
-		PgfValueMeta* val = (PgfValueMeta*) clos;
-
-		PgfExprMeta *emeta =
-			gu_new_variant(PGF_EXPR_META,
-						   PgfExprMeta,
-						   &expr, pool);
-		emeta->id = val->id;
-
-		n_args = val->n_args / sizeof(PgfClosure*);
-		args   = val->args;
 	} else if (clos->code == state->eval_gates->evaluate_value_lit) {
 		PgfValueLit* val = (PgfValueLit*) clos;
 
@@ -316,18 +274,18 @@ pgf_value2expr(PgfEvalState* state, int level, PgfClosure* clos, GuPool* pool)
 
 		PgfValueGen* gen =
 			gu_new(PgfValueGen, state->pool);
-		gen->header.code = state->eval_gates->evaluate_value_gen;
+		gen->header.code = state->eval_gates->evaluate_gen;
 		gen->level  = level;
-		gen->n_args = 0;
 
-		PgfValuePAP* new_pap = gu_new_flex(state->pool, PgfValuePAP, args, pap->n_args+1);
+		size_t n_args = pap->n_args/sizeof(PgfClosure*);
+		PgfValuePAP* new_pap = gu_new_flex(state->pool, PgfValuePAP, args, n_args+1);
 		new_pap->header.code = state->eval_gates->evaluate_value_pap;
 		new_pap->fun         = pap->fun;
 		new_pap->n_args      = pap->n_args+sizeof(PgfClosure*);
-		for (size_t i = 0; i < pap->n_args/sizeof(PgfClosure*); i++) {
-			new_pap->args[i] = pap->args[i];
+		new_pap->args[0]     = &gen->header;
+		for (size_t i = 0; i < n_args; i++) {
+			new_pap->args[i+1] = pap->args[i];
 		}
-		new_pap->args[pap->n_args] = &gen->header;
 
 		PgfExprAbs *eabs =
 			gu_new_variant(PGF_EXPR_ABS,
@@ -336,6 +294,32 @@ pgf_value2expr(PgfEvalState* state, int level, PgfClosure* clos, GuPool* pool)
 		eabs->bind_type = PGF_BIND_TYPE_EXPLICIT;
 		eabs->id = gu_format_string(pool, "v%d", level);
 		eabs->body = pgf_value2expr(state, level+1, &new_pap->header, pool);
+	} else if (clos->code == state->eval_gates->evaluate_value_const) {
+		PgfValuePAP* val = (PgfValuePAP*) clos;
+		
+		if (val->fun->code == state->eval_gates->evaluate_meta) {
+			PgfValueMeta* fun = (PgfValueMeta*) val->fun;
+
+			PgfExprMeta *emeta =
+				gu_new_variant(PGF_EXPR_META,
+				               PgfExprMeta,
+				               &expr, pool);
+			emeta->id = fun->id;
+		} else if (val->fun->code == state->eval_gates->evaluate_gen) {
+			PgfValueGen* fun = (PgfValueGen*) val->fun;
+
+			PgfExprVar *evar =
+				gu_new_variant(PGF_EXPR_VAR,
+				               PgfExprVar,
+				               &expr, pool);
+			evar->var = level - fun->level - 1;
+		} else {
+			PgfAbsFun* absfun = gu_container(val->fun, PgfAbsFun, closure);
+			expr   = absfun->ep.expr;
+		}
+
+		n_args = val->n_args/sizeof(PgfClosure*);
+		args   = val->args;
 	} else {
 		gu_impossible();
 	}
diff --git a/src/runtime/c/pgf/evaluator.h b/src/runtime/c/pgf/evaluator.h
index 09b0afb2a..1f56d61a9 100644
--- a/src/runtime/c/pgf/evaluator.h
+++ b/src/runtime/c/pgf/evaluator.h
@@ -40,16 +40,12 @@ typedef struct {
 typedef struct {
 	PgfClosure header;
 	int level;
-	size_t n_args;
-	PgfClosure* args[];
 } PgfValueGen;
 
 typedef struct {
 	PgfClosure header;
 	PgfEnv*  env;
 	PgfMetaId id;
-	size_t n_args;
-	PgfClosure* args[];
 } PgfValueMeta;
 
 typedef struct {
@@ -68,11 +64,12 @@ struct PgfEvalGates {
 	PgfFunction evaluate_expr_thunk;
 	PgfFunction evaluate_indirection;
 	PgfFunction evaluate_value;
-	PgfFunction evaluate_value_gen;
-	PgfFunction evaluate_value_meta;
 	PgfFunction evaluate_value_lit;
 	PgfFunction evaluate_value_pap;
 	PgfFunction evaluate_value_lambda;
+	PgfFunction evaluate_value_const;
+	PgfFunction evaluate_meta;
+	PgfFunction evaluate_gen;
 	PgfFunction evaluate_caf;
 
 	PgfFunction update_closure;
diff --git a/src/runtime/c/pgf/jit.c b/src/runtime/c/pgf/jit.c
index 8cb2257d6..0b42cc91f 100644
--- a/src/runtime/c/pgf/jit.c
+++ b/src/runtime/c/pgf/jit.c
@@ -329,8 +329,7 @@ PgfEvalGates*
 pgf_jit_gates(PgfReader* rdr)
 {
 	PgfEvalGates* gates = gu_new(PgfEvalGates, rdr->opool);
-	jit_insn* next;
-	jit_insn* ref, *ref2;
+	jit_insn *ref, *next, *ref2;
 
 	pgf_jit_make_space(rdr, JIT_CODE_WINDOW);
 
@@ -346,102 +345,6 @@ pgf_jit_gates(PgfReader* rdr)
 	jit_ldxi_p(JIT_RET, JIT_VHEAP, offsetof(PgfValue, con));
 	jit_bare_ret();
 
-	pgf_jit_make_space(rdr, JIT_CODE_WINDOW*2);
-
-	gates->evaluate_value_gen = jit_get_ip().ptr;
-	jit_subr_p(JIT_R0, JIT_FP, JIT_SP);
-	jit_subi_p(JIT_R0, JIT_R0, sizeof(void*));
-	ref = jit_bnei_i(jit_forward(), JIT_R0, 0);
-	jit_movr_p(JIT_VHEAP, JIT_VCLOS);
-	jit_bare_ret();
-	jit_patch(ref);
-	jit_pushr_i(JIT_R0);
-	jit_prepare(2);
-	jit_addi_i(JIT_R0, JIT_R0, sizeof(PgfValueGen));
-	jit_pusharg_ui(JIT_R0);
-	jit_ldxi_p(JIT_R0, JIT_VSTATE, offsetof(PgfEvalState,pool));
-	jit_pusharg_p(JIT_R0);
-	jit_finish(gu_malloc);
-	jit_retval(JIT_VHEAP);
-	jit_popr_i(JIT_R0);
-	jit_movi_p(JIT_R1, gates->evaluate_value_gen);
-	jit_str_p(JIT_VHEAP, JIT_R1);
-	jit_ldxi_p(JIT_R1, JIT_VCLOS, offsetof(PgfValueGen,level));
-	jit_stxi_p(offsetof(PgfValueGen,level), JIT_VHEAP, JIT_R1);
-	jit_ldxi_p(JIT_R1, JIT_VCLOS, offsetof(PgfValueGen,n_args));
-	jit_addr_i(JIT_R1, JIT_R1, JIT_R0);
-	jit_stxi_p(offsetof(PgfValueGen,n_args), JIT_VHEAP, JIT_R1);
-	jit_movi_i(JIT_R1, offsetof(PgfValueGen,args));
-	jit_ldxi_i(JIT_R2, JIT_VCLOS, offsetof(PgfValueGen,n_args));
-	jit_addr_i(JIT_R2, JIT_R2, JIT_R1);
-	jit_pushr_i(JIT_R0);
-	next = jit_get_label();
-	ref  = jit_bger_i(jit_forward(), JIT_R1, JIT_R2);
-	jit_ldxr_i(JIT_R0, JIT_VCLOS, JIT_R1);
-	jit_stxr_p(JIT_R1, JIT_VHEAP, JIT_R0);	
-	jit_addi_i(JIT_R1, JIT_R1, sizeof(void*));
-	jit_jmpi(next);
-	jit_patch(ref);
-	jit_popr_i(JIT_R0);
-	jit_addr_i(JIT_R2, JIT_R2, JIT_R0);
-	jit_popr_p(JIT_VCLOS);
-	next = jit_get_label();
-	ref  = jit_bger_i(jit_forward(), JIT_R1, JIT_R2);
-	jit_popr_p(JIT_R0);
-	jit_stxr_p(JIT_R1, JIT_VHEAP, JIT_R0);	
-	jit_addi_i(JIT_R1, JIT_R1, sizeof(void*));
-	jit_jmpi(next);
-	jit_patch(ref);
-	jit_jmpr(JIT_VCLOS);
-
-	pgf_jit_make_space(rdr, JIT_CODE_WINDOW*2);
-
-	gates->evaluate_value_meta = jit_get_ip().ptr;
-	jit_subr_p(JIT_R0, JIT_FP, JIT_SP);
-	jit_subi_p(JIT_R0, JIT_R0, sizeof(void*));
-	ref = jit_bnei_i(jit_forward(), JIT_R0, 0);
-	jit_movr_p(JIT_VHEAP, JIT_VCLOS);
-	jit_bare_ret();
-	jit_patch(ref);
-	jit_pushr_i(JIT_R0);
-	jit_prepare(2);
-	jit_addi_i(JIT_R0, JIT_R0, sizeof(PgfValueMeta));
-	jit_pusharg_ui(JIT_R0);
-	jit_ldxi_p(JIT_R0, JIT_VSTATE, offsetof(PgfEvalState,pool));
-	jit_pusharg_p(JIT_R0);
-	jit_finish(gu_malloc);
-	jit_retval(JIT_VHEAP);
-	jit_popr_i(JIT_R0);
-	jit_movi_p(JIT_R1, gates->evaluate_value_meta);
-	jit_str_p(JIT_VHEAP, JIT_R1);
-	jit_ldxi_p(JIT_R1, JIT_VCLOS, offsetof(PgfValueMeta,id));
-	jit_stxi_p(offsetof(PgfValueMeta,id), JIT_VHEAP, JIT_R1);
-	jit_ldxi_p(JIT_R1, JIT_VCLOS, offsetof(PgfValueMeta,n_args));
-	jit_addr_i(JIT_R1, JIT_R1, JIT_R0);
-	jit_stxi_p(offsetof(PgfValueMeta,n_args), JIT_VHEAP, JIT_R1);
-	jit_movi_i(JIT_R1, offsetof(PgfValueMeta,args));
-	jit_ldxi_i(JIT_R2, JIT_VCLOS, offsetof(PgfValueMeta,n_args));
-	jit_addr_i(JIT_R2, JIT_R2, JIT_R1);
-	jit_pushr_i(JIT_R0);
-	next = jit_get_label();
-	ref  = jit_bger_i(jit_forward(), JIT_R1, JIT_R2);
-	jit_ldxr_i(JIT_R0, JIT_VCLOS, JIT_R1);
-	jit_stxr_p(JIT_R1, JIT_VHEAP, JIT_R0);	
-	jit_addi_i(JIT_R1, JIT_R1, sizeof(PgfClosure*));
-	jit_jmpi(next);
-	jit_patch(ref);
-	jit_popr_i(JIT_R0);
-	jit_addr_i(JIT_R2, JIT_R2, JIT_R0);
-	jit_popr_p(JIT_VCLOS);
-	next = jit_get_label();
-	ref  = jit_bger_i(jit_forward(), JIT_R1, JIT_R2);
-	jit_popr_p(JIT_R0);
-	jit_stxr_p(JIT_R1, JIT_VHEAP, JIT_R0);	
-	jit_addi_i(JIT_R1, JIT_R1, sizeof(PgfClosure*));
-	jit_jmpi(next);
-	jit_patch(ref);
-	jit_jmpr(JIT_VCLOS);
-
 	pgf_jit_make_space(rdr, JIT_CODE_WINDOW);
 
 	gates->evaluate_value_lit = jit_get_ip().ptr;
@@ -470,6 +373,7 @@ pgf_jit_gates(PgfReader* rdr)
 	jit_getarg_p(JIT_VCLOS,  closure_arg);
 	jit_ldr_p(JIT_R0, JIT_VCLOS);
 	jit_callr(JIT_R0);
+	jit_insn* enter_ret = (void*) jit_get_ip().ptr;
 	jit_movr_p(JIT_RET, JIT_VHEAP);
 	jit_ret();
 
@@ -571,6 +475,7 @@ pgf_jit_gates(PgfReader* rdr)
 	ref = jit_beqr_p(jit_forward(), JIT_VCLOS, JIT_RET);
 	jit_pushr_p(JIT_VCLOS);
 	jit_pushr_p(JIT_FP);
+	jit_movr_p(JIT_FP, JIT_SP);
 	jit_movi_p(JIT_R1, gates->update_closure);
 	jit_pushr_p(JIT_R1);
 	jit_retval(JIT_VCLOS);
@@ -595,31 +500,96 @@ pgf_jit_gates(PgfReader* rdr)
 	jit_ldr_p(JIT_R0, JIT_VCLOS);
 	jit_jmpr(JIT_R0);
 
+	pgf_jit_make_space(rdr, JIT_CODE_WINDOW*2);
+
+	gates->evaluate_value_const = jit_get_ip().ptr;
+	jit_jmpi(gates->evaluate_value);
+
+	pgf_jit_make_space(rdr, JIT_CODE_WINDOW*2);
+
 	gates->mk_const = jit_get_ip().ptr;
-	jit_ldxi_p(JIT_R0, JIT_VCLOS, offsetof(PgfAbsFun,arity)-offsetof(PgfAbsFun,closure));
-	jit_muli_i(JIT_R0, JIT_R0, sizeof(PgfClosure*));
+	jit_popr_p(JIT_R0);
+	ref2 = jit_bnei_i(jit_forward(), JIT_R0, (int)gates->update_closure);
+	jit_subr_p(JIT_R0, JIT_FP, JIT_SP);
 	jit_pushr_i(JIT_R0);
 	jit_prepare(2);
-	jit_addi_i(JIT_R0, JIT_R0, sizeof(PgfValue));
+	jit_addi_i(JIT_R0, JIT_R0, sizeof(PgfValuePAP));
 	jit_pusharg_ui(JIT_R0);
 	jit_ldxi_p(JIT_R0, JIT_VSTATE, offsetof(PgfEvalState,pool));
 	jit_pusharg_p(JIT_R0);
 	jit_finish(gu_malloc);
-	jit_movi_p(JIT_R1, gates->evaluate_value);
-	jit_str_p(JIT_RET, JIT_R1);
-	jit_stxi_p(offsetof(PgfValue,con), JIT_RET, JIT_VCLOS);
-	jit_movr_p(JIT_VHEAP, JIT_RET);
 	jit_popr_i(JIT_R1);
-	jit_popr_p(JIT_VCLOS);
+	jit_movi_p(JIT_R2, gates->evaluate_value_const);
+	jit_str_p(JIT_RET, JIT_R2);
+	jit_stxi_p(offsetof(PgfValuePAP,fun), JIT_RET, JIT_VCLOS);
+	jit_stxi_p(offsetof(PgfValuePAP,n_args), JIT_RET, JIT_R1);
+	jit_ldxi_p(JIT_VHEAP, JIT_FP, sizeof(void*));
+	jit_movi_p(JIT_R2, gates->evaluate_indirection);
+	jit_str_p(JIT_VHEAP, JIT_R2);
+	jit_stxi_p(offsetof(PgfIndirection, val), JIT_VHEAP, JIT_RET);
+	jit_ldr_p(JIT_R2, JIT_FP);
+	jit_pushr_p(JIT_R2);
+	jit_ldxi_p(JIT_R2, JIT_FP, 2*sizeof(void*));
+	jit_pushr_p(JIT_R2);
+	jit_addi_p(JIT_RET, JIT_RET, offsetof(PgfValuePAP,args)-sizeof(PgfClosure*));
+	next = jit_get_label();
+	ref  = jit_blei_i(jit_forward(), JIT_R1, 0);
+	jit_ldxi_p(JIT_R2, JIT_FP, -sizeof(void*));
+	jit_stxi_p(2*sizeof(void*), JIT_FP, JIT_R2);
+	jit_stxr_p(JIT_R1, JIT_RET, JIT_R2);
+	jit_subi_i(JIT_FP, JIT_FP, sizeof(void*));
+	jit_subi_i(JIT_R1, JIT_R1, sizeof(void*));
+	jit_jmpi(next);
+	jit_patch(ref);
+	jit_popr_p(JIT_R0);
+	jit_popr_p(JIT_FP);
+	jit_addi_p(JIT_SP, JIT_SP, 3*sizeof(void*));
+	jit_pushr_p(JIT_R0);
+	jit_jmpi(gates->mk_const);
+	jit_patch(ref2);
+	ref2 = jit_bnei_i(jit_forward(), JIT_R0, (int)enter_ret);
+	jit_subr_p(JIT_R0, JIT_FP, JIT_SP);
+	jit_pushr_i(JIT_R0);
+	jit_prepare(2);
+	jit_addi_i(JIT_R0, JIT_R0, sizeof(PgfValuePAP));
+	jit_pusharg_ui(JIT_R0);
+	jit_ldxi_p(JIT_R0, JIT_VSTATE, offsetof(PgfEvalState,pool));
+	jit_pusharg_p(JIT_R0);
+	jit_finish(gu_malloc);
+	jit_popr_i(JIT_R1);
+	jit_movr_p(JIT_VHEAP, JIT_RET);
+	jit_movi_p(JIT_R2, gates->evaluate_value_const);
+	jit_str_p(JIT_VHEAP, JIT_R2);
+	jit_stxi_p(offsetof(PgfValuePAP,fun), JIT_VHEAP, JIT_VCLOS);
+	jit_stxi_p(offsetof(PgfValuePAP,n_args), JIT_VHEAP, JIT_R1);
 	next = jit_get_label();
 	ref  = jit_blei_i(jit_forward(), JIT_R1, 0);
 	jit_popr_p(JIT_R2);
-	jit_stxi_p(offsetof(PgfValue,args), JIT_RET, JIT_R2);
-	jit_addi_i(JIT_RET, JIT_RET, sizeof(void*));
+	jit_stxi_p(offsetof(PgfValuePAP,args), JIT_RET, JIT_R2);
+	jit_addi_p(JIT_RET, JIT_RET, sizeof(void*));
 	jit_subi_i(JIT_R1, JIT_R1, sizeof(void*));
 	jit_jmpi(next);
 	jit_patch(ref);
-	jit_jmpr(JIT_VCLOS);
+	jit_jmpi(enter_ret);
+	jit_patch(ref2);
+	jit_ldxi_p(JIT_VCLOS, JIT_FP, sizeof(void*));
+	jit_ldr_p(JIT_FP, JIT_FP);
+	jit_ldxi_i(JIT_R0, JIT_VCLOS, offsetof(PgfAbsFun,arity)-offsetof(PgfAbsFun,closure));
+	jit_muli_i(JIT_R0, JIT_R0, sizeof(PgfClosure*));
+	jit_addi_i(JIT_R0, JIT_R0, sizeof(void*));
+	jit_subr_p(JIT_R0, JIT_FP, JIT_R0);  // don't use jit_subr_p(JIT_SP, JIT_FP, JIT_R0) since it is dangerous on x86
+	jit_movr_p(JIT_SP, JIT_R0);
+	jit_jmpi(gates->mk_const);
+
+	pgf_jit_make_space(rdr, JIT_CODE_WINDOW*2);
+
+	gates->evaluate_gen = jit_get_ip().ptr;
+	jit_jmpi(gates->mk_const);
+
+	pgf_jit_make_space(rdr, JIT_CODE_WINDOW*2);
+
+	gates->evaluate_meta = jit_get_ip().ptr;
+	jit_jmpi(gates->mk_const);
 
 	gates->fin.fn = pgf_jit_finalize_cafs;
 	gates->cafs = NULL;
@@ -1134,15 +1104,21 @@ pgf_jit_function(PgfReader* rdr, PgfAbstr* abstr,
 			}
 			case PGF_INSTR_DROP: {
 				size_t n      = pgf_read_int(rdr);
+
+#ifdef PGF_JIT_DEBUG
+				gu_printf(out, err, "DROP        %d\n", n);
+#endif
+
+				jit_addi_p(JIT_SP, JIT_SP, n*sizeof(PgfClosure*));
+				break;
+			}
+			case PGF_INSTR_JUMP: {
 				size_t target = pgf_read_int(rdr);
 
 #ifdef PGF_JIT_DEBUG
-				gu_printf(out, err, "DROP        %d %03d\n", n, target);
+				gu_printf(out, err, "JUMP        %03d\n", target);
 #endif
-				
-				if (n > 0)
-					jit_addi_p(JIT_SP, JIT_SP, n*sizeof(PgfClosure*));
-				
+
 				jit_insn *jump =
 					jit_jmpi(jit_forward());
 
@@ -1151,7 +1127,6 @@ pgf_jit_function(PgfReader* rdr, PgfAbstr* abstr,
 				label_patch.ref     = jump;
 				label_patch.is_abs  = false;
 				gu_buf_push(rdr->jit_state->segment_patches, PgfSegmentPatch, label_patch);
-
 				break;
 			}
 			case PGF_INSTR_FAIL: