arm: perform prolog/epilogue lowering

ir/be/arm/arm_emitter.c

@@ -657,32 +657,6 @@ static void emit_be_MemPerm(const ir_node *node)
 	assert(sp_change == 0);
 }
 
-static void emit_arm_Start(const ir_node *node)
-{
-	ir_graph *irg        = get_irn_irg(node);
-	ir_type  *frame_type = get_irg_frame_type(irg);
-	unsigned  size       = get_type_size_bytes(frame_type);
-
-	/* allocate stackframe */
-	if (size > 0) {
-		arm_emitf(node, "sub sp, sp, #0x%X", size);
-	}
-}
-
-static void emit_arm_Return(const ir_node *node)
-{
-	ir_graph *irg        = get_irn_irg(node);
-	ir_type  *frame_type = get_irg_frame_type(irg);
-	unsigned  size       = get_type_size_bytes(frame_type);
-
-	/* deallocate stackframe */
-	if (size > 0) {
-		arm_emitf(node, "add sp, sp, #0x%X", size);
-	}
-	arm_emitf(node, "mov pc, lr");
-}
-
-
 static void emit_arm_Jmp(const ir_node *node)
 {
 	ir_node *block, *next_block;
@@ -720,18 +694,15 @@ static void arm_register_emitters(void)
 	be_set_emitter(op_arm_fConst,    emit_arm_fConst);
 	be_set_emitter(op_arm_FrameAddr, emit_arm_FrameAddr);
 	be_set_emitter(op_arm_Jmp,       emit_arm_Jmp);
-	be_set_emitter(op_arm_Return,    emit_arm_Return);
-	be_set_emitter(op_arm_Start,     emit_arm_Start);
+	be_set_emitter(op_arm_Start,     be_emit_nothing);
 	be_set_emitter(op_arm_SwitchJmp, emit_arm_SwitchJmp);
 	be_set_emitter(op_be_Copy,       emit_be_Copy);
 	be_set_emitter(op_be_CopyKeep,   emit_be_Copy);
 	be_set_emitter(op_be_IncSP,      emit_be_IncSP);
+	be_set_emitter(op_be_Keep,       be_emit_nothing);
 	be_set_emitter(op_be_MemPerm,    emit_be_MemPerm);
 	be_set_emitter(op_be_Perm,       emit_be_Perm);
-
-	/* no need to emit anything for the following nodes */
-	be_set_emitter(op_Phi,     be_emit_nothing);
-	be_set_emitter(op_be_Keep, be_emit_nothing);
+	be_set_emitter(op_Phi,           be_emit_nothing);
 }
 
 /**

ir/be/arm/arm_finish.c

+/*
+ * This file is part of libFirm.
+ * Copyright (C) 2014 University of Karlsruhe.
+ */
+
+/**
+ * @file
+ * @brief   arm graph touchups before emitting
+ * @author  Matthias Braun
+ */
+#include "bearch_arm_t.h"
+
+#include "firm_types.h"
+#include "irgwalk.h"
+
+#include "bespillslots.h"
+#include "bestack.h"
+#include "be_types.h"
+#include "beirg.h"
+#include "benode.h"
+#include "besched.h"
+
+#include "arm_new_nodes.h"
+#include "gen_arm_regalloc_if.h"
+#include "arm_optimize.h"
+
+static bool is_frame_load(const ir_node *node)
+{
+	return is_arm_Ldr(node) || is_arm_Ldf(node);
+}
+
+static void arm_collect_frame_entity_nodes(ir_node *node, void *data)
+{
+	if (!is_frame_load(node))
+		return;
+
+	const arm_load_store_attr_t *attr = get_arm_load_store_attr_const(node);
+	if (!attr->is_frame_entity)
+		return;
+	const ir_entity *entity = attr->entity;
+	if (entity != NULL)
+		return;
+	const ir_mode *mode = attr->load_store_mode;
+	const ir_type *type = get_type_for_mode(mode);
+
+	be_fec_env_t *env = (be_fec_env_t*)data;
+	be_load_needs_frame_entity(env, node, type);
+}
+
+static void arm_set_frame_entity(ir_node *node, ir_entity *entity,
+                                 const ir_type *type)
+{
+	(void)type;
+	arm_load_store_attr_t *attr = get_arm_load_store_attr(node);
+	attr->entity = entity;
+}
+
+static void introduce_epilog(ir_node *ret)
+{
+	arch_register_t const *const sp_reg = &arm_registers[REG_SP];
+	assert(arch_get_irn_register_req_in(ret, n_arm_Return_sp) == sp_reg->single_req);
+
+	ir_node  *const sp         = get_irn_n(ret, n_arm_Return_sp);
+	ir_node  *const block      = get_nodes_block(ret);
+	ir_graph *const irg        = get_irn_irg(ret);
+	ir_type  *const frame_type = get_irg_frame_type(irg);
+	unsigned  const frame_size = get_type_size_bytes(frame_type);
+	ir_node  *const incsp      = be_new_IncSP(sp_reg, block, sp, -frame_size, 0);
+	set_irn_n(ret, n_arm_Return_sp, incsp);
+	sched_add_before(ret, incsp);
+}
+
+static void introduce_prolog_epilog(ir_graph *irg)
+{
+	/* introduce epilog for every return node */
+	foreach_irn_in(get_irg_end_block(irg), i, ret) {
+		assert(is_arm_Return(ret));
+		introduce_epilog(ret);
+	}
+
+	const arch_register_t *sp_reg     = &arm_registers[REG_SP];
+	ir_node               *start      = get_irg_start(irg);
+	ir_node               *block      = get_nodes_block(start);
+	ir_node               *initial_sp = be_get_initial_reg_value(irg, sp_reg);
+	ir_node               *schedpoint = start;
+	ir_type               *frame_type = get_irg_frame_type(irg);
+	unsigned               frame_size = get_type_size_bytes(frame_type);
+
+	while (be_is_Keep(sched_next(schedpoint)))
+		schedpoint = sched_next(schedpoint);
+
+	ir_node *const incsp = be_new_IncSP(sp_reg, block, initial_sp, frame_size, 0);
+	edges_reroute_except(initial_sp, incsp, incsp);
+	sched_add_after(schedpoint, incsp);
+}
+
+void arm_finish_graph(ir_graph *irg)
+{
+	be_stack_layout_t *stack_layout = be_get_irg_stack_layout(irg);
+	bool               at_begin     = stack_layout->sp_relative;
+	be_fec_env_t      *fec_env      = be_new_frame_entity_coalescer(irg);
+
+	irg_walk_graph(irg, NULL, arm_collect_frame_entity_nodes, fec_env);
+	be_assign_entities(fec_env, arm_set_frame_entity, at_begin);
+	be_free_frame_entity_coalescer(fec_env);
+
+	introduce_prolog_epilog(irg);
+
+	/* fix stack entity offsets */
+	be_abi_fix_stack_nodes(irg);
+	be_abi_fix_stack_bias(irg);
+
+	/* do peephole optimizations and fix stack offsets */
+	arm_peephole_optimization(irg);
+}

ir/be/arm/arm_nodes_attr.h

@@ -46,6 +46,11 @@ enum fpa_immediates {
 	fpa_max
 };
 
+enum n_arm_Return {
+	n_arm_Return_mem = 0,
+	n_arm_Return_sp  = 1,
+};
+
 /** Generic ARM node attributes. */
 typedef struct arm_attr_t {
 	except_attr                 exc;                /**< the exception attribute. MUST be the first one. */

ir/be/arm/arm_spec.pl

@@ -556,6 +556,7 @@ Return => {
 	arity    => "variable",
 	mode     => "mode_X",
 	reg_req  => { out => [ "none" ] },
+	emit     => "bx lr",
 },
 
 ); # end of %nodes

ir/be/arm/bearch_arm.c

@@ -31,7 +31,6 @@
 #include "be.h"
 #include "bemodule.h"
 #include "beirg.h"
-#include "bespillslots.h"
 #include "bespillutil.h"
 #include "beutil.h"
 #include "begnuas.h"
@@ -84,14 +83,7 @@ static void arm_set_stack_bias(ir_node *irn, int bias)
 
 static int arm_get_sp_bias(const ir_node *node)
 {
-	if (is_arm_Start(node)) {
-		ir_graph *irg        = get_irn_irg(node);
-		ir_type  *frame_type = get_irg_frame_type(irg);
-		unsigned  size       = get_type_size_bytes(frame_type);
-		return size;
-	} else if (is_arm_Return(node)) {
-		return SP_BIAS_RESET;
-	}
+	(void)node;
 	return 0;
 }
 
@@ -124,37 +116,6 @@ static void arm_prepare_graph(ir_graph *irg)
 	place_code(irg);
 }
 
-static bool is_frame_load(const ir_node *node)
-{
-	return is_arm_Ldr(node) || is_arm_Ldf(node);
-}
-
-static void arm_collect_frame_entity_nodes(ir_node *node, void *data)
-{
-	if (!is_frame_load(node))
-		return;
-
-	const arm_load_store_attr_t *attr = get_arm_load_store_attr_const(node);
-	if (!attr->is_frame_entity)
-		return;
-	const ir_entity *entity = attr->entity;
-	if (entity != NULL)
-		return;
-	const ir_mode *mode = attr->load_store_mode;
-	const ir_type *type = get_type_for_mode(mode);
-
-	be_fec_env_t *env = (be_fec_env_t*)data;
-	be_load_needs_frame_entity(env, node, type);
-}
-
-static void arm_set_frame_entity(ir_node *node, ir_entity *entity,
-                                 const ir_type *type)
-{
-	(void)type;
-	arm_load_store_attr_t *attr = get_arm_load_store_attr(node);
-	attr->entity = entity;
-}
-
 static ir_node *arm_new_reload(ir_node *value, ir_node *spill, ir_node *before)
 {
 	ir_node  *block  = get_block(before);
@@ -185,22 +146,7 @@ static ir_node *arm_new_spill(ir_node *value, ir_node *after)
 
 static void arm_emit(ir_graph *irg)
 {
-	be_stack_layout_t *stack_layout = be_get_irg_stack_layout(irg);
-	bool               at_begin     = stack_layout->sp_relative;
-	be_fec_env_t      *fec_env      = be_new_frame_entity_coalescer(irg);
-
-	irg_walk_graph(irg, NULL, arm_collect_frame_entity_nodes, fec_env);
-	be_assign_entities(fec_env, arm_set_frame_entity, at_begin);
-	be_free_frame_entity_coalescer(fec_env);
-
-	/* fix stack entity offsets */
-	be_abi_fix_stack_nodes(irg);
-	be_abi_fix_stack_bias(irg);
-
-	/* do peephole optimizations and fix stack offsets */
-	arm_peephole_optimization(irg);
-
-	/* emit code */
+	arm_finish_graph(irg);
 	arm_emit_function(irg);
 }
 

ir/be/arm/bearch_arm_t.h

@@ -121,4 +121,6 @@ struct arm_isa_t {
 	int            fpu_arch;      /**< FPU architecture */
 };
 
+void arm_finish_graph(ir_graph *irg);
+
 #endif