template: Add a function prologue like all other backends do.

ir/be/TEMPLATE/TEMPLATE_emitter.c

@@ -167,20 +167,6 @@ static void emit_be_IncSP(const ir_node *node)
 	TEMPLATE_emitf(node, "%s %S0, %d, %D0", op, offset);
 }
 
-static void emit_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);
-
-	/* emit function prolog */
-
-	/* allocate stackframe */
-	if (size > 0) {
-		TEMPLATE_emitf(node, "sub %%sp, %u, %%sp", size);
-	}
-}
-
 static void emit_Return(const ir_node *node)
 {
 	ir_graph *irg        = get_irn_irg(node);
@@ -217,7 +203,6 @@ static void TEMPLATE_register_emitters(void)
 	/* custom emitters not provided by the spec */
 	be_set_emitter(op_TEMPLATE_Jmp,    emit_TEMPLATE_Jmp);
 	be_set_emitter(op_TEMPLATE_Return, emit_Return);
-	be_set_emitter(op_TEMPLATE_Start,  emit_Start);
 	be_set_emitter(op_be_IncSP,        emit_be_IncSP);
 }
 

ir/be/TEMPLATE/TEMPLATE_spec.pl

@@ -172,6 +172,7 @@ Start => {
 	out_reqs  => [ "sp:I", "r0", "r1", "r2", "r3", "mem" ],
 	outs      => [ "stack", "arg0", "arg1", "arg2", "arg3", "M" ],
 	ins       => [],
+	emit      => "",
 },
 
 Return => {

ir/be/TEMPLATE/bearch_TEMPLATE.c

@@ -15,6 +15,7 @@
 #include "bemodule.h"
 #include "benode.h"
 #include "bera.h"
+#include "besched.h"
 #include "bestack.h"
 #include "debug.h"
 #include "gen_TEMPLATE_regalloc_if.h"
@@ -58,6 +59,19 @@ static const regalloc_if_t TEMPLATE_regalloc_if = {
 	.new_reload  = TEMPLATE_new_reload,
 };
 
+static void introduce_prologue(ir_graph *const irg)
+{
+	arch_register_t const *const sp         = &TEMPLATE_registers[REG_SP];
+	ir_node               *const start      = get_irg_start(irg);
+	ir_node               *const block      = get_nodes_block(start);
+	ir_node               *const initial_sp = be_get_initial_reg_value(irg, sp);
+	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, block, initial_sp, frame_size, 0);
+	edges_reroute_except(initial_sp, incsp, incsp);
+	sched_add_after(start, incsp);
+}
+
 static void TEMPLATE_generate_code(FILE *output, const char *cup_name)
 {
 	be_begin(output, cup_name);
@@ -75,6 +89,8 @@ static void TEMPLATE_generate_code(FILE *output, const char *cup_name)
 
 		be_step_regalloc(irg, &TEMPLATE_regalloc_if);
 
+		introduce_prologue(irg);
+
 		be_fix_stack_nodes(irg, &TEMPLATE_registers[REG_SP]);
 		be_birg_from_irg(irg)->non_ssa_regs = NULL;