harec

commit 031a921a7b929d8517d720cadf04c9c4e7da3148
parent 2773bd15433e9134c064bae8fc98c009c6a19d05
Author: Drew DeVault <sir@cmpwn.com>
Date:   Fri, 25 Dec 2020 16:18:54 -0500

gen: introduce function prelude, rehome allocations

This isn't super important now, but it'll matter later when we introduce
loops & branches and such what.

Diffstat:
M
include/qbe.h
 | 
11
++++++++---
M
src/emit.c
 | 
9
+++++++--
M
src/gen.c
 | 
10
++++++----
M
src/qbe.c
 | 
36
++++++++++++++++++++++++------------

4 files changed, 45 insertions(+), 21 deletions(-)
diff --git a/include/qbe.h b/include/qbe.h
@@ -175,11 +175,15 @@ struct qbe_func_param {
 	struct qbe_func_param *next;
 };
 
+struct qbe_statements {
+	size_t ln, sz;
+	struct qbe_statement *stmts;
+};
+
 struct qbe_func {
 	const struct qbe_type *returns;
 	struct qbe_func_param *params;
-	size_t blen, bsiz;
-	struct qbe_statement *body;
+	struct qbe_statements prelude, body;
 };
 
 enum qbe_deftype {
@@ -207,9 +211,10 @@ void qbe_append_def(struct qbe_program *prog, struct qbe_def *def);
 void geni(struct qbe_statement *stmt, const struct qbe_value *out, enum qbe_instr instr, ...);
 const char *genl(struct qbe_statement *stmt, uint64_t *id, const char *fmt);
 void pushi(struct qbe_func *func, const struct qbe_value *out, enum qbe_instr instr, ...);
+void pushprei(struct qbe_func *func, const struct qbe_value *out, enum qbe_instr instr, ...);
 const char *pushl(struct qbe_func *func, uint64_t *id, const char *fmt);
 void pushc(struct qbe_func *func, const char *fmt, ...);
-void push(struct qbe_func *func, struct qbe_statement *stmt);
+void push(struct qbe_statements *stmts, struct qbe_statement *stmt);
 
 struct qbe_value *qval_dup(const struct qbe_value *val);
 
diff --git a/src/emit.c b/src/emit.c
@@ -147,8 +147,13 @@ emit_func(struct qbe_def *def, FILE *out)
 	}
 	fprintf(out, ") {\n");
 
-	for (size_t i = 0; i < def->func.blen; ++i) {
-		struct qbe_statement *stmt = &def->func.body[i];
+	for (size_t i = 0; i < def->func.prelude.ln; ++i) {
+		struct qbe_statement *stmt = &def->func.prelude.stmts[i];
+		emit_stmt(stmt, out);
+	}
+
+	for (size_t i = 0; i < def->func.body.ln; ++i) {
+		struct qbe_statement *stmt = &def->func.body.stmts[i];
 		emit_stmt(stmt, out);
 	}
 
diff --git a/src/gen.c b/src/gen.c
@@ -56,7 +56,7 @@ alloc_temp(struct gen_context *ctx, struct qbe_value *val,
 
 	struct qbe_value size;
 	constl(&size, type->size);
-	pushi(ctx->current, val, alloc_for_align(type->align), &size, NULL);
+	pushprei(ctx->current, val, alloc_for_align(type->align), &size, NULL);
 }
 
 static struct gen_binding *
@@ -315,7 +315,7 @@ gen_call(struct gen_context *ctx,
 		next = &arg->next;
 	}
 
-	push(ctx->current, &call);
+	push(&ctx->current->body, &call);
 }
 
 static void
@@ -555,7 +555,9 @@ gen_function_decl(struct gen_context *ctx, const struct declaration *decl)
 	qdef->func.returns = qtype_for_type(ctx, fntype->func.result, false);
 	ctx->current = &qdef->func;
 
-	pushl(&qdef->func, &ctx->id, "start.%d");
+	struct qbe_statement start_label = {0};
+	genl(&start_label, &ctx->id, "start.%d");
+	push(&qdef->func.prelude, &start_label);
 
 	struct qbe_func_param *param, **next = &qdef->func.params;
 	struct scope_object *obj = decl->func.scope->objects;
@@ -600,7 +602,7 @@ gen_function_decl(struct gen_context *ctx, const struct declaration *decl)
 
 	pushl(&qdef->func, &ctx->id, "body.%d");
 	gen_expression(ctx, func->body, ctx->return_value);
-	push(&qdef->func, &end_label);
+	push(&qdef->func.body, &end_label);
 
 	if (fntype->func.result->storage != TYPE_STORAGE_VOID) {
 		struct qbe_value load = {0};
diff --git a/src/qbe.c b/src/qbe.c
@@ -209,18 +209,18 @@ genl(struct qbe_statement *stmt, uint64_t *id, const char *fmt)
 }
 
 void
-push(struct qbe_func *func, struct qbe_statement *stmt)
+push(struct qbe_statements *stmts, struct qbe_statement *stmt)
 {
-	if (!func->body) {
-		func->bsiz = 256;
-		func->blen = 0;
-		func->body = xcalloc(1, sizeof(struct qbe_statement) * func->bsiz);
+	if (!stmts->stmts) {
+		stmts->sz = 256;
+		stmts->ln = 0;
+		stmts->stmts = xcalloc(1, sizeof(struct qbe_statement) * stmts->sz);
 	}
-	if (func->blen + 1 < func->bsiz) {
-		func->bsiz *= 2;
-		func->body = xrealloc(func->body, func->bsiz);
+	if (stmts->ln + 1 < stmts->sz) {
+		stmts->sz *= 2;
+		stmts->stmts = xrealloc(stmts->stmts, stmts->sz);
 	}
-	func->body[func->blen++] = *stmt;
+	stmts->stmts[stmts->ln++] = *stmt;
 }
 
 void
@@ -232,7 +232,19 @@ pushi(struct qbe_func *func, const struct qbe_value *out,
 	va_start(ap, instr);
 	va_geni(&stmt, instr, out, ap);
 	va_end(ap);
-	push(func, &stmt);
+	push(&func->body, &stmt);
+}
+
+void
+pushprei(struct qbe_func *func, const struct qbe_value *out,
+		enum qbe_instr instr, ...)
+{
+	struct qbe_statement stmt = {0};
+	va_list ap;
+	va_start(ap, instr);
+	va_geni(&stmt, instr, out, ap);
+	va_end(ap);
+	push(&func->prelude, &stmt);
 }
 
 const char *
@@ -240,7 +252,7 @@ pushl(struct qbe_func *func, uint64_t *id, const char *fmt)
 {
 	struct qbe_statement stmt = {0};
 	const char *l = genl(&stmt, id, fmt);
-	push(func, &stmt);
+	push(&func->body, &stmt);
 	return l;
 }
 
@@ -260,7 +272,7 @@ pushc(struct qbe_func *func, const char *fmt, ...)
 	va_end(ap);
 
 	stmt.comment = str;
-	push(func, &stmt);
+	push(&func->body, &stmt);
 }
 
 void