From e57804e6c27496c5a2822c517d833343a94fcadc Mon Sep 17 00:00:00 2001
From: Alexander Medvednikov <alexander@medvednikov.com>
Date: Sat, 21 Mar 2020 09:29:16 +0100
Subject: [PATCH] cgen: generate init()

---
 vlib/strings/builder_c.v |  4 +++-
 vlib/v/gen/cgen.v        | 41 +++++++++++++++++++++++-----------------
 vlib/v/gen/cgen_test.v   |  1 +
 vlib/v/gen/cheaders.v    |  3 ++-
 4 files changed, 30 insertions(+), 19 deletions(-)

diff --git a/vlib/strings/builder_c.v b/vlib/strings/builder_c.v
index db197e2a49..07d2eb9484 100644
--- a/vlib/strings/builder_c.v
+++ b/vlib/strings/builder_c.v
@@ -72,7 +72,9 @@ pub fn (b &Builder) after(n int) string {
 		return ''
 	}
 	buf := b.buf[n..]
-	return string(buf.clone())
+	mut copy := buf.clone()
+	copy << `\0`
+	return string(copy)
 }
 
 pub fn (b mut Builder) str() string {
diff --git a/vlib/v/gen/cgen.v b/vlib/v/gen/cgen.v
index d3f809e409..5b8c162adf 100644
--- a/vlib/v/gen/cgen.v
+++ b/vlib/v/gen/cgen.v
@@ -12,6 +12,7 @@ struct Gen {
 	out            strings.Builder
 	typedefs       strings.Builder
 	definitions    strings.Builder // typedefs, defines etc (everything that goes to the top of the file)
+	inits          strings.Builder // contents of `void _init(){}`
 	table          &table.Table
 mut:
 	fn_decl        &ast.FnDecl // pointer to the FnDecl we are currently inside otherwise 0
@@ -33,6 +34,7 @@ pub fn cgen(files []ast.File, table &table.Table) string {
 		out: strings.new_builder(100)
 		typedefs: strings.new_builder(100)
 		definitions: strings.new_builder(100)
+		inits: strings.new_builder(100)
 		table: table
 		fn_decl: 0
 	}
@@ -42,6 +44,9 @@ pub fn cgen(files []ast.File, table &table.Table) string {
 	}
 	g.write_variadic_types()
 	g.write_str_definitions()
+	g.writeln('void _init() {')
+	g.writeln(g.inits.str())
+	g.writeln('}')
 	return g.typedefs.str() + g.definitions.str() + g.out.str()
 }
 
@@ -1425,31 +1430,28 @@ fn (g mut Gen) const_decl(node ast.ConstDecl) {
 	for i, field in node.fields {
 		name := field.name.replace('.', '__')
 		expr := node.exprs[i]
+		// TODO hack. Cut the generated value and paste it into definitions.
+		pos := g.out.len
+		g.expr(expr)
+		val := g.out.after(pos)
+		g.out.go_back(val.len)
 		match expr {
-			// Simple expressions should use a #define
-			// so that we don't pollute the binary with unnecessary global vars
-			// Do not do this when building a module, otherwise the consts
-			// will not be accessible.
 			ast.CharLiteral, ast.IntegerLiteral {
+				// Simple expressions should use a #define
+				// so that we don't pollute the binary with unnecessary global vars
+				// Do not do this when building a module, otherwise the consts
+				// will not be accessible.
 				g.definitions.write('#define $name ')
-				// TODO hack. Cut the generated value and paste it into definitions.
-				g.write('//')
-				pos := g.out.len
-				g.expr(expr)
-				mut b := g.out.buf[pos..g.out.buf.len].clone()
-				b << `\0`
-				val := string(b)
-				// val += '\0'
-				// g.out.go_back(val.len)
-				// println('pos=$pos buf.len=$g.out.buf.len len=$g.out.len val.len=$val.len val="$val"\n')
-				g.writeln('')
 				g.definitions.writeln(val)
 			}
 			else {
+				// Initialize more complex consts in `void _init(){}`
+				// (C doesn't allow init expressions that can't be resolved at compile time).
 				styp := g.typ(field.typ)
 				g.definitions.writeln('$styp $name; // inited later') // = ')
-				// TODO
-				// g.expr(node.exprs[i])
+				g.inits.write('$name = ')
+				g.inits.write(val)
+				g.inits.writeln(';')
 			}
 	}
 	}
@@ -1534,6 +1536,11 @@ fn verror(s string) {
 	// exit(1)
 }
 
+fn (g mut Gen) write_init_function() {
+	g.writeln('void _init() {')
+	g.writeln('}')
+}
+
 fn (g mut Gen) write_str_definitions() {
 	// _STR function can't be defined in vlib
 	g.writeln('
diff --git a/vlib/v/gen/cgen_test.v b/vlib/v/gen/cgen_test.v
index 4bc320b576..e81ee5dc4b 100644
--- a/vlib/v/gen/cgen_test.v
+++ b/vlib/v/gen/cgen_test.v
@@ -48,6 +48,7 @@ fn compare_texts(a, b, path string) bool {
 
 	for i, line_a in lines_a {
 		if i >= lines_b.len {
+			println(line_a)
 			return false
 		}
 		line_b := lines_b[i]
diff --git a/vlib/v/gen/cheaders.v b/vlib/v/gen/cheaders.v
index 2d42d01dc5..504a7fde85 100644
--- a/vlib/v/gen/cheaders.v
+++ b/vlib/v/gen/cheaders.v
@@ -188,9 +188,10 @@ extern wchar_t **_wenviron;
 byte g_str_buf[1024];
 int load_so(byteptr);
 void reload_so();
+void _init();
 
 // ============== wyhash ==============
-//	Author: Wang Yi <godspeed_china@yeah.net>
+//	Author: Wang Yi
 #ifndef wyhash_version_4
 #define wyhash_version_4
 #include	<stdint.h>