markused: skip unused symbols, dump fns and generic specialization (fix #24921) (fix #24927) (#24924)

Author: felipensp

cmd/v/v.v

@@ -12,6 +12,7 @@ import v.util.version
 import v.builder
 import v.builder.cbuilder
 
+@[markused]
 const external_tools = [
 	'ast',
 	'bin2v',

vlib/gg/gg.v

@@ -32,6 +32,7 @@ pub:
 	thickness f32         = 1
 }
 
+@[markused]
 pub struct Size {
 pub mut:
 	width  int

vlib/gg/image.c.v

@@ -9,7 +9,7 @@ import sokol.sgl
 
 // Image holds the fields and data needed to
 // represent a bitmap/pixel based image in memory.
-@[heap]
+@[heap; markused]
 pub struct Image {
 pub mut:
 	id          int

vlib/gx/color.v

@@ -112,6 +112,7 @@ pub const light_red = Color{
 }
 
 // Color represents a 32 bit color value in sRGB format
+@[markused]
 pub struct Color {
 pub mut:
 	r u8

vlib/gx/text.v

@@ -4,7 +4,7 @@ module gx
 pub const align_left = HorizontalAlign.left
 pub const align_right = HorizontalAlign.right
 
-@[params]
+@[markused; params]
 pub struct TextCfg {
 pub:
 	color          Color           = black

vlib/os/os.c.v

@@ -9,6 +9,7 @@ $if freebsd || openbsd {
 	#include <sys/sysctl.h>
 }
 
+@[markused]
 pub const args = arguments()
 
 fn C.readdir(voidptr) &C.dirent

vlib/v/ast/ast.v

@@ -453,6 +453,7 @@ pub:
 pub mut:
 	language Language
 	fields   []StructField
+	idx      int
 }
 
 pub struct Embed {
@@ -1484,6 +1485,7 @@ pub:
 	comments []Comment
 pub mut:
 	parent_type Type
+	is_markused bool
 }
 
 // SumTypeDecl is the ast node for `type MySumType = string | int`
@@ -1497,7 +1499,8 @@ pub:
 	generic_types []Type
 	attrs         []Attr // attributes of type declaration
 pub mut:
-	variants []TypeNode
+	variants    []TypeNode
+	is_markused bool
 }
 
 pub struct FnTypeDecl {
@@ -1510,6 +1513,7 @@ pub:
 	comments      []Comment
 	generic_types []Type
 	attrs         []Attr // attributes of type declaration
+	is_markused   bool
 }
 
 // TODO: handle this differently

vlib/v/ast/table.v

@@ -34,6 +34,7 @@ pub mut:
 	used_fns       map[string]bool // filled in by markused
 	used_consts    map[string]bool // filled in by markused
 	used_globals   map[string]bool // filled in by markused
+	used_syms      map[int]bool    // filled in by markused
 	used_veb_types []Type          // veb context types, filled in by checker
 	used_maps      int             // how many times maps were used, filled in by markused
 	used_arrays    int             // how many times arrays were used, filled in by markused
@@ -42,6 +43,7 @@ pub mut:
 	// json             bool            // json is imported
 	debugger       bool            // debugger is used
 	comptime_calls map[string]bool // resolved name to call on comptime
+	comptime_syms  map[int]bool    // resolved syms (generic)
 	comptime_for   bool            // uses $for
 	memory_align   bool            // @[aligned] for struct
 }

vlib/v/ast/types.v

@@ -183,6 +183,7 @@ pub mut:
 	is_anon        bool
 	is_generic     bool
 	is_shared      bool
+	is_markused    bool
 	has_option     bool // contains any option field
 	generic_types  []Type
 	concrete_types []Type

vlib/v/checker/checker.v

@@ -3137,6 +3137,10 @@ pub fn (mut c Checker) expr(mut node ast.Expr) ast.Type {
 			c.inside_if_guard = true
 			node.expr_type = c.expr(mut node.expr)
 			c.inside_if_guard = old_inside_if_guard
+			if c.pref.skip_unused && node.expr_type.has_flag(.generic) {
+				unwrapped_type := c.unwrap_generic(node.expr_type)
+				c.table.used_features.comptime_syms[unwrapped_type] = true
+			}
 			if !node.expr_type.has_flag(.option) && !node.expr_type.has_flag(.result) {
 				mut no_opt_or_res := true
 				match mut node.expr {
@@ -3435,6 +3439,9 @@ fn (mut c Checker) cast_expr(mut node ast.CastExpr) ast.Type {
 		// allow conversion from none to every option type
 	} else if to_sym.kind == .sum_type {
 		to_sym_info := to_sym.info as ast.SumType
+		if c.pref.skip_unused && to_sym_info.concrete_types.len > 0 {
+			c.table.used_features.comptime_syms[to_type] = true
+		}
 		if to_sym_info.generic_types.len > 0 && to_sym_info.concrete_types.len == 0 {
 			c.error('generic sumtype `${to_sym.name}` must specify type parameter, e.g. ${to_sym.name}[int]',
 				node.pos)
@@ -5227,6 +5234,9 @@ fn (mut c Checker) chan_init(mut node ast.ChanInit) ast.Type {
 		if node.has_cap {
 			c.check_array_init_para_type('cap', mut node.cap_expr, node.pos)
 		}
+		if c.pref.skip_unused && node.typ.has_flag(.generic) {
+			c.table.used_features.comptime_syms[c.unwrap_generic(node.typ)] = true
+		}
 		return node.typ
 	} else {
 		c.error('`chan` of unknown type', node.pos)