all: remove `rwshared` keyword, make its semantics default for `shared` (#5710)

doc/upcoming.md

@@ -35,13 +35,20 @@ atomic d := ...
 - `c` can be passed to coroutines an accessed
   *concurrently*.<sup>2</sup> In order to avoid data races it has to
   be locked before access can occur and unlocked to allow access to
-  other coroutines. This is done by the following block structure:
+  other coroutines. This is done by one the following block structures:
   ```v
   lock c {
       // read, modify, write c
       ...
   }
   ```
+  
+  ```v
+  rlock c {
+      // read c
+      ...
+  }
+  ```
   Several variables may be specified: `lock x, y, z { ... }`.
   They are unlocked in the opposite order.
 - `d` can be passed to coroutines and accessed *concurrently*,

vlib/builtin/cfns.c.v

@@ -402,6 +402,7 @@ fn C.pthread_mutex_unlock(voidptr) int
 
 fn C.pthread_rwlockattr_init(voidptr) int
 fn C.pthread_rwlockattr_setkind_np(voidptr, int) int
+fn C.pthread_rwlockattr_setpshared(voidptr, int) int
 fn C.pthread_rwlock_init(voidptr, voidptr) int
 fn C.pthread_rwlock_rdlock(voidptr) int
 fn C.pthread_rwlock_wrlock(voidptr) int

vlib/sync/sync_nix.c.v

@@ -33,6 +33,7 @@ pub fn new_rwmutex() &RwMutex {
 	C.pthread_rwlockattr_init(&a.attr)
 	// Give writer priority over readers
 	C.pthread_rwlockattr_setkind_np(&a.attr, C.PTHREAD_RWLOCK_PREFER_WRITER_NONRECURSIVE_NP)
+	C.pthread_rwlockattr_setpshared(&a.attr, C.PTHREAD_PROCESS_PRIVATE)
 	C.pthread_rwlock_init(&m.mutex, &a.attr)
 	return m
 }

vlib/v/ast/ast.v

@@ -450,7 +450,6 @@ pub:
 pub mut:
 	lockeds  []Ident // `x`, `y` in `lock x, y {`
 	is_expr  bool
-	is_rw    bool // `rwshared` needs special special handling even in `lock` case
 	typ      table.Type
 }
 

vlib/v/checker/checker.v

@@ -1158,9 +1158,6 @@ pub fn (mut c Checker) call_fn(mut call_expr ast.CallExpr) table.Type {
 				if call_arg.share == .shared_t {
 					words = 'shared'
 					tok = 'shared'
-				} else if call_arg.share == .rwshared_t {
-					words = 'read/write shared'
-					tok = 'rwshared'
 				} else if call_arg.share == .atomic_t {
 					words = 'atomic'
 					tok = 'atomic'
@@ -1176,9 +1173,6 @@ pub fn (mut c Checker) call_fn(mut call_expr ast.CallExpr) table.Type {
 				if arg.typ.share() == .shared_t {
 					words = ' shared'
 					tok = 'shared'
-				} else if arg.typ.share() == .rwshared_t {
-					words = ' read/write shared'
-					tok = 'rwshared'
 				} else if arg.typ.share() == .atomic_t {
 					words = 'n atomic'
 					tok = 'atomic'
@@ -1572,11 +1566,11 @@ pub fn (mut c Checker) assign_stmt(mut assign_stmt ast.AssignStmt) {
 					}
 					mut scope := c.file.scope.innermost(assign_stmt.pos.pos)
 					mut ident_var_info := left.var_info()
-					if ident_var_info.share in [.shared_t, .rwshared_t] {
+					if ident_var_info.share == .shared_t {
 						left_type = left_type.set_flag(.shared_f)
 					}
-					if ident_var_info.share in [.atomic_t, .rwshared_t] {
+					if ident_var_info.share == .atomic_t {
-						left_type = left_type.set_flag(.atomic_or_rw)
+						left_type = left_type.set_flag(.atomic_f)
 					}
 					assign_stmt.left_types[i] = left_type
 					ident_var_info.typ = left_type

vlib/v/gen/cgen.v

@@ -59,10 +59,8 @@ mut:
 	is_amp               bool // for `&Foo{}` to merge PrefixExpr `&` and StructInit `Foo{}`; also for `&byte(0)` etc
 	is_sql               bool // Inside `sql db{}` statement, generating sql instead of C (e.g. `and` instead of `&&` etc)
 	is_shared            bool // for initialization of hidden mutex in `[rw]shared` literals
-	is_rwshared          bool
 	optionals            []string // to avoid duplicates TODO perf, use map
 	shareds              []int // types with hidden mutex for which decl has been emitted
-	rwshareds            []int // same with hidden rwmutex
 	inside_ternary       int // ?: comma separated statements on a single line
 	inside_map_postfix   bool // inside map++/-- postfix expr
 	inside_map_infix     bool // inside map<</+=/-= infix expr
@@ -408,22 +406,16 @@ fn (mut g Gen) register_optional(t table.Type) string {
 }
 
 fn (mut g Gen) find_or_register_shared(t table.Type, base string) string {
-	is_rw := t.has_flag(.atomic_or_rw)
+	sh_typ :=  '__shared__$base'
-	prefix := if is_rw { 'rw' } else { '' }
-	sh_typ :=  '__${prefix}shared__$base'
 	t_idx := t.idx()
-	if (is_rw && t_idx in g.rwshareds) || (!is_rw && t_idx in g.shareds) {
+	if t_idx in g.shareds {
 		return sh_typ
 	}
-	mtx_typ := if is_rw { 'sync__RwMutex' } else { 'sync__Mutex' }
+	mtx_typ := 'sync__RwMutex'
 	g.hotcode_definitions.writeln('struct $sh_typ { $base val; $mtx_typ* mtx; };')
 	g.typedefs2.writeln('typedef struct $sh_typ $sh_typ;')
 	// println('registered shared type $sh_typ')
-	if is_rw {
+	g.shareds << t_idx
-		g.rwshareds << t_idx
-	} else {
-		g.shareds << t_idx
-	}
 	return sh_typ
 }
 
@@ -1192,11 +1184,11 @@ fn (mut g Gen) gen_assign_stmt(assign_stmt ast.AssignStmt) {
 			blank_assign = ident.kind == .blank_ident
 			if ident.info is ast.IdentVar {
 				share := (ident.info as ast.IdentVar).share
-				if share in [.shared_t, .rwshared_t] {
+				if share == .shared_t {
 					var_type = var_type.set_flag(.shared_f)
 				}
-				if share in [.atomic_t, .rwshared_t] {
+				if share == .atomic_t {
-					var_type = var_type.set_flag(.atomic_or_rw)
+					var_type = var_type.set_flag(.atomic_f)
 				}
 			}
 		}
@@ -1327,7 +1319,6 @@ fn (mut g Gen) gen_assign_stmt(assign_stmt ast.AssignStmt) {
 				g.write('*($styp*)')
 			}
 			g.is_shared = var_type.has_flag(.shared_f)
-			g.is_rwshared = var_type.has_flag(.atomic_or_rw)
 			if !cloned {
 				if is_decl {
 					if is_fixed_array_init && !has_val {
@@ -1353,7 +1344,6 @@ fn (mut g Gen) gen_assign_stmt(assign_stmt ast.AssignStmt) {
 				g.write(' })')
 				g.is_array_set = false
 			}
-			g.is_rwshared = false
 			g.is_shared = false
 		}
 		g.right_is_opt = false
@@ -2073,17 +2063,10 @@ fn (mut g Gen) lock_expr(node ast.LockExpr) {
 	mut lock_prefixes := []byte{len: 0, cap: node.lockeds.len}
 	for id in node.lockeds {
 		name := id.name
-		// fields of `id` itself have no valid information, so look up type(flags) in scope
-		obj := g.file.scope.innermost(id.pos.pos).find(name) or {
-			verror('cgen: unable to get type for lock variable $name')
-			ast.ScopeObject{}
-		}
-		typ := if obj is ast.Var { (*(obj as ast.Var)).typ } else { table.Type(0) }
 		deref := if id.is_mut { '->' } else { '.' }
-		lock_prefix := if node.is_rlock { `r` } else { if typ.has_flag(.atomic_or_rw) { `w` } else { `m` } }
+		lock_prefix := if node.is_rlock { `r` } else { `w` }
 		lock_prefixes << lock_prefix // keep for unlock
-		mut_prefix := if lock_prefix == `m` { '' } else { 'Rw' }
+		g.writeln('sync__RwMutex_${lock_prefix:c}_lock(${name}${deref}mtx);')
-		g.writeln('sync__${mut_prefix}Mutex_${lock_prefix:c}_lock(${name}${deref}mtx);')
 	}
 	g.stmts(node.stmts)
 	// unlock in reverse order
@@ -2092,9 +2075,7 @@ fn (mut g Gen) lock_expr(node ast.LockExpr) {
 		lock_prefix := lock_prefixes[i]
 		name := id.name
 		deref := if id.is_mut { '->' } else { '.' }
-		mut_prefix := if lock_prefix == `m` { '' } else { 'Rw' }
+		g.writeln('sync__RwMutex_${lock_prefix:c}_unlock(${name}${deref}mtx);')
-		unlock_type := if lock_prefix == `m` { '' } else { '${lock_prefix:c}_' }
-		g.writeln('sync__${mut_prefix}Mutex_${unlock_type}unlock(${name}${deref}mtx);')
 	}
 }
 
@@ -2237,7 +2218,7 @@ fn (mut g Gen) ident(node ast.Ident) {
 			g.write('(*($styp*)${name}.data)')
 			return
 		}
-		if !g.is_assign_lhs && (ident_var.share == .shared_t || ident_var.share == .rwshared_t) {
+		if !g.is_assign_lhs && ident_var.share == .shared_t {
 			g.write('${name}.val')
 			return
 		}
@@ -2763,7 +2744,6 @@ const (
 fn (mut g Gen) struct_init(struct_init ast.StructInit) {
 	styp := g.typ(struct_init.typ)
 	mut shared_styp := '' // only needed for shared &St{...
-	mut share_prefix := '' // 'rw' for `rwshared`
 	if styp in skip_struct_init {
 		g.go_back_out(3)
 		return
@@ -2775,10 +2755,6 @@ fn (mut g Gen) struct_init(struct_init ast.StructInit) {
 		g.out.go_back(1) // delete the `&` already generated in `prefix_expr()
 		if g.is_shared {
 			mut shared_typ := struct_init.typ.set_flag(.shared_f)
-			if g.is_rwshared {
-				shared_typ = shared_typ.set_flag(.atomic_or_rw)
-				share_prefix = 'rw'
-			}
 			shared_styp = g.typ(shared_typ)
 			g.writeln('($shared_styp*)memdup(&($shared_styp){.val = ($styp){')
 		} else {
@@ -2883,7 +2859,7 @@ fn (mut g Gen) struct_init(struct_init ast.StructInit) {
 	}
 	g.write('}')
 	if g.is_shared {
-		g.write(', .mtx = sync__new_${share_prefix}mutex()}')
+		g.write(', .mtx = sync__new_rwmutex()}')
 		if is_amp {
 			g.write(', sizeof($shared_styp))')
 		}

vlib/v/parser/fn.v

@@ -100,16 +100,16 @@ pub fn (mut p Parser) call_expr(language table.Language, mod string) ast.CallExp
 pub fn (mut p Parser) call_args() []ast.CallArg {
 	mut args := []ast.CallArg{}
 	for p.tok.kind != .rpar {
-		is_shared := p.tok.kind in [.key_shared, .key_rwshared]
+		is_shared := p.tok.kind == .key_shared
-		is_atomic_or_rw := p.tok.kind in [.key_rwshared, .key_atomic]
+		is_atomic := p.tok.kind == .key_atomic
-		is_mut := p.tok.kind == .key_mut || is_shared || is_atomic_or_rw
+		is_mut := p.tok.kind == .key_mut || is_shared || is_atomic
 		if is_mut {
 			p.next()
 		}
 		e := p.expr(0)
 		args << ast.CallArg{
 			is_mut: is_mut
-			share: table.sharetype_from_flags(is_shared, is_atomic_or_rw)
+			share: table.sharetype_from_flags(is_shared, is_atomic)
 			expr: e
 		}
 		if p.tok.kind != .rpar {
@@ -151,9 +151,9 @@ fn (mut p Parser) fn_decl() ast.FnDecl {
 	if p.tok.kind == .lpar {
 		p.next() // (
 		is_method = true
-		is_shared := p.tok.kind in [.key_shared, .key_rwshared]
+		is_shared := p.tok.kind == .key_shared
-		is_atomic_or_rw := p.tok.kind in [.key_rwshared, .key_atomic]
+		is_atomic := p.tok.kind == .key_atomic
-		rec_mut = p.tok.kind == .key_mut || is_shared || is_atomic_or_rw
+		rec_mut = p.tok.kind == .key_mut || is_shared || is_atomic
 		if rec_mut {
 			p.next() // `mut`
 		}
@@ -179,8 +179,8 @@ fn (mut p Parser) fn_decl() ast.FnDecl {
 		if is_shared {
 			rec_type = rec_type.set_flag(.shared_f)
 		}
-		if is_atomic_or_rw {
+		if is_atomic {
-			rec_type = rec_type.set_flag(.atomic_or_rw)
+			rec_type = rec_type.set_flag(.atomic_f)
 		}
 		args << table.Arg{
 			name: rec_name
@@ -400,9 +400,9 @@ fn (mut p Parser) fn_args() ([]table.Arg, bool, bool) {
 		mut arg_no := 1
 		for p.tok.kind != .rpar {
 			arg_name := 'arg_$arg_no'
-			is_shared := p.tok.kind in [.key_shared, .key_rwshared]
+			is_shared := p.tok.kind == .key_shared
-			is_atomic_or_rw := p.tok.kind in [.key_rwshared, .key_atomic]
+			is_atomic := p.tok.kind == .key_atomic
-			is_mut := p.tok.kind == .key_mut || is_shared || is_atomic_or_rw
+			is_mut := p.tok.kind == .key_mut || is_shared || is_atomic
 			if is_mut {
 				p.next()
 			}
@@ -416,13 +416,13 @@ fn (mut p Parser) fn_args() ([]table.Arg, bool, bool) {
 				if !arg_type.has_flag(.generic) {
 					if is_shared {
 						p.check_fn_shared_arguments(arg_type, pos)
-					} else if is_atomic_or_rw {
+					} else if is_atomic {
 						p.check_fn_atomic_arguments(arg_type, pos)
 					} else {
 						p.check_fn_mutable_arguments(arg_type, pos)
 					}
-				} else if is_shared || is_atomic_or_rw {
+				} else if is_shared || is_atomic {
-					p.error_with_pos('generic object cannot be `atomic`, `shared` or `rwshared`', pos)
+					p.error_with_pos('generic object cannot be `atomic`or `shared`', pos)
 				}
 				// if arg_type.is_ptr() {
 				// p.error('cannot mut')
@@ -432,8 +432,8 @@ fn (mut p Parser) fn_args() ([]table.Arg, bool, bool) {
 				if is_shared {
 					arg_type = arg_type.set_flag(.shared_f)
 				}
-				if is_atomic_or_rw {
+				if is_atomic {
-					arg_type = arg_type.set_flag(.atomic_or_rw)
+					arg_type = arg_type.set_flag(.atomic_f)
 				}
 			}
 			if is_variadic {
@@ -456,9 +456,9 @@ fn (mut p Parser) fn_args() ([]table.Arg, bool, bool) {
 		}
 	} else {
 		for p.tok.kind != .rpar {
-			is_shared := p.tok.kind in [.key_shared, .key_rwshared]
+			is_shared := p.tok.kind == .key_shared
-			is_atomic_or_rw := p.tok.kind in [.key_rwshared, .key_atomic]
+			is_atomic := p.tok.kind == .key_atomic
-			mut is_mut := p.tok.kind == .key_mut || is_shared || is_atomic_or_rw
+			mut is_mut := p.tok.kind == .key_mut || is_shared || is_atomic
 			if is_mut {
 				p.next()
 			}
@@ -485,20 +485,20 @@ fn (mut p Parser) fn_args() ([]table.Arg, bool, bool) {
 				if !typ.has_flag(.generic) {
 					if is_shared {
 						p.check_fn_shared_arguments(typ, pos)
-					} else if is_atomic_or_rw {
+					} else if is_atomic {
 						p.check_fn_atomic_arguments(typ, pos)
 					} else {
 						p.check_fn_mutable_arguments(typ, pos)
 					}
-				} else if is_shared || is_atomic_or_rw {
+				} else if is_shared || is_atomic {
-					p.error_with_pos('generic object cannot be `atomic`, `shared` or `rwshared`', pos)
+					p.error_with_pos('generic object cannot be `atomic` or `shared`', pos)
 				}
 				typ = typ.set_nr_muls(1)
 				if is_shared {
 					typ = typ.set_flag(.shared_f)
 				}
-				if is_atomic_or_rw {
+				if is_atomic {
-					typ = typ.set_flag(.atomic_or_rw)
+					typ = typ.set_flag(.atomic_f)
 				}
 			}
 			if is_variadic {

vlib/v/parser/parse_type.v

@@ -133,11 +133,11 @@ pub fn (mut p Parser) parse_type() table.Type {
 			return typ
 		}
 	}
-	is_shared := p.tok.kind in [.key_shared, .key_rwshared]
+	is_shared := p.tok.kind == .key_shared
-	is_atomic_or_rw := p.tok.kind in [.key_rwshared, .key_atomic]
+	is_atomic := p.tok.kind == .key_atomic
 
 	mut nr_muls := 0
-	if p.tok.kind == .key_mut || is_shared || is_atomic_or_rw {
+	if p.tok.kind == .key_mut || is_shared || is_atomic {
 		nr_muls++
 		p.next()
 	}
@@ -161,8 +161,8 @@ pub fn (mut p Parser) parse_type() table.Type {
 	if is_shared {
 		typ = typ.set_flag(.shared_f)
 	}
-	if is_atomic_or_rw {
+	if is_atomic {
-		typ = typ.set_flag(.atomic_or_rw)
+		typ = typ.set_flag(.atomic_f)
 	}
 	if nr_muls > 0 {
 		typ = typ.set_nr_muls(nr_muls)

vlib/v/parser/parser.v

@@ -514,7 +514,7 @@ pub fn (mut p Parser) stmt(is_top_level bool) ast.Stmt {
 		.key_for {
 			return p.for_stmt()
 		}
-		.name, .key_mut, .key_shared, .key_atomic, .key_rwshared, .key_static, .mul {
+		.name, .key_mut, .key_shared, .key_atomic, .key_static, .mul {
 			if p.tok.kind == .name {
 				if p.tok.lit == 'sql' {
 					return p.sql_stmt()
@@ -783,9 +783,9 @@ fn (mut p Parser) parse_multi_expr(is_top_level bool) ast.Stmt {
 
 pub fn (mut p Parser) parse_ident(language table.Language) ast.Ident {
 	// p.warn('name ')
-	is_shared := p.tok.kind in [.key_shared, .key_rwshared]
+	is_shared := p.tok.kind == .key_shared
-	is_atomic_or_rw := p.tok.kind in [.key_rwshared, .key_atomic]
+	is_atomic := p.tok.kind == .key_atomic
-	is_mut := p.tok.kind == .key_mut || is_shared || is_atomic_or_rw
+	is_mut := p.tok.kind == .key_mut || is_shared || is_atomic
 	if is_mut {
 		p.next()
 	}
@@ -823,7 +823,7 @@ pub fn (mut p Parser) parse_ident(language table.Language) ast.Ident {
 			info: ast.IdentVar{
 				is_mut: is_mut
 				is_static: is_static
-				share: table.sharetype_from_flags(is_shared, is_atomic_or_rw)
+				share: table.sharetype_from_flags(is_shared, is_atomic)
 			}
 		}
 	} else {

vlib/v/parser/pratt.v

@@ -16,7 +16,7 @@ pub fn (mut p Parser) expr(precedence int) ast.Expr {
 	p.eat_comments()
 	// Prefix
 	match p.tok.kind {
-		.key_mut, .key_shared, .key_rwshared, .key_atomic, .key_static {
+		.key_mut, .key_shared, .key_atomic, .key_static {
 			node = p.name_expr()
 			p.is_stmt_ident = is_stmt_ident
 		}

vlib/v/table/atypes.v

@@ -42,7 +42,7 @@ pub enum TypeFlag {
 	variadic
 	generic
 	shared_f
-	atomic_or_rw
+	atomic_f
 }
 
 /* 
@@ -54,7 +54,6 @@ pub enum ShareType {
 	mut_t
 	shared_t
 	atomic_t
-	rwshared_t
 }
 
 pub fn (t ShareType) str() string {
@@ -62,7 +61,6 @@ pub fn (t ShareType) str() string {
 		.mut_t { return 'mut' }
 		.shared_t { return 'shared' }
 		.atomic_t { return 'atomic' }
-		.rwshared_t { return 'rwshared' }
 	}
 }
 
@@ -78,12 +76,12 @@ pub fn (t Type) atomic_typename() string {
 	}
 }
 
-pub fn sharetype_from_flags(is_shared, is_atomic_or_rw bool) ShareType {
+pub fn sharetype_from_flags(is_shared, is_atomic bool) ShareType {
-	return ShareType((int(is_atomic_or_rw) << 1) | int(is_shared))
+	return ShareType((int(is_atomic) << 1) | int(is_shared))
 }
 
 pub fn (t Type) share() ShareType {
-	return sharetype_from_flags(t.has_flag(.shared_f), t.has_flag(.atomic_or_rw))
+	return sharetype_from_flags(t.has_flag(.shared_f), t.has_flag(.atomic_f))
 }
 
 pub fn (types []Type) contains(typ Type) bool {

vlib/v/tests/shared_lock_3_test.v

@@ -6,7 +6,7 @@ mut:
 	a int
 }
 
-fn f(rwshared x St, shared z St) {
+fn f(shared x St, shared z St) {
 	for _ in 0..reads_per_thread {
 		rlock x { // other instances may read at the same time
 			time.sleep_ms(1)
@@ -26,14 +26,14 @@ const (
 
 fn test_shared_lock() {
 	// object with separate read/write lock
-	rwshared x := &St{
+	shared x := &St{
 		a: 5
 	}
 	shared z := &St{
 		a: read_threads
 	}
 	for _ in 0..read_threads {
-		go f(rwshared x, shared z)
+		go f(shared x, shared z)
 	}
 	for i in 0..writes {
 		lock x { // wait for ongoing reads to finish, don't start new ones

vlib/v/tests/shared_lock_4_test.v

@@ -6,7 +6,7 @@ mut:
 	a int
 }
 
-fn (rwshared x St) f(shared z St) {
+fn (shared x St) f(shared z St) {
 	for _ in 0..reads_per_thread {
 		rlock x { // other instances may read at the same time
 			time.sleep_ms(1)
@@ -26,7 +26,7 @@ const (
 
 fn test_shared_lock() {
 	// object with separate read/write lock
-	rwshared x := &St{
+	shared x := &St{
 		a: 5
 	}
 	shared z := &St{

vlib/v/token/token.v

@@ -109,7 +109,6 @@ pub enum Kind {
 	key_module
 	key_mut
 	key_shared
-	key_rwshared
 	key_lock
 	key_rlock
 	key_none
@@ -231,7 +230,6 @@ fn build_token_str() []string {
 	s[Kind.key_const] = 'const'
 	s[Kind.key_mut] = 'mut'
 	s[Kind.key_shared] = 'shared'
-	s[Kind.key_rwshared] = 'rwshared'
 	s[Kind.key_lock] = 'lock'
 	s[Kind.key_rlock] = 'rlock'
 	s[Kind.key_type] = 'type'