all: add OS-specific headers support for #include directives (#26654) (fixes #26562)

Author: medvednikov

vlib/v/ast/ast.v

@@ -1504,7 +1504,8 @@ pub mut:
 	msg      string // : 'please install openssl'
 	ct_conds []Expr // *all* comptime conditions, that must be true, for the hash to be processed
 	// ct_conds is filled by the checker, based on the current nesting of `$if cond1 {}` blocks
-	attrs []Attr
+	ct_low_level_cond string // optional low-level comptime condition e.g. 'linux', 'darwin' for `#include linux <pty.h>`
+	attrs             []Attr
 }
 
 // variable assign statement

vlib/v/checker/checker.v

@@ -2950,6 +2950,11 @@ fn (mut c Checker) hash_stmt(mut node ast.HashStmt) {
 	if c.ct_cond_stack.len > 0 {
 		node.ct_conds = c.ct_cond_stack.clone()
 	}
+	if node.ct_low_level_cond.len > 0
+		&& node.ct_low_level_cond !in ast.valid_comptime_not_user_defined {
+		c.error('invalid OS/platform condition `${node.ct_low_level_cond}` in #${node.kind}',
+			node.pos)
+	}
 	if c.pref.backend == .golang || c.is_js_backend {
 		// consider the best way to handle the .go.vv files
 		if !c.file.path.ends_with('.js.v') && !c.file.path.ends_with('.go.v')

vlib/v/gen/c/cgen.v

@@ -6214,6 +6214,16 @@ fn (mut g Gen) gen_hash_stmts(mut sb strings.Builder, node &ast.HashStmtNode, se
 			if !need_gen_stmt {
 				return
 			}
+			// OS-specific condition e.g. `#include linux <pty.h>` wraps the output with #if / #endif
+			has_low_level_cond := node.ct_low_level_cond.len > 0
+			if has_low_level_cond {
+				ifdef := ast.comptime_if_to_ifdef(node.ct_low_level_cond, g.pref) or {
+					g.error('#${node.kind} has invalid condition `${node.ct_low_level_cond}`',
+						node.pos)
+					return
+				}
+				sb.writeln('\n#if defined(${ifdef})')
+			}
 			line_nr := node.pos.line_nr + 1
 			match node.kind {
 				'include', 'preinclude', 'postinclude' {
@@ -6233,6 +6243,9 @@ fn (mut g Gen) gen_hash_stmts(mut sb strings.Builder, node &ast.HashStmtNode, se
 				}
 				else {}
 			}
+			if has_low_level_cond {
+				sb.writeln('#endif')
+			}
 		}
 		// TODO: support $match
 	}

vlib/v/gen/c/testdata/os_specific_hash_stmts.c.must_have

@@ -0,0 +1,12 @@
+#if defined(__linux__)
+#include <pty.h>
+#endif
+#if defined(__DARWIN__)
+#include <util.h>
+#endif
+#if defined(_WIN32)
+#include "win_header.h"
+#endif
+#if defined(__FreeBSD__)
+#include <libutil.h>
+#endif

vlib/v/gen/c/testdata/os_specific_hash_stmts.vv

@@ -0,0 +1,10 @@
+// vtest vflags: -os cross
+module main
+
+#include linux <pty.h>
+#include darwin <util.h>
+#include windows "win_header.h"
+#include freebsd <libutil.h>
+
+fn main() {
+}

vlib/v/gen/native/comptime.v

@@ -15,6 +15,11 @@ fn (mut g Gen) comptime_conditional(node ast.IfExpr) ?ast.IfBranch {
 }
 
 fn (mut g Gen) should_emit_hash_stmt(node ast.HashStmt) bool {
+	if node.ct_low_level_cond.len > 0 {
+		if !g.comptime_ident(node.ct_low_level_cond, false) {
+			return false
+		}
+	}
 	return node.ct_conds.all(g.comptime_is_truthy(it))
 }
 

vlib/v/parser/comptime.v

@@ -93,6 +93,7 @@ fn (mut p Parser) hash() ast.HashStmt {
 	p.next()
 	mut main_str := ''
 	mut msg := ''
+	mut ct_low_level_cond := ''
 	content := val.all_after('${kind} ').all_before('//')
 	if content.contains(' #') {
 		main_str = content.all_before(' #').trim_space()
@@ -102,6 +103,19 @@ fn (mut p Parser) hash() ast.HashStmt {
 		msg = ''
 	}
 
+	// Detect OS-specific conditions like `#include linux <pty.h>` or `#include darwin "util.h"`.
+	// The condition is the first word before the actual include path.
+	if kind in ['include', 'preinclude', 'postinclude', 'insert'] {
+		first_space := main_str.index_u8(` `)
+		if first_space > 0 {
+			maybe_cond := main_str[..first_space]
+			if maybe_cond in ast.valid_comptime_not_user_defined {
+				ct_low_level_cond = maybe_cond
+				main_str = main_str[first_space + 1..].trim_space()
+			}
+		}
+	}
+
 	mut is_use_once := false
 	for fna in attrs {
 		match fna.name {
@@ -111,15 +125,16 @@ fn (mut p Parser) hash() ast.HashStmt {
 	}
 
 	return ast.HashStmt{
-		mod:         p.mod
-		source_file: p.file_path
-		val:         val
-		kind:        kind
-		main:        main_str
-		msg:         msg
-		pos:         pos
-		attrs:       attrs
-		is_use_once: is_use_once
+		mod:               p.mod
+		source_file:       p.file_path
+		val:               val
+		kind:              kind
+		main:              main_str
+		msg:               msg
+		pos:               pos
+		attrs:             attrs
+		is_use_once:       is_use_once
+		ct_low_level_cond: ct_low_level_cond
 	}
 }
 

vlib/v2/ast/ast.v

@@ -810,8 +810,9 @@ pub:
 // #flag / #include
 pub struct Directive {
 pub:
-	name  string
-	value string
+	name    string
+	value   string
+	ct_cond string // optional comptime condition e.g. 'linux', 'darwin' for `#include linux <pty.h>`
 }
 
 pub struct EnumDecl {

vlib/v2/ast_dump/ast_dump.v

@@ -404,6 +404,12 @@ fn (mut jb JsonBuilder) write_directive(stmt ast.Directive) {
 	jb.write_indent()
 	jb.sb.write_string('"value": ')
 	jb.write_string(stmt.value)
+	if stmt.ct_cond.len > 0 {
+		jb.sb.write_string(',\n')
+		jb.write_indent()
+		jb.sb.write_string('"ct_cond": ')
+		jb.write_string(stmt.ct_cond)
+	}
 	jb.sb.write_string('\n')
 
 	jb.indent--

vlib/v2/gen/cleanc/stmt.v

@@ -287,7 +287,8 @@ fn (mut g Gen) gen_stmt(node ast.Stmt) {
 		}
 		ast.Directive {
 			g.write_indent()
-			g.sb.writeln('/* [TODO] Directive: #${node.name} ${node.value} */')
+			ct_cond_str := if node.ct_cond.len > 0 { ' ct_cond=${node.ct_cond}' } else { '' }
+			g.sb.writeln('/* [TODO] Directive: #${node.name} ${node.value}${ct_cond_str} */')
 		}
 		ast.ForInStmt {
 			panic('bug in v2 compiler: ForInStmt should have been lowered in v2.transformer')