v3: track final preinclude macro state

Author: medvednikov

vlib/v3/gen/c/cleanc.v

@@ -336,6 +336,7 @@ mut:
 	inlined_c_typedef_names        map[string]bool
 	inlined_c_fns                  map[string]bool
 	inlined_c_declared_fns         map[string]bool
+	inlined_c_active_macros        map[string]bool
 	possibly_active_c_macros       map[string]bool
 	inlined_c_static_fns           map[string]bool
 	cache_omitted_c_fns            map[string]bool
@@ -1029,6 +1030,7 @@ pub fn FlatGen.new() FlatGen {
 		inlined_c_structs:               map[string]bool{}
 		inlined_c_fns:                   map[string]bool{}
 		inlined_c_declared_fns:          map[string]bool{}
+		inlined_c_active_macros:         map[string]bool{}
 		possibly_active_c_macros:        map[string]bool{}
 		inlined_c_static_fns:            map[string]bool{}
 		cache_omitted_c_fns:             map[string]bool{}
@@ -2615,6 +2617,7 @@ pub fn (mut g FlatGen) gen_with_used_options(a &flat.FlatAst, used_fns map[strin
 	g.inlined_c_structs.clear()
 	g.inlined_c_fns.clear()
 	g.inlined_c_declared_fns.clear()
+	g.inlined_c_active_macros.clear()
 	g.possibly_active_c_macros.clear()
 	g.inlined_c_static_fns.clear()
 	g.cache_omitted_c_fns.clear()
@@ -3377,6 +3380,9 @@ fn (mut g FlatGen) cache_user_c_string_symbols() map[string]bool {
 	for name in g.inlined_c_declared_fns.keys() {
 		collect_cache_numbered_string_symbols(name, mut symbols)
 	}
+	for name in g.inlined_c_active_macros.keys() {
+		collect_cache_numbered_string_symbols(name, mut symbols)
+	}
 	referenced_symbols := g.c_extern_referenced_symbols()
 	for name in referenced_symbols.keys() {
 		collect_cache_numbered_string_symbols(name, mut symbols)
@@ -4675,10 +4681,23 @@ fn (mut g FlatGen) collect_preserved_header_file_with_state_and_scope(path strin
 	if collect_declarations {
 		g.collect_inlined_c_structs(final_scan.text)
 		g.collect_inlined_c_fns(final_scan.text)
-		g.collect_inlined_c_declared_fns(final_scan.text)
+		g.collect_inlined_c_declarations(final_scan.text)
+		for macro_name in final_scan.macro_names {
+			if final_scan.final_state.defined[macro_name] {
+				g.inlined_c_active_macros[macro_name] = true
+				g.possibly_active_c_macros.delete(macro_name)
+			} else if final_scan.final_state.undefined[macro_name] {
+				g.inlined_c_active_macros.delete(macro_name)
+				g.possibly_active_c_macros.delete(macro_name)
+			} else {
+				g.inlined_c_active_macros.delete(macro_name)
+				g.possibly_active_c_macros[macro_name] = true
+			}
+		}
 	}
 	for macro_name in final_scan.possibly_active_macro_names {
-		if macro_name !in g.inlined_c_declared_fns {
+		if macro_name !in final_scan.final_state.undefined
+			&& macro_name !in g.inlined_c_active_macros && macro_name !in g.inlined_c_declared_fns {
 			g.possibly_active_c_macros[macro_name] = true
 		}
 	}
@@ -4701,6 +4720,7 @@ struct CHeaderActiveScan {
 	include_keys                []string
 	include_args                []string
 	include_definitely_active   []bool
+	macro_names                 []string
 	possibly_active_macro_names []string
 	final_state                 CHeaderMacroState
 }
@@ -4853,6 +4873,7 @@ fn c_header_definitely_active_scan_with_include_results(text string, state CHead
 	mut include_keys := []string{}
 	mut include_args := []string{}
 	mut include_definitely_active := []bool{}
+	mut macro_names := map[string]bool{}
 	mut possibly_active_macro_names := map[string]bool{}
 	mut output := strings.new_builder(text.len)
 	mut in_block_comment := false
@@ -4950,6 +4971,9 @@ fn c_header_definitely_active_scan_with_include_results(text string, state CHead
 			parts := c_directive_arg(clean).fields()
 			if parts.len > 0 {
 				macro_name := parts[0].all_before('(')
+				if possibly_active && macro_name.len > 0 {
+					macro_names[macro_name] = true
+				}
 				if name == 'define' && possibly_active && macro_name.len > 0 {
 					possibly_active_macro_names[macro_name] = true
 				}
@@ -5010,6 +5034,7 @@ fn c_header_definitely_active_scan_with_include_results(text string, state CHead
 		include_keys:                include_keys
 		include_args:                include_args
 		include_definitely_active:   include_definitely_active
+		macro_names:                 macro_names.keys()
 		possibly_active_macro_names: possibly_active_macro_names.keys()
 		final_state:                 CHeaderMacroState{
 			defined:                  defined
@@ -8103,6 +8128,27 @@ fn c_strip_comments(text string) string {
 }
 
 fn (mut g FlatGen) collect_inlined_c_declared_fns(text string) {
+	g.collect_inlined_c_declarations(text)
+	// Inlined source text has not gone through the active-branch scanner. Keep
+	// every visible definition conservative, as before; only preserved headers
+	// can use their final preprocessor state to prove that a later #undef wins.
+	for line in c_strip_comments(text).split_into_lines() {
+		clean := line.trim_space()
+		if clean.len == 0 || clean[0] != `#` || c_directive_name(clean) != 'define' {
+			continue
+		}
+		arg := c_directive_arg(clean)
+		mut name_end := 0
+		for name_end < arg.len && c_ident_char(arg[name_end]) {
+			name_end++
+		}
+		if name_end > 0 {
+			g.inlined_c_active_macros[arg[..name_end]] = true
+		}
+	}
+}
+
+fn (mut g FlatGen) collect_inlined_c_declarations(text string) {
 	// Header declarations often span several lines (one parameter per line);
 	// accumulate a pending declaration until its terminating `;` so those are
 	// collected too, not just single-line prototypes.
@@ -8112,19 +8158,6 @@ fn (mut g FlatGen) collect_inlined_c_declared_fns(text string) {
 		for name in c_macro_declared_fn_names(clean) {
 			g.inlined_c_declared_fns[name] = true
 		}
-		if clean.len > 0 && clean[0] == `#` && c_directive_name(clean) == 'define' {
-			// Any macro (object- or function-like) named like a `fn C.x` makes
-			// an emitted extern prototype wrong after preprocessing; the
-			// header's definition is authoritative.
-			arg := c_directive_arg(clean)
-			mut name_end := 0
-			for name_end < arg.len && c_ident_char(arg[name_end]) {
-				name_end++
-			}
-			if name_end > 0 {
-				g.inlined_c_declared_fns[arg[..name_end]] = true
-			}
-		}
 		if pending.len > 0 {
 			if clean.len == 0 || clean[0] == `#` || clean.contains('{') || clean.contains('}')
 				|| pending.len > 4096 {

vlib/v3/gen/c/fn.v

@@ -15140,12 +15140,13 @@ fn (g &FlatGen) should_emit_c_extern_decl(cfn string) bool {
 		return false
 	}
 	if cfn in g.inlined_c_fns {
-		if g.cache_split && cfn in g.cache_omitted_c_fns && cfn !in g.inlined_c_declared_fns {
+		if g.cache_split && cfn in g.cache_omitted_c_fns && cfn !in g.inlined_c_declared_fns
+			&& cfn !in g.inlined_c_active_macros {
 			return true
 		}
 		return false
 	}
-	if cfn in g.inlined_c_declared_fns {
+	if cfn in g.inlined_c_declared_fns || cfn in g.inlined_c_active_macros {
 		return false
 	}
 	return true
@@ -15248,7 +15249,7 @@ const c_manual_stdlib_declared_fns = {
 
 fn (g &FlatGen) c_extern_decl_is_cached_object_fallback(cfn string) bool {
 	return g.cache_split && cfn in g.inlined_c_fns && cfn in g.cache_omitted_c_fns
-		&& cfn !in g.inlined_c_declared_fns
+		&& cfn !in g.inlined_c_declared_fns && cfn !in g.inlined_c_active_macros
 }
 
 fn (g &FlatGen) should_emit_c_extern_decl_from_file(cfn string, source_file string) bool {

vlib/v3/gen/c/source_directive_test.v

@@ -133,7 +133,7 @@ fn test_preinclude_carries_macro_state_to_later_preincludes() {
 		typ:   '"${api_header}"'
 	}, source, false)
 
-	assert 'chained_api' in g.inlined_c_declared_fns
+	assert 'chained_api' in g.inlined_c_active_macros
 	assert g.preinclude_directives == ['#include "${config_header}"', '#include "${api_header}"']
 }
 
@@ -187,7 +187,7 @@ fn test_preserved_header_carries_child_macros_into_parent_remainder() {
 	mut g := FlatGen.new()
 	g.collect_preserved_header_file(parent, [root])
 
-	assert 'enabled_api' in g.inlined_c_declared_fns
+	assert 'enabled_api' in g.inlined_c_active_macros
 }
 
 fn test_preserved_unguarded_header_is_rescanned_under_new_macro_state() {
@@ -205,7 +205,7 @@ fn test_preserved_unguarded_header_is_rescanned_under_new_macro_state() {
 	mut g := FlatGen.new()
 	g.collect_preserved_header_file(parent, [root])
 
-	assert 'enabled_api' in g.inlined_c_declared_fns
+	assert 'enabled_api' in g.inlined_c_active_macros
 	child_prefix := os.real_path(child) + '\n'
 	assert g.preserved_header_scan_results.keys().filter(it.starts_with(child_prefix)).len >= 2
 }
@@ -226,7 +226,7 @@ fn test_preserved_header_passes_definite_parent_macro_state_to_children() {
 	mut g := FlatGen.new()
 	g.collect_preserved_header_file(parent, [root])
 
-	assert 'enabled_api' in g.inlined_c_declared_fns
+	assert 'enabled_api' in g.inlined_c_active_macros
 	assert 'omitted_api' !in g.inlined_c_declared_fns
 }
 
@@ -279,6 +279,33 @@ fn test_preserved_header_guards_externs_for_possibly_active_function_macros() {
 	assert 'inactive_api' !in g.possibly_active_c_macros
 }
 
+fn test_preserved_headers_track_final_macro_state_for_externs() {
+	root := os.join_path(os.vtmp_dir(), 'v3_preserved_final_macro_${os.getpid()}')
+	os.rmdir_all(root) or {}
+	os.mkdir_all(root)!
+	defer {
+		os.rmdir_all(root) or {}
+	}
+	first := os.join_path(root, 'first.h')
+	second := os.join_path(root, 'second.h')
+	os.write_file(first,
+		'#define same_header_api(x) ((x) + 1)\n#undef same_header_api\n#define declared_api(x) ((x) + 2)\n#undef declared_api\nint declared_api(void);\n#define later_header_api(x) ((x) + 3)\n')!
+	os.write_file(second, '#undef later_header_api\n')!
+
+	mut g := FlatGen.new()
+	state := g.collect_preserved_header_file_with_state(first, [root], CHeaderMacroState{})
+	assert 'same_header_api' !in g.inlined_c_active_macros
+	assert 'later_header_api' in g.inlined_c_active_macros
+	assert 'declared_api' in g.inlined_c_declared_fns
+	assert g.should_emit_c_extern_decl('same_header_api')
+	assert !g.should_emit_c_extern_decl('later_header_api')
+	assert !g.should_emit_c_extern_decl('declared_api')
+	g.collect_preserved_header_file_with_state(second, [root], state)
+	assert 'later_header_api' !in g.inlined_c_active_macros
+	assert g.should_emit_c_extern_decl('later_header_api')
+	assert !g.should_emit_c_extern_decl('declared_api')
+}
+
 fn test_preserved_header_scans_includes_in_possibly_active_branches_for_macros() {
 	root := os.join_path(os.vtmp_dir(), 'v3_preserved_possible_include_${os.getpid()}')
 	os.rmdir_all(root) or {}