checker,pref: fix $if wasm32_emscripten { check, add tests (vlang#2…

…2816)

vlib/v/ast/comptime_valid_idents.v

@@ -2,15 +2,14 @@ module ast
 
 pub const valid_comptime_if_os = ['windows', 'ios', 'macos', 'mach', 'darwin', 'hpux', 'gnu', 'qnx',
 	'linux', 'freebsd', 'openbsd', 'netbsd', 'bsd', 'dragonfly', 'android', 'termux', 'solaris',
-	'haiku', 'serenity', 'vinix', 'plan9']
+	'haiku', 'serenity', 'vinix', 'plan9', 'wasm32_emscripten']
 pub const valid_comptime_if_compilers = ['gcc', 'tinyc', 'clang', 'mingw', 'msvc', 'cplusplus']
 pub const valid_comptime_if_platforms = ['amd64', 'i386', 'aarch64', 'arm64', 'arm32', 'rv64',
 	'rv32']
 pub const valid_comptime_if_cpu_features = ['x64', 'x32', 'little_endian', 'big_endian']
 pub const valid_comptime_if_other = ['apk', 'js', 'debug', 'prod', 'test', 'glibc', 'prealloc',
 	'no_bounds_checking', 'freestanding', 'threads', 'js_node', 'js_browser', 'js_freestanding',
-	'interpreter', 'es5', 'profile', 'wasm32', 'wasm32_emscripten', 'wasm32_wasi', 'fast_math',
-	'native', 'autofree']
+	'interpreter', 'es5', 'profile', 'wasm32', 'wasm32_wasi', 'fast_math', 'native', 'autofree']
 pub const valid_comptime_not_user_defined = all_valid_comptime_idents()
 pub const valid_comptime_compression_types = ['none', 'zlib']
 

vlib/v/checker/comptime.v

@@ -895,12 +895,18 @@ fn (mut c Checker) comptime_if_cond(mut cond ast.Expr, pos token.Pos) ComptimeBr
 			is_user_ident = false
 			ident_name = cname
 			if cname in ast.valid_comptime_if_os {
-				mut is_os_target_equal := true
+				mut ident_result := ComptimeBranchSkipState.skip
 				if !c.pref.output_cross_c {
-					target_os := c.pref.os.str().to_lower_ascii()
-					is_os_target_equal = cname == target_os
+					if cname_enum_val := pref.os_from_string(cname) {
+						if cname_enum_val == c.pref.os {
+							ident_result = .eval
+						}
+					}
+				}
+				$if trace_comptime_os_checks ? {
+					eprintln('>>> ident_name: ${ident_name} | c.pref.os: ${c.pref.os} | ident_result: ${ident_result}')
 				}
-				return if is_os_target_equal { .eval } else { .skip }
+				return ident_result
 			} else if cname in ast.valid_comptime_if_compilers {
 				return if pref.cc_from_string(cname) == c.pref.ccompiler_type {
 					.eval

vlib/v/gen/c/testdata/platform_wrapper/file_default.c.v

@@ -0,0 +1,5 @@
+module platform_wrapper
+
+pub fn abc() int {
+	return 987654321
+}

vlib/v/gen/c/testdata/platform_wrapper/file_linux.c.v

@@ -0,0 +1,10 @@
+module platform_wrapper
+
+pub fn abc() int {
+	return 987654321
+}
+
+pub fn fn_defined_on_linux() int {
+	// println('hi from ${@FN}, in file_linux.c.v')
+	return 456
+}

vlib/v/gen/c/testdata/platform_wrapper/file_macos.c.v

@@ -0,0 +1,10 @@
+module platform_wrapper
+
+pub fn abc() int {
+	return 987654321
+}
+
+pub fn fn_defined_on_macos() int {
+	// println('hi from ${@FN}, in file_macos.c.v')
+	return 789
+}

vlib/v/gen/c/testdata/platform_wrapper/file_wasm32_emscripten.c.v

@@ -0,0 +1,10 @@
+module platform_wrapper
+
+pub fn abc() int {
+	return 987654321
+}
+
+pub fn fn_defined_in_wasm32_emscripten() int {
+	println('hi from ${@FN}, defined in file_wasm32_emscripten.c.v')
+	return 12345
+}

vlib/v/gen/c/testdata/platform_wrapper/file_windows.c.v

@@ -0,0 +1,10 @@
+module platform_wrapper
+
+pub fn abc() int {
+	return 987654321
+}
+
+pub fn fn_defined_on_windows() int {
+	// println('hi from ${@FN}, in file_windows.c.v')
+	return 123
+}

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

@@ -0,0 +1,9 @@
+#if defined(CUSTOM_DEFINE_emscripten)
+println(_SLIT("> inside then branch of if emscripten"));
+
+#if defined(__EMSCRIPTEN__)
+println(_SLIT("> inside then branch of if wasm32_emscripten"));
+
+v__gen__c__testdata__platform_wrapper__fn_defined_in_wasm32_emscripten();
+
+v__gen__c__testdata__platform_wrapper__abc();

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

@@ -0,0 +1,35 @@
+module main
+
+// vtest vflags: -os wasm32_emscripten
+
+import platform_wrapper
+
+fn main() {
+	println('start')
+	$if windows {
+		assert platform_wrapper.fn_defined_on_windows() == 123
+	}
+	$if linux {
+		assert platform_wrapper.fn_defined_on_linux() == 456
+	}
+	$if macos {
+		assert platform_wrapper.fn_defined_on_macos() == 789
+	}
+	println('--- 1')
+	$if emscripten ? {
+		println('> inside then branch of if emscripten')
+		assert platform_wrapper.fn_defined_in_wasm32_emscripten() == 12345
+	} $else {
+		println('> inside else branch of if emscripten')
+	}
+	println('--- 2')
+	$if wasm32_emscripten {
+		println('> inside then branch of if wasm32_emscripten')
+		assert platform_wrapper.fn_defined_in_wasm32_emscripten() == 12345
+	} $else {
+		println('> inside else branch of if wasm32_emscripten')
+	}
+	println('--- 3')
+	platform_wrapper.abc()
+	println('done')
+}

vlib/v/gen/c/testdata/platform_wrapper_non_emscripten.out

@@ -0,0 +1,7 @@
+start
+--- 1
+> inside else branch of if emscripten
+--- 2
+> inside else branch of if wasm32_emscripten
+--- 3
+done

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

@@ -0,0 +1,33 @@
+module main
+
+import platform_wrapper
+
+fn main() {
+	println('start')
+	$if windows {
+		assert platform_wrapper.fn_defined_on_windows() == 123
+	}
+	$if linux {
+		assert platform_wrapper.fn_defined_on_linux() == 456
+	}
+	$if macos {
+		assert platform_wrapper.fn_defined_on_macos() == 789
+	}
+	println('--- 1')
+	$if emscripten ? {
+		println('> inside then branch of if emscripten')
+		assert platform_wrapper.fn_defined_in_wasm32_emscripten() == 12345
+	} $else {
+		println('> inside else branch of if emscripten')
+	}
+	println('--- 2')
+	$if wasm32_emscripten {
+		println('> inside then branch of if wasm32_emscripten')
+		assert platform_wrapper.fn_defined_in_wasm32_emscripten() == 12345
+	} $else {
+		println('> inside else branch of if wasm32_emscripten')
+	}
+	println('--- 3')
+	platform_wrapper.abc()
+	println('done')
+}

vlib/v/pref/os.v

@@ -132,6 +132,12 @@ pub fn os_from_string(os_str string) !OS {
 }
 
 pub fn (o OS) str() string {
+	// TODO: check more thoroughly, why this method needs to exist at all,
+	// and why should it override the default autogenerated .str() method,
+	// instead of being named something like .label() ...
+	// It seems to serve only display purposes on the surface, but it is used
+	// internally by the compiler for comptime comparisons, which seems very
+	// error prone. It bugged the interpretation of `$if wasm32_emscripten {` for example.
 	match o {
 		._auto { return 'RESERVED: AUTO' }
 		.ios { return 'iOS' }
@@ -173,10 +179,9 @@ pub fn get_host_os() OS {
 	$if emscripten ? {
 		return .wasm32_emscripten
 	}
-	// TODO: make this work:
-	// $if wasm32_emscripten {
-	// 	return .wasm32_emscripten
-	// }
+	$if wasm32_emscripten {
+		return .wasm32_emscripten
+	}
 	$if linux {
 		return .linux
 	}