Commit 0a88352689

@@ -20,7 +20,7 @@ pub const File = struct {
     /// or, more specifically, whether the I/O is blocking.
     io_mode: io.Mode,
 
-    /// Even when std.io.mode is async, it is still sometimes desirable to perform blocking I/O, although
+    /// Even when 'std.io.mode' is async, it is still sometimes desirable to perform blocking I/O, although
     /// not by default. For example, when printing a stack trace to stderr.
     async_block_allowed: @TypeOf(async_block_allowed_no) = async_block_allowed_no,
 
@@ -40,6 +40,11 @@ pub const File = struct {
     pub const OpenFlags = struct {
         read: bool = true,
         write: bool = false,
+
+        /// This prevents `O_NONBLOCK` from being passed even if `std.io.is_async`.
+        /// It allows the use of `noasync` when calling functions related to opening
+        /// the file, reading, and writing.
+        always_blocking: bool = false,
     };
 
     /// TODO https://github.com/ziglang/zig/issues/3802

@@ -811,22 +811,22 @@ pub fn openElfDebugInfo(allocator: *mem.Allocator, elf_file_path: []const u8) !M
     const mapped_mem = try mapWholeFile(elf_file_path);
 
     var seekable_stream = io.SliceSeekableInStream.init(mapped_mem);
-    var efile = try elf.Elf.openStream(
+    var efile = try noasync elf.Elf.openStream(
         allocator,
         @ptrCast(*DW.DwarfSeekableStream, &seekable_stream.seekable_stream),
         @ptrCast(*DW.DwarfInStream, &seekable_stream.stream),
     );
-    defer efile.close();
+    defer noasync efile.close();
 
-    const debug_info = (try efile.findSection(".debug_info")) orelse
+    const debug_info = (try noasync efile.findSection(".debug_info")) orelse
         return error.MissingDebugInfo;
-    const debug_abbrev = (try efile.findSection(".debug_abbrev")) orelse
+    const debug_abbrev = (try noasync efile.findSection(".debug_abbrev")) orelse
         return error.MissingDebugInfo;
-    const debug_str = (try efile.findSection(".debug_str")) orelse
+    const debug_str = (try noasync efile.findSection(".debug_str")) orelse
         return error.MissingDebugInfo;
-    const debug_line = (try efile.findSection(".debug_line")) orelse
+    const debug_line = (try noasync efile.findSection(".debug_line")) orelse
         return error.MissingDebugInfo;
-    const opt_debug_ranges = try efile.findSection(".debug_ranges");
+    const opt_debug_ranges = try noasync efile.findSection(".debug_ranges");
 
     var di = DW.DwarfInfo{
         .endian = efile.endian,
@@ -840,7 +840,7 @@ pub fn openElfDebugInfo(allocator: *mem.Allocator, elf_file_path: []const u8) !M
             null,
     };
 
-    try DW.openDwarfDebugInfo(&di, allocator);
+    try noasync DW.openDwarfDebugInfo(&di, allocator);
 
     return ModuleDebugInfo{
         .base_address = undefined,
@@ -983,8 +983,8 @@ const MachoSymbol = struct {
 };
 
 fn mapWholeFile(path: []const u8) ![]const u8 {
-    const file = try fs.openFileAbsolute(path, .{});
-    defer file.close();
+    const file = try noasync fs.openFileAbsolute(path, .{ .always_blocking = true });
+    defer noasync file.close();
 
     const file_len = try math.cast(usize, try file.getEndPos());
     const mapped_mem = try os.mmap(
@@ -1565,14 +1565,14 @@ pub const ModuleDebugInfo = switch (builtin.os) {
             // Translate the VA into an address into this object
             const relocated_address = address - self.base_address;
 
-            if (self.dwarf.findCompileUnit(relocated_address)) |compile_unit| {
+            if (noasync self.dwarf.findCompileUnit(relocated_address)) |compile_unit| {
                 return SymbolInfo{
-                    .symbol_name = self.dwarf.getSymbolName(relocated_address) orelse "???",
+                    .symbol_name = noasync self.dwarf.getSymbolName(relocated_address) orelse "???",
                     .compile_unit_name = compile_unit.die.getAttrString(&self.dwarf, DW.AT_name) catch |err| switch (err) {
                         error.MissingDebugInfo, error.InvalidDebugInfo => "???",
                         else => return err,
                     },
-                    .line_info = self.dwarf.getLineNumberInfo(compile_unit.*, relocated_address) catch |err| switch (err) {
+                    .line_info = noasync self.dwarf.getLineNumberInfo(compile_unit.*, relocated_address) catch |err| switch (err) {
                         error.MissingDebugInfo, error.InvalidDebugInfo => null,
                         else => return err,
                     },

@@ -731,11 +731,18 @@ pub const Dir = struct {
             @as(u32, os.O_WRONLY)
         else
             @as(u32, os.O_RDONLY);
-        const fd = if (need_async_thread)
+        const fd = if (need_async_thread and !flags.always_blocking)
             try std.event.Loop.instance.?.openatZ(self.fd, sub_path, os_flags, 0)
         else
             try os.openatC(self.fd, sub_path, os_flags, 0);
-        return File{ .handle = fd, .io_mode = .blocking };
+        return File{
+            .handle = fd,
+            .io_mode = .blocking,
+            .async_block_allowed = if (flags.always_blocking)
+                File.async_block_allowed_yes
+            else
+                File.async_block_allowed_no,
+        };
     }
 
     /// Same as `openFile` but Windows-only and the path parameter is