Commit 0ae2ea671b

@@ -990,6 +990,8 @@ pub const File = struct {
         return index;
     }
 
+    /// On Windows, this function currently does alter the file pointer.
+    /// https://github.com/ziglang/zig/issues/12783
     pub fn pread(self: File, buffer: []u8, offset: u64) PReadError!usize {
         if (is_windows) {
             return windows.ReadFile(self.handle, buffer, offset, self.intended_io_mode);
@@ -1004,6 +1006,8 @@ pub const File = struct {
 
     /// Returns the number of bytes read. If the number read is smaller than `buffer.len`, it
     /// means the file reached the end. Reaching the end of a file is not an error condition.
+    /// On Windows, this function currently does alter the file pointer.
+    /// https://github.com/ziglang/zig/issues/12783
     pub fn preadAll(self: File, buffer: []u8, offset: u64) PReadError!usize {
         var index: usize = 0;
         while (index != buffer.len) {
@@ -1058,6 +1062,8 @@ pub const File = struct {
     }
 
     /// See https://github.com/ziglang/zig/issues/7699
+    /// On Windows, this function currently does alter the file pointer.
+    /// https://github.com/ziglang/zig/issues/12783
     pub fn preadv(self: File, iovecs: []const os.iovec, offset: u64) PReadError!usize {
         if (is_windows) {
             // TODO improve this to use ReadFileScatter
@@ -1079,6 +1085,8 @@ pub const File = struct {
     /// The `iovecs` parameter is mutable because this function needs to mutate the fields in
     /// order to handle partial reads from the underlying OS layer.
     /// See https://github.com/ziglang/zig/issues/7699
+    /// On Windows, this function currently does alter the file pointer.
+    /// https://github.com/ziglang/zig/issues/12783
     pub fn preadvAll(self: File, iovecs: []os.iovec, offset: u64) PReadError!usize {
         if (iovecs.len == 0) return 0;
 
@@ -1122,6 +1130,8 @@ pub const File = struct {
         }
     }
 
+    /// On Windows, this function currently does alter the file pointer.
+    /// https://github.com/ziglang/zig/issues/12783
     pub fn pwrite(self: File, bytes: []const u8, offset: u64) PWriteError!usize {
         if (is_windows) {
             return windows.WriteFile(self.handle, bytes, offset, self.intended_io_mode);
@@ -1134,6 +1144,8 @@ pub const File = struct {
         }
     }
 
+    /// On Windows, this function currently does alter the file pointer.
+    /// https://github.com/ziglang/zig/issues/12783
     pub fn pwriteAll(self: File, bytes: []const u8, offset: u64) PWriteError!void {
         var index: usize = 0;
         while (index < bytes.len) {
@@ -1179,6 +1191,8 @@ pub const File = struct {
     }
 
     /// See https://github.com/ziglang/zig/issues/7699
+    /// On Windows, this function currently does alter the file pointer.
+    /// https://github.com/ziglang/zig/issues/12783
     pub fn pwritev(self: File, iovecs: []os.iovec_const, offset: u64) PWriteError!usize {
         if (is_windows) {
             // TODO improve this to use WriteFileScatter
@@ -1197,6 +1211,8 @@ pub const File = struct {
     /// The `iovecs` parameter is mutable because this function needs to mutate the fields in
     /// order to handle partial writes from the underlying OS layer.
     /// See https://github.com/ziglang/zig/issues/7699
+    /// On Windows, this function currently does alter the file pointer.
+    /// https://github.com/ziglang/zig/issues/12783
     pub fn pwritevAll(self: File, iovecs: []os.iovec_const, offset: u64) PWriteError!void {
         if (iovecs.len == 0) return;
 

@@ -3055,14 +3055,26 @@ fn writeVecSectionHeader(file: fs.File, offset: u64, section: wasm.Section, size
     buf[0] = @enumToInt(section);
     leb.writeUnsignedFixed(5, buf[1..6], size);
     leb.writeUnsignedFixed(5, buf[6..], items);
-    try file.pwriteAll(&buf, offset);
+
+    if (builtin.target.os.tag == .windows) {
+        // https://github.com/ziglang/zig/issues/12783
+        const curr_pos = try file.getPos();
+        try file.pwriteAll(&buf, offset);
+        try file.seekTo(curr_pos);
+    } else try file.pwriteAll(&buf, offset);
 }
 
 fn writeCustomSectionHeader(file: fs.File, offset: u64, size: u32) !void {
     var buf: [1 + 5]u8 = undefined;
     buf[0] = 0; // 0 = 'custom' section
     leb.writeUnsignedFixed(5, buf[1..6], size);
-    try file.pwriteAll(&buf, offset);
+
+    if (builtin.target.os.tag == .windows) {
+        // https://github.com/ziglang/zig/issues/12783
+        const curr_pos = try file.getPos();
+        try file.pwriteAll(&buf, offset);
+        try file.seekTo(curr_pos);
+    } else try file.pwriteAll(&buf, offset);
 }
 
 fn emitLinkSection(self: *Wasm, file: fs.File, arena: Allocator, symbol_table: *std.AutoArrayHashMap(SymbolLoc, u32)) !void {

@@ -28,35 +28,35 @@ pub fn addCases(cases: *tests.StandaloneContext) void {
 }
 
 fn addWasmCases(cases: *tests.StandaloneContext) void {
-    cases.addBuildFile("test/link/wasm/bss/build.zig", .{
+    cases.addBuildFile("test/link/wasm/archive/build.zig", .{
         .build_modes = true,
         .requires_stage2 = true,
     });
 
-    cases.addBuildFile("test/link/wasm/segments/build.zig", .{
+    cases.addBuildFile("test/link/wasm/bss/build.zig", .{
         .build_modes = true,
         .requires_stage2 = true,
     });
 
-    cases.addBuildFile("test/link/wasm/stack_pointer/build.zig", .{
+    cases.addBuildFile("test/link/wasm/extern/build.zig", .{
         .build_modes = true,
         .requires_stage2 = true,
+        .use_emulation = true,
     });
 
-    cases.addBuildFile("test/link/wasm/type/build.zig", .{
+    cases.addBuildFile("test/link/wasm/segments/build.zig", .{
         .build_modes = true,
         .requires_stage2 = true,
     });
 
-    cases.addBuildFile("test/link/wasm/archive/build.zig", .{
+    cases.addBuildFile("test/link/wasm/stack_pointer/build.zig", .{
         .build_modes = true,
         .requires_stage2 = true,
     });
 
-    cases.addBuildFile("test/link/wasm/extern/build.zig", .{
+    cases.addBuildFile("test/link/wasm/type/build.zig", .{
         .build_modes = true,
         .requires_stage2 = true,
-        .use_emulation = true,
     });
 }