diff --git a/lib/std/build.zig b/lib/std/build.zig
index b2da9da332..7e3c75bc78 100644
--- a/lib/std/build.zig
+++ b/lib/std/build.zig
@@ -1384,6 +1384,7 @@ pub const LibExeObjStep = struct {
     }
 
     fn computeOutFileNames(self: *LibExeObjStep) void {
+        // TODO make this call std.zig.binNameAlloc
         switch (self.kind) {
             .Obj => {
                 self.out_filename = self.builder.fmt("{}{}", .{ self.name, self.target.oFileExt() });
diff --git a/lib/std/target.zig b/lib/std/target.zig
index e1a7e1a2bf..99617c6d0e 100644
--- a/lib/std/target.zig
+++ b/lib/std/target.zig
@@ -483,13 +483,6 @@ pub const Target = struct {
                 else => false,
             };
         }
-
-        pub fn oFileExt(abi: Abi) [:0]const u8 {
-            return switch (abi) {
-                .msvc => ".obj",
-                else => ".o",
-            };
-        }
     };
 
     pub const ObjectFormat = enum {
@@ -1142,8 +1135,18 @@ pub const Target = struct {
         return linuxTripleSimple(allocator, self.cpu.arch, self.os.tag, self.abi);
     }
 
+    pub fn oFileExt_cpu_arch_abi(cpu_arch: Cpu.Arch, abi: Abi) [:0]const u8 {
+        if (cpu_arch.isWasm()) {
+            return ".o.wasm";
+        }
+        switch (abi) {
+            .msvc => return ".obj",
+            else => return ".o",
+        }
+    }
+
     pub fn oFileExt(self: Target) [:0]const u8 {
-        return self.abi.oFileExt();
+        return oFileExt_cpu_arch_abi(self.cpu.arch, self.abi);
     }
 
     pub fn exeFileExtSimple(cpu_arch: Cpu.Arch, os_tag: Os.Tag) [:0]const u8 {
diff --git a/lib/std/zig.zig b/lib/std/zig.zig
index 66226e8dd1..42a33383b7 100644
--- a/lib/std/zig.zig
+++ b/lib/std/zig.zig
@@ -79,13 +79,7 @@ pub fn binNameAlloc(allocator: *std.mem.Allocator, options: BinNameOptions) erro
     const target = options.target;
     switch (options.object_format orelse target.getObjectFormat()) {
         .coff, .pe => switch (options.output_mode) {
-            .Exe => {
-                const suffix = switch (target.os.tag) {
-                    .uefi => ".efi",
-                    else => ".exe",
-                };
-                return std.fmt.allocPrint(allocator, "{s}{s}", .{ root_name, suffix });
-            },
+            .Exe => return std.fmt.allocPrint(allocator, "{s}{s}", .{ root_name, target.exeFileExt() }),
             .Lib => {
                 const suffix = switch (options.link_mode orelse .Static) {
                     .Static => ".lib",
@@ -93,7 +87,7 @@ pub fn binNameAlloc(allocator: *std.mem.Allocator, options: BinNameOptions) erro
                 };
                 return std.fmt.allocPrint(allocator, "{s}{s}", .{ root_name, suffix });
             },
-            .Obj => return std.fmt.allocPrint(allocator, "{s}{s}", .{ root_name, target.abi.oFileExt() }),
+            .Obj => return std.fmt.allocPrint(allocator, "{s}{s}", .{ root_name, target.oFileExt() }),
         },
         .elf => switch (options.output_mode) {
             .Exe => return allocator.dupe(u8, root_name),
@@ -113,7 +107,7 @@ pub fn binNameAlloc(allocator: *std.mem.Allocator, options: BinNameOptions) erro
                     },
                 }
             },
-            .Obj => return std.fmt.allocPrint(allocator, "{s}.o", .{root_name}),
+            .Obj => return std.fmt.allocPrint(allocator, "{s}{s}", .{ root_name, target.oFileExt() }),
         },
         .macho => switch (options.output_mode) {
             .Exe => return allocator.dupe(u8, root_name),
@@ -124,9 +118,13 @@ pub fn binNameAlloc(allocator: *std.mem.Allocator, options: BinNameOptions) erro
                 };
                 return std.fmt.allocPrint(allocator, "{s}{s}{s}", .{ target.libPrefix(), root_name, suffix });
             },
-            .Obj => return std.fmt.allocPrint(allocator, "{s}.o", .{root_name}),
+            .Obj => return std.fmt.allocPrint(allocator, "{s}{s}", .{ root_name, target.oFileExt() }),
+        },
+        .wasm => switch (options.output_mode) {
+            .Exe => return std.fmt.allocPrint(allocator, "{s}{s}", .{ root_name, target.exeFileExt() }),
+            .Obj => return std.fmt.allocPrint(allocator, "{s}{s}", .{ root_name, target.oFileExt() }),
+            .Lib => return std.fmt.allocPrint(allocator, "{s}.wasm", .{root_name}),
         },
-        .wasm => return std.fmt.allocPrint(allocator, "{s}.wasm", .{root_name}),
         .c => return std.fmt.allocPrint(allocator, "{s}.c", .{root_name}),
         .hex => return std.fmt.allocPrint(allocator, "{s}.ihex", .{root_name}),
         .raw => return std.fmt.allocPrint(allocator, "{s}.bin", .{root_name}),
diff --git a/lib/std/zig/cross_target.zig b/lib/std/zig/cross_target.zig
index f94598c30c..f1ae3457a5 100644
--- a/lib/std/zig/cross_target.zig
+++ b/lib/std/zig/cross_target.zig
@@ -466,7 +466,7 @@ pub const CrossTarget = struct {
     }
 
     pub fn oFileExt(self: CrossTarget) [:0]const u8 {
-        return self.getAbi().oFileExt();
+        return Target.oFileExt_cpu_arch_abi(self.getCpuArch(), self.getAbi());
     }
 
     pub fn exeFileExt(self: CrossTarget) [:0]const u8 {
diff --git a/src/Compilation.zig b/src/Compilation.zig
index 9cc2c3aa5c..d60b323216 100644
--- a/src/Compilation.zig
+++ b/src/Compilation.zig
@@ -1520,7 +1520,7 @@ fn updateCObject(comp: *Compilation, c_object: *CObject) !void {
         comp.bin_file.options.root_name
     else
         mem.split(c_source_basename, ".").next().?;
-    const o_basename = try std.fmt.allocPrint(arena, "{}{}", .{ o_basename_noext, comp.getTarget().oFileExt() });
+    const o_basename = try std.fmt.allocPrint(arena, "{s}{s}", .{ o_basename_noext, comp.getTarget().oFileExt() });
 
     const digest = if (!comp.disable_c_depfile and try man.hit()) man.final() else blk: {
         var argv = std.ArrayList([]const u8).init(comp.gpa);
diff --git a/src/link.zig b/src/link.zig
index 51bf8a64ae..2d215ea0dc 100644
--- a/src/link.zig
+++ b/src/link.zig
@@ -176,7 +176,7 @@ pub const File = struct {
                 };
             }
             // Open a temporary object file, not the final output file because we want to link with LLD.
-            break :blk try std.fmt.allocPrint(allocator, "{}{}", .{ emit.sub_path, options.target.oFileExt() });
+            break :blk try std.fmt.allocPrint(allocator, "{s}{s}", .{ emit.sub_path, options.target.oFileExt() });
         } else emit.sub_path;
         errdefer if (use_lld) allocator.free(sub_path);