coff: only store PDB basename

Author: ypsvlq

lib/std/coff.zig

@@ -1101,7 +1101,7 @@ pub const Coff = struct {
         return coff;
     }
 
-    pub fn getPdbPath(self: *Coff, buffer: []u8) !?usize {
+    pub fn getPdbPath(self: *Coff) !?[]const u8 {
         assert(self.is_image);
 
         const data_dirs = self.getDataDirectories();
@@ -1145,17 +1145,9 @@ pub const Coff = struct {
         self.age = try reader.readInt(u32, .little);
 
         // Finally read the null-terminated string.
-        var byte = try reader.readByte();
-        i = 0;
-        while (byte != 0 and i < buffer.len) : (i += 1) {
-            buffer[i] = byte;
-            byte = try reader.readByte();
-        }
-
-        if (byte != 0 and i == buffer.len)
-            return error.NameTooLong;
-
-        return @as(usize, i);
+        const start = reader.context.pos;
+        const len = std.mem.indexOfScalar(u8, self.data[start..], 0) orelse return null;
+        return self.data[start .. start + len];
     }
 
     pub fn getCoffHeader(self: Coff) CoffHeader {

lib/std/debug.zig

@@ -1093,12 +1093,17 @@ fn readCoffDebugInfo(allocator: mem.Allocator, coff_obj: *coff.Coff) !ModuleDebu
             di.dwarf = dwarf;
         }
 
-        var path_buf: [windows.MAX_PATH]u8 = undefined;
-        const len = try coff_obj.getPdbPath(path_buf[0..]) orelse return di;
-        const raw_path = path_buf[0..len];
-
-        const path = try fs.path.resolve(allocator, &[_][]const u8{raw_path});
-        defer allocator.free(path);
+        const raw_path = try coff_obj.getPdbPath() orelse return di;
+        const path = blk: {
+            if (fs.path.isAbsolute(raw_path)) {
+                break :blk raw_path;
+            } else {
+                const self_dir = try fs.selfExeDirPathAlloc(allocator);
+                defer allocator.free(self_dir);
+                break :blk try fs.path.join(allocator, &.{ self_dir, raw_path });
+            }
+        };
+        defer if (path.ptr != raw_path.ptr) allocator.free(path);
 
         di.pdb = pdb.Pdb.init(allocator, path) catch |err| switch (err) {
             error.FileNotFound, error.IsDir => {

src/link/Coff/lld.zig

@@ -184,9 +184,10 @@ pub fn linkWithLLD(self: *Coff, arena: Allocator, prog_node: *std.Progress.Node)
             const out_pdb = self.pdb_out_path orelse try allocPrint(arena, "{s}.pdb", .{
                 full_out_path[0 .. full_out_path.len - out_ext.len],
             });
+            const out_pdb_basename = std.fs.path.basename(out_pdb);
 
             try argv.append(try allocPrint(arena, "-PDB:{s}", .{out_pdb}));
-            try argv.append(try allocPrint(arena, "-PDBALTPATH:{s}", .{out_pdb}));
+            try argv.append(try allocPrint(arena, "-PDBALTPATH:{s}", .{out_pdb_basename}));
         }
         if (comp.version) |version| {
             try argv.append(try allocPrint(arena, "-VERSION:{}.{}", .{ version.major, version.minor }));