test: add a test for dwarf embedded in coff

test/standalone.zig

@@ -234,6 +234,10 @@ pub const build_cases = [_]BuildCase{
         .build_root = "test/standalone/stack_iterator",
         .import = @import("standalone/stack_iterator/build.zig"),
     },
+    .{
+        .build_root = "test/standalone/coff_dwarf",
+        .import = @import("standalone/coff_dwarf/build.zig"),
+    },
 };
 
 const std = @import("std");

test/standalone/coff_dwarf/build.zig

@@ -0,0 +1,35 @@
+const std = @import("std");
+const builtin = @import("builtin");
+
+/// This tests the path where DWARF information is embedded in a COFF binary
+pub fn build(b: *std.Build) void {
+    const test_step = b.step("test", "Test it");
+    b.default_step = test_step;
+
+    const optimize: std.builtin.OptimizeMode = .Debug;
+    const target = b.standardTargetOptions(.{});
+
+    if (builtin.os.tag != .windows) return;
+
+    const exe = b.addExecutable(.{
+        .name = "main",
+        .root_source_file = .{ .path = "main.zig" },
+        .optimize = optimize,
+        .target = target,
+    });
+
+    const lib = b.addSharedLibrary(.{
+        .name = "shared_lib",
+        .optimize = optimize,
+        .target = target,
+    });
+    lib.addCSourceFile("shared_lib.c", &.{"-gdwarf"});
+    lib.linkLibC();
+    exe.linkLibrary(lib);
+
+    const run = b.addRunArtifact(exe);
+    run.expectExitCode(0);
+    run.skip_foreign_checks = true;
+
+    test_step.dependOn(&run.step);
+}

test/standalone/coff_dwarf/main.zig

@@ -0,0 +1,27 @@
+const std = @import("std");
+const assert = std.debug.assert;
+const testing = std.testing;
+
+extern fn add(a: u32, b: u32, addr: *usize) u32;
+
+pub fn main() !void {
+    var gpa = std.heap.GeneralPurposeAllocator(.{}){};
+    defer assert(gpa.deinit() == .ok);
+    const allocator = gpa.allocator();
+
+    var debug_info = try std.debug.openSelfDebugInfo(allocator);
+    defer debug_info.deinit();
+
+    var add_addr: usize = undefined;
+    _ = add(1, 2, &add_addr);
+
+    const module = try debug_info.getModuleForAddress(add_addr);
+    const symbol = try module.getSymbolAtAddress(allocator, add_addr);
+    defer symbol.deinit(allocator);
+
+    try testing.expectEqualStrings("add", symbol.symbol_name);
+    try testing.expect(symbol.line_info != null);
+    try testing.expectEqualStrings("shared_lib.c", std.fs.path.basename(symbol.line_info.?.file_name));
+    try testing.expectEqual(@as(u64, 3), symbol.line_info.?.line);
+    try testing.expectEqual(@as(u64, 0), symbol.line_info.?.column);
+}

test/standalone/coff_dwarf/shared_lib.c

@@ -0,0 +1,6 @@
+#include <stdint.h>
+
+__declspec(dllexport) uint32_t add(uint32_t a, uint32_t b, uintptr_t* addr) {
+    *addr = (uintptr_t)&add;
+    return a + b;
+}