From b01b972999f024a694734fa9861827e5dc15a88b Mon Sep 17 00:00:00 2001
From: Jakub Konka <kubkon@jakubkonka.com>
Date: Mon, 25 Sep 2023 19:50:12 +0200
Subject: [PATCH] elf: test linking against empty C object

---
 test/link/elf.zig | 58 +++++++++++++++++++++++++++++++----------------
 1 file changed, 38 insertions(+), 20 deletions(-)

diff --git a/test/link/elf.zig b/test/link/elf.zig
index b20498e7df..5c910df1ab 100644
--- a/test/link/elf.zig
+++ b/test/link/elf.zig
@@ -12,35 +12,27 @@ pub fn build(b: *Build) void {
         .abi = .musl,
     };
 
-    elf_step.dependOn(testLinkingZig(b, .{ .use_llvm = true }));
+    // Exercise linker with self-hosted backend (no LLVM)
     elf_step.dependOn(testLinkingZig(b, .{ .use_llvm = false }));
-    elf_step.dependOn(testLinkingC(b, .{ .target = musl_target, .use_llvm = true }));
-    // elf_step.dependOn(testLinkingC(b, .{ .target = musl_target, .use_llvm = false })); // TODO arocc
+
+    // Exercise linker with LLVM backend
+    elf_step.dependOn(testEmptyObject(b, .{ .target = musl_target }));
+    elf_step.dependOn(testLinkingC(b, .{ .target = musl_target }));
+    elf_step.dependOn(testLinkingZig(b, .{}));
 }
 
-fn testLinkingZig(b: *Build, opts: Options) *Step {
-    const test_step = addTestStep(b, "linking-zig-static", opts);
+fn testEmptyObject(b: *Build, opts: Options) *Step {
+    const test_step = addTestStep(b, "empty-object", opts);
 
     const exe = addExecutable(b, opts);
-    addZigSourceBytes(exe,
-        \\pub fn main() void {
-        \\    @import("std").debug.print("Hello World!\n", .{});
-        \\}
-    );
+    addCSourceBytes(exe, "int main() { return 0; }");
+    addCSourceBytes(exe, "");
+    exe.is_linking_libc = true;
 
     const run = b.addRunArtifact(exe);
-    run.expectStdErrEqual("Hello World!\n");
+    run.expectExitCode(0);
     test_step.dependOn(&run.step);
 
-    const check = exe.checkObject();
-    check.checkStart();
-    check.checkExact("header");
-    check.checkExact("type EXEC");
-    check.checkStart();
-    check.checkExact("section headers");
-    check.checkNotPresent("name .dynamic");
-    test_step.dependOn(&check.step);
-
     return test_step;
 }
 
@@ -73,6 +65,32 @@ fn testLinkingC(b: *Build, opts: Options) *Step {
     return test_step;
 }
 
+fn testLinkingZig(b: *Build, opts: Options) *Step {
+    const test_step = addTestStep(b, "linking-zig-static", opts);
+
+    const exe = addExecutable(b, opts);
+    addZigSourceBytes(exe,
+        \\pub fn main() void {
+        \\    @import("std").debug.print("Hello World!\n", .{});
+        \\}
+    );
+
+    const run = b.addRunArtifact(exe);
+    run.expectStdErrEqual("Hello World!\n");
+    test_step.dependOn(&run.step);
+
+    const check = exe.checkObject();
+    check.checkStart();
+    check.checkExact("header");
+    check.checkExact("type EXEC");
+    check.checkStart();
+    check.checkExact("section headers");
+    check.checkNotPresent("name .dynamic");
+    test_step.dependOn(&check.step);
+
+    return test_step;
+}
+
 const Options = struct {
     target: CrossTarget = .{ .cpu_arch = .x86_64, .os_tag = .linux },
     optimize: std.builtin.OptimizeMode = .Debug,