test: test for issues starting codegen on many targets

Specifically this is to make sure llvm data layout generation doesn't
regress.  The no emit bin is to allow testing targets that can't
currently be linked.  The commented out targets are ones that fail in
the linker anyway when no emit bin is passed.

lib/std/Build/Step.zig

@@ -294,7 +294,7 @@ pub fn evalZigProcess(
     s: *Step,
     argv: []const []const u8,
     prog_node: *std.Progress.Node,
-) ![]const u8 {
+) !?[]const u8 {
     assert(argv.len != 0);
     const b = s.owner;
     const arena = b.allocator;
@@ -423,6 +423,8 @@ pub fn evalZigProcess(
         });
     }
 
+    if (s.cast(Compile)) |compile| if (compile.emit_bin == .no_emit) return result;
+
     return result orelse return s.fail(
         "the following command failed to communicate the compilation result:\n{s}",
         .{try allocPrintCmd(arena, null, argv)},

lib/std/Build/Step/Compile.zig

@@ -1997,7 +1997,7 @@ fn make(step: *Step, prog_node: *std.Progress.Node) !void {
         try zig_args.append(resolved_args_file);
     }
 
-    const output_bin_path = step.evalZigProcess(zig_args.items, prog_node) catch |err| switch (err) {
+    const maybe_output_bin_path = step.evalZigProcess(zig_args.items, prog_node) catch |err| switch (err) {
         error.NeedCompileErrorCheck => {
             assert(self.expect_errors.len != 0);
             try checkCompileErrors(self);
@@ -2005,10 +2005,11 @@ fn make(step: *Step, prog_node: *std.Progress.Node) !void {
         },
         else => |e| return e,
     };
-    const output_dir = fs.path.dirname(output_bin_path).?;
 
     // Update generated files
-    {
+    if (maybe_output_bin_path) |output_bin_path| {
+        const output_dir = fs.path.dirname(output_bin_path).?;
+
         self.output_dirname_source.path = output_dir;
 
         self.output_path_source.path = b.pathJoin(

lib/std/Build/Step/TranslateC.zig

@@ -148,8 +148,8 @@ fn make(step: *Step, prog_node: *std.Progress.Node) !void {
 
     const output_path = try step.evalZigProcess(argv_list.items, prog_node);
 
-    self.out_basename = fs.path.basename(output_path);
+    self.out_basename = fs.path.basename(output_path.?);
-    const output_dir = fs.path.dirname(output_path).?;
+    const output_dir = fs.path.dirname(output_path.?).?;
 
     self.output_file.path = try fs.path.join(
         b.allocator,

src/Compilation.zig

@@ -1053,6 +1053,7 @@ pub fn create(gpa: Allocator, options: InitOptions) !*Compilation {
                     buf.appendSliceAssumeCapacity(",");
                 }
             }
+            if (buf.items.len == 0) break :blk "";
             assert(mem.endsWith(u8, buf.items, ","));
             buf.items[buf.items.len - 1] = 0;
             buf.shrinkAndFree(buf.items.len);

test/cases.zig

@@ -4,5 +4,6 @@ const Cases = @import("src/Cases.zig");
 pub fn addCases(cases: *Cases) !void {
     try @import("compile_errors.zig").addCases(cases);
     try @import("cbe.zig").addCases(cases);
+    try @import("llvm_targets.zig").addCases(cases);
     try @import("nvptx.zig").addCases(cases);
 }

test/llvm_targets.zig

@@ -0,0 +1,117 @@
+const std = @import("std");
+const Cases = @import("src/Cases.zig");
+
+const targets = [_]std.zig.CrossTarget{
+    .{ .cpu_arch = .aarch64, .os_tag = .freestanding, .abi = .none },
+    .{ .cpu_arch = .aarch64, .os_tag = .linux, .abi = .none },
+    .{ .cpu_arch = .aarch64, .os_tag = .macos, .abi = .none },
+    .{ .cpu_arch = .aarch64, .os_tag = .uefi, .abi = .none },
+    .{ .cpu_arch = .aarch64, .os_tag = .windows, .abi = .gnu },
+    .{ .cpu_arch = .aarch64, .os_tag = .windows, .abi = .msvc },
+    .{ .cpu_arch = .aarch64_be, .os_tag = .freestanding, .abi = .none },
+    .{ .cpu_arch = .aarch64_be, .os_tag = .linux, .abi = .none },
+    .{ .cpu_arch = .aarch64_32, .os_tag = .freestanding, .abi = .none },
+    .{ .cpu_arch = .aarch64_32, .os_tag = .linux, .abi = .none },
+    .{ .cpu_arch = .amdgcn, .os_tag = .amdhsa, .abi = .none },
+    .{ .cpu_arch = .amdgcn, .os_tag = .amdpal, .abi = .none },
+    .{ .cpu_arch = .amdgcn, .os_tag = .linux, .abi = .none },
+    //.{ .cpu_arch = .amdgcn, .os_tag = .mesa3d, .abi = .none },
+    .{ .cpu_arch = .arm, .os_tag = .freestanding, .abi = .none },
+    .{ .cpu_arch = .arm, .os_tag = .linux, .abi = .none },
+    .{ .cpu_arch = .arm, .os_tag = .uefi, .abi = .none },
+    .{ .cpu_arch = .armeb, .os_tag = .freestanding, .abi = .none },
+    .{ .cpu_arch = .armeb, .os_tag = .linux, .abi = .none },
+    .{ .cpu_arch = .avr, .os_tag = .freebsd, .abi = .none },
+    .{ .cpu_arch = .avr, .os_tag = .freestanding, .abi = .none },
+    .{ .cpu_arch = .avr, .os_tag = .linux, .abi = .none },
+    .{ .cpu_arch = .bpfel, .os_tag = .linux, .abi = .gnu },
+    .{ .cpu_arch = .bpfel, .os_tag = .linux, .abi = .none },
+    .{ .cpu_arch = .bpfeb, .os_tag = .linux, .abi = .gnu },
+    .{ .cpu_arch = .bpfeb, .os_tag = .linux, .abi = .none },
+    .{ .cpu_arch = .hexagon, .os_tag = .linux, .abi = .none },
+    .{ .cpu_arch = .mips, .os_tag = .linux, .abi = .gnueabihf },
+    .{ .cpu_arch = .mips, .os_tag = .linux, .abi = .musl },
+    .{ .cpu_arch = .mips, .os_tag = .linux, .abi = .none },
+    .{ .cpu_arch = .mipsel, .os_tag = .linux, .abi = .gnueabihf },
+    .{ .cpu_arch = .mipsel, .os_tag = .linux, .abi = .musl },
+    .{ .cpu_arch = .mipsel, .os_tag = .linux, .abi = .none },
+    .{ .cpu_arch = .mips64, .os_tag = .linux, .abi = .none },
+    .{ .cpu_arch = .mips64el, .os_tag = .linux, .abi = .none },
+    .{ .cpu_arch = .msp430, .os_tag = .freebsd, .abi = .none },
+    .{ .cpu_arch = .msp430, .os_tag = .freestanding, .abi = .none },
+    .{ .cpu_arch = .msp430, .os_tag = .linux, .abi = .none },
+    //.{ .cpu_arch = .nvptx, .os_tag = .cuda, .abi = .none },
+    //.{ .cpu_arch = .nvptx64, .os_tag = .cuda, .abi = .none },
+    .{ .cpu_arch = .powerpc, .os_tag = .freebsd, .abi = .none },
+    .{ .cpu_arch = .powerpc, .os_tag = .freestanding, .abi = .none },
+    .{ .cpu_arch = .powerpc, .os_tag = .linux, .abi = .gnueabihf },
+    .{ .cpu_arch = .powerpc, .os_tag = .linux, .abi = .musl },
+    .{ .cpu_arch = .powerpc, .os_tag = .linux, .abi = .none },
+    .{ .cpu_arch = .powerpcle, .os_tag = .freebsd, .abi = .none },
+    .{ .cpu_arch = .powerpcle, .os_tag = .freestanding, .abi = .none },
+    .{ .cpu_arch = .powerpcle, .os_tag = .linux, .abi = .gnu },
+    .{ .cpu_arch = .powerpcle, .os_tag = .linux, .abi = .musl },
+    .{ .cpu_arch = .powerpcle, .os_tag = .linux, .abi = .none },
+    .{ .cpu_arch = .powerpc64, .os_tag = .freebsd, .abi = .none },
+    .{ .cpu_arch = .powerpc64, .os_tag = .freestanding, .abi = .none },
+    .{ .cpu_arch = .powerpc64, .os_tag = .linux, .abi = .gnu },
+    .{ .cpu_arch = .powerpc64, .os_tag = .linux, .abi = .musl },
+    .{ .cpu_arch = .powerpc64, .os_tag = .linux, .abi = .none },
+    .{ .cpu_arch = .powerpc64le, .os_tag = .freebsd, .abi = .none },
+    .{ .cpu_arch = .powerpc64le, .os_tag = .freestanding, .abi = .none },
+    .{ .cpu_arch = .powerpc64le, .os_tag = .linux, .abi = .gnu },
+    .{ .cpu_arch = .powerpc64le, .os_tag = .linux, .abi = .musl },
+    .{ .cpu_arch = .powerpc64le, .os_tag = .linux, .abi = .none },
+    //.{ .cpu_arch = .r600, .os_tag = .mesa3d, .abi = .none },
+    .{ .cpu_arch = .riscv32, .os_tag = .freestanding, .abi = .none },
+    .{ .cpu_arch = .riscv32, .os_tag = .linux, .abi = .none },
+    .{ .cpu_arch = .riscv64, .os_tag = .freestanding, .abi = .none },
+    .{ .cpu_arch = .riscv64, .os_tag = .linux, .abi = .gnu },
+    .{ .cpu_arch = .riscv64, .os_tag = .linux, .abi = .musl },
+    .{ .cpu_arch = .riscv64, .os_tag = .linux, .abi = .none },
+    .{ .cpu_arch = .s390x, .os_tag = .freestanding, .abi = .none },
+    .{ .cpu_arch = .s390x, .os_tag = .linux, .abi = .gnu },
+    .{ .cpu_arch = .sparc, .os_tag = .freestanding, .abi = .none },
+    .{ .cpu_arch = .sparc, .os_tag = .linux, .abi = .gnu },
+    .{ .cpu_arch = .sparc, .os_tag = .linux, .abi = .none },
+    .{ .cpu_arch = .sparcel, .os_tag = .freestanding, .abi = .none },
+    .{ .cpu_arch = .sparcel, .os_tag = .linux, .abi = .gnu },
+    .{ .cpu_arch = .sparc64, .os_tag = .freestanding, .abi = .none },
+    .{ .cpu_arch = .sparc64, .os_tag = .linux, .abi = .gnu },
+    //.{ .cpu_arch = .spirv32, .os_tag = .opencl, .abi = .none },
+    //.{ .cpu_arch = .spirv32, .os_tag = .glsl450, .abi = .none },
+    //.{ .cpu_arch = .spirv32, .os_tag = .vulkan, .abi = .none },
+    //.{ .cpu_arch = .spirv64, .os_tag = .opencl, .abi = .none },
+    //.{ .cpu_arch = .spirv64, .os_tag = .glsl450, .abi = .none },
+    //.{ .cpu_arch = .spirv64, .os_tag = .vulkan, .abi = .none },
+    .{ .cpu_arch = .thumb, .os_tag = .freestanding, .abi = .none },
+    .{ .cpu_arch = .thumbeb, .os_tag = .freestanding, .abi = .none },
+    .{ .cpu_arch = .ve, .os_tag = .linux, .abi = .none },
+    .{ .cpu_arch = .wasm32, .os_tag = .emscripten, .abi = .none },
+    .{ .cpu_arch = .wasm32, .os_tag = .freestanding, .abi = .none },
+    .{ .cpu_arch = .wasm32, .os_tag = .linux, .abi = .none },
+    .{ .cpu_arch = .wasm32, .os_tag = .wasi, .abi = .none },
+    .{ .cpu_arch = .wasm64, .os_tag = .emscripten, .abi = .none },
+    .{ .cpu_arch = .wasm64, .os_tag = .freestanding, .abi = .none },
+    .{ .cpu_arch = .wasm64, .os_tag = .linux, .abi = .none },
+    .{ .cpu_arch = .wasm64, .os_tag = .wasi, .abi = .none },
+    .{ .cpu_arch = .x86, .os_tag = .freestanding, .abi = .none },
+    .{ .cpu_arch = .x86, .os_tag = .linux, .abi = .none },
+    .{ .cpu_arch = .x86, .os_tag = .uefi, .abi = .none },
+    .{ .cpu_arch = .x86, .os_tag = .windows, .abi = .gnu },
+    .{ .cpu_arch = .x86, .os_tag = .windows, .abi = .msvc },
+    .{ .cpu_arch = .x86_64, .os_tag = .freebsd, .abi = .none },
+    .{ .cpu_arch = .x86_64, .os_tag = .freestanding, .abi = .none },
+    .{ .cpu_arch = .x86_64, .os_tag = .linux, .abi = .none },
+    .{ .cpu_arch = .x86_64, .os_tag = .macos, .abi = .none },
+    .{ .cpu_arch = .x86_64, .os_tag = .uefi, .abi = .none },
+    .{ .cpu_arch = .x86_64, .os_tag = .windows, .abi = .gnu },
+    .{ .cpu_arch = .x86_64, .os_tag = .windows, .abi = .msvc },
+};
+
+pub fn addCases(ctx: *Cases) !void {
+    for (targets) |target| {
+        var case = ctx.noEmitUsingLlvmBackend("llvm_targets", target);
+        case.addCompile("");
+    }
+}

test/src/Cases.zig

@@ -76,6 +76,7 @@ pub const Case = struct {
     output_mode: std.builtin.OutputMode,
     optimize_mode: std.builtin.Mode = .Debug,
     updates: std.ArrayList(Update),
+    emit_bin: bool = true,
     emit_h: bool = false,
     is_test: bool = false,
     expect_exact: bool = false,
@@ -176,6 +177,19 @@ pub fn exeFromCompiledC(ctx: *Cases, name: []const u8, target: CrossTarget) *Cas
     return &ctx.cases.items[ctx.cases.items.len - 1];
 }
 
+pub fn noEmitUsingLlvmBackend(ctx: *Cases, name: []const u8, target: CrossTarget) *Case {
+    ctx.cases.append(Case{
+        .name = name,
+        .target = target,
+        .updates = std.ArrayList(Update).init(ctx.cases.allocator),
+        .output_mode = .Obj,
+        .emit_bin = false,
+        .deps = std.ArrayList(DepModule).init(ctx.arena),
+        .backend = .llvm,
+    }) catch @panic("out of memory");
+    return &ctx.cases.items[ctx.cases.items.len - 1];
+}
+
 /// Adds a test case that uses the LLVM backend to emit an executable.
 /// Currently this implies linking libc, because only then we can generate a testable executable.
 pub fn exeUsingLlvmBackend(ctx: *Cases, name: []const u8, target: CrossTarget) *Case {
@@ -537,6 +551,8 @@ pub fn lowerToBuildSteps(
             }),
         };
 
+        artifact.emit_bin = if (case.emit_bin) .default else .no_emit;
+
         if (case.link_libc) artifact.linkLibC();
 
         switch (case.backend) {