feat: support location and make variable expansion

.bazelrc

@@ -15,8 +15,8 @@ import %workspace%/.bazelrc.remote
 # To update these lines, execute
 # `bazel run @rules_bazel_integration_test//tools:update_deleted_packages`
 # docs: https://bazel.build/reference/command-line-reference#flag--deleted_packages
-build --deleted_packages=e2e/workspace,e2e/workspace/c-sources,e2e/workspace/configure-mode,e2e/workspace/configure-target,e2e/workspace/configure-threaded,e2e/workspace/data-dependencies,e2e/workspace/embed-file,e2e/workspace/include-dependencies,e2e/workspace/include-dependencies/zig-include,e2e/workspace/include-dependencies/zig-include-define,e2e/workspace/include-dependencies/zig-include-isystem,e2e/workspace/include-dependencies/zig-std-include,e2e/workspace/link-dependencies,e2e/workspace/link-dependencies/shared-library,e2e/workspace/link-dependencies/static-library,e2e/workspace/linker-script,e2e/workspace/multiple-sources-and-packages-test,e2e/workspace/multiple-sources-binary,e2e/workspace/simple-binary,e2e/workspace/simple-library,e2e/workspace/simple-shared-library,e2e/workspace/simple-test,e2e/workspace/transitive-zig-packages-binary,e2e/workspace/transitive-zig-packages-binary/hello-world,e2e/workspace/transitive-zig-packages-binary/hello-world/data,e2e/workspace/transitive-zig-packages-binary/hello-world/data/hello,e2e/workspace/transitive-zig-packages-binary/hello-world/data/world,e2e/workspace/transitive-zig-packages-binary/hello-world/io,e2e/workspace/zig-package-binary,e2e/workspace/zig-package-binary/data,e2e/workspace/zig-package-binary/io,zig/tests/integration_tests/workspace,zig/tests/integration_tests/workspace/custom_interpreter
-query --deleted_packages=e2e/workspace,e2e/workspace/c-sources,e2e/workspace/configure-mode,e2e/workspace/configure-target,e2e/workspace/configure-threaded,e2e/workspace/data-dependencies,e2e/workspace/embed-file,e2e/workspace/include-dependencies,e2e/workspace/include-dependencies/zig-include,e2e/workspace/include-dependencies/zig-include-define,e2e/workspace/include-dependencies/zig-include-isystem,e2e/workspace/include-dependencies/zig-std-include,e2e/workspace/link-dependencies,e2e/workspace/link-dependencies/shared-library,e2e/workspace/link-dependencies/static-library,e2e/workspace/linker-script,e2e/workspace/multiple-sources-and-packages-test,e2e/workspace/multiple-sources-binary,e2e/workspace/simple-binary,e2e/workspace/simple-library,e2e/workspace/simple-shared-library,e2e/workspace/simple-test,e2e/workspace/transitive-zig-packages-binary,e2e/workspace/transitive-zig-packages-binary/hello-world,e2e/workspace/transitive-zig-packages-binary/hello-world/data,e2e/workspace/transitive-zig-packages-binary/hello-world/data/hello,e2e/workspace/transitive-zig-packages-binary/hello-world/data/world,e2e/workspace/transitive-zig-packages-binary/hello-world/io,e2e/workspace/zig-package-binary,e2e/workspace/zig-package-binary/data,e2e/workspace/zig-package-binary/io,zig/tests/integration_tests/workspace,zig/tests/integration_tests/workspace/custom_interpreter
+build --deleted_packages=e2e/workspace,e2e/workspace/c-sources,e2e/workspace/configure-mode,e2e/workspace/configure-target,e2e/workspace/configure-threaded,e2e/workspace/data-dependencies,e2e/workspace/embed-file,e2e/workspace/include-dependencies,e2e/workspace/include-dependencies/zig-include,e2e/workspace/include-dependencies/zig-include-define,e2e/workspace/include-dependencies/zig-include-isystem,e2e/workspace/include-dependencies/zig-std-include,e2e/workspace/link-dependencies,e2e/workspace/link-dependencies/shared-library,e2e/workspace/link-dependencies/static-library,e2e/workspace/linker-script,e2e/workspace/location-expansion,e2e/workspace/multiple-sources-and-packages-test,e2e/workspace/multiple-sources-binary,e2e/workspace/simple-binary,e2e/workspace/simple-library,e2e/workspace/simple-shared-library,e2e/workspace/simple-test,e2e/workspace/transitive-zig-packages-binary,e2e/workspace/transitive-zig-packages-binary/hello-world,e2e/workspace/transitive-zig-packages-binary/hello-world/data,e2e/workspace/transitive-zig-packages-binary/hello-world/data/hello,e2e/workspace/transitive-zig-packages-binary/hello-world/data/world,e2e/workspace/transitive-zig-packages-binary/hello-world/io,e2e/workspace/zig-package-binary,e2e/workspace/zig-package-binary/data,e2e/workspace/zig-package-binary/io,zig/tests/integration_tests/workspace,zig/tests/integration_tests/workspace/custom_interpreter
+query --deleted_packages=e2e/workspace,e2e/workspace/c-sources,e2e/workspace/configure-mode,e2e/workspace/configure-target,e2e/workspace/configure-threaded,e2e/workspace/data-dependencies,e2e/workspace/embed-file,e2e/workspace/include-dependencies,e2e/workspace/include-dependencies/zig-include,e2e/workspace/include-dependencies/zig-include-define,e2e/workspace/include-dependencies/zig-include-isystem,e2e/workspace/include-dependencies/zig-std-include,e2e/workspace/link-dependencies,e2e/workspace/link-dependencies/shared-library,e2e/workspace/link-dependencies/static-library,e2e/workspace/linker-script,e2e/workspace/location-expansion,e2e/workspace/multiple-sources-and-packages-test,e2e/workspace/multiple-sources-binary,e2e/workspace/simple-binary,e2e/workspace/simple-library,e2e/workspace/simple-shared-library,e2e/workspace/simple-test,e2e/workspace/transitive-zig-packages-binary,e2e/workspace/transitive-zig-packages-binary/hello-world,e2e/workspace/transitive-zig-packages-binary/hello-world/data,e2e/workspace/transitive-zig-packages-binary/hello-world/data/hello,e2e/workspace/transitive-zig-packages-binary/hello-world/data/world,e2e/workspace/transitive-zig-packages-binary/hello-world/io,e2e/workspace/zig-package-binary,e2e/workspace/zig-package-binary/data,e2e/workspace/zig-package-binary/io,zig/tests/integration_tests/workspace,zig/tests/integration_tests/workspace/custom_interpreter
 
 # Load any settings specific to the current user.
 # .bazelrc.user should appear in .gitignore so that settings are not shared with team members

MODULE.bazel

@@ -4,6 +4,7 @@ module(
     compatibility_level = 1,
 )
 
+bazel_dep(name = "aspect_bazel_lib", version = "2.0.0")
 bazel_dep(name = "bazel_skylib", version = "1.5.0")
 bazel_dep(name = "platforms", version = "0.0.8")
 
@@ -15,7 +16,6 @@ register_toolchains("@rules_zig//zig/target:all")
 
 register_toolchains("@zig_toolchains//:all")
 
-bazel_dep(name = "aspect_bazel_lib", version = "2.1.0", dev_dependency = True)
 bazel_dep(name = "stardoc", version = "0.6.2", dev_dependency = True, repo_name = "io_bazel_stardoc")
 bazel_dep(name = "gazelle", version = "0.35.0", dev_dependency = True, repo_name = "bazel_gazelle")
 bazel_dep(name = "bazel_skylib_gazelle_plugin", version = "1.5.0", dev_dependency = True)

e2e/workspace/location-expansion/BUILD.bazel

@@ -0,0 +1,14 @@
+load("@rules_zig//zig:defs.bzl", "zig_test")
+
+zig_test(
+    name = "test",
+    size = "small",
+    copts = [
+        '-DRLOCATIONPATH="$(rlocationpath :data.txt)"',
+        '-DTARGET="$(TARGET)"',
+        '-DZIG_TARGET="$(ZIG_TARGET)"',
+    ],
+    csrcs = ["main.c"],
+    data = ["data.txt"],
+    main = "main.zig",
+)

e2e/workspace/location-expansion/main.c

@@ -0,0 +1,3 @@
+const char *rlocationpath = RLOCATIONPATH;
+const char *target = TARGET;
+const char *zig_target = ZIG_TARGET;

e2e/workspace/location-expansion/main.zig

@@ -0,0 +1,29 @@
+const std = @import("std");
+const builtin = @import("builtin");
+
+extern const rlocationpath: [*:0]const u8;
+extern const target: [*:0]const u8;
+extern const zig_target: [*:0]const u8;
+
+test "RLOCATIONPATH is set" {
+    try std.testing.expectStringEndsWith(
+        std.mem.sliceTo(rlocationpath, 0),
+        "location-expansion/data.txt",
+    );
+}
+
+test "TARGET is set" {
+    try std.testing.expectEqualStrings(
+        "//location-expansion:test",
+        std.mem.sliceTo(target, 0),
+    );
+}
+
+test "ZIG_TARGET is set" {
+    const actual_target = try builtin.target.linuxTriple(std.testing.allocator);
+    defer std.testing.allocator.free(actual_target);
+    try std.testing.expectEqualStrings(
+        actual_target,
+        std.mem.sliceTo(zig_target, 0),
+    );
+}

internal_deps.bzl

@@ -81,13 +81,6 @@ def rules_zig_internal_deps():
         urls = ["https://github.com/bazelbuild/stardoc/releases/download/0.6.2/stardoc-0.6.2.tar.gz"],
     )
 
-    http_archive(
-        name = "aspect_bazel_lib",
-        sha256 = "fc8bd670380eaba5314769abbe9fee21d641e3da06d9d26b8073a301f6d62332",
-        strip_prefix = "bazel-lib-2.1.0",
-        url = "https://github.com/aspect-build/bazel-lib/releases/download/v2.1.0/bazel-lib-v2.1.0.tar.gz",
-    )
-
     http_archive(
         name = "rules_bazel_integration_test",
         sha256 = "6e65d497c68f5794349bfa004369e144063686ce1ebd0227717cd23285be45ef",

zig/private/common/BUILD.bazel

@@ -24,6 +24,7 @@ bzl_library(
         ":data",
         ":filetypes",
         ":linker_script",
+        ":location_expansion",
         ":zig_cache",
         ":zig_lib_dir",
         ":zig_target_triple",
@@ -40,6 +41,13 @@ bzl_library(
     deps = ["@bazel_skylib//lib:paths"],
 )
 
+bzl_library(
+    name = "location_expansion",
+    srcs = ["location_expansion.bzl"],
+    visibility = ["//zig:__subpackages__"],
+    deps = ["@aspect_bazel_lib//lib:expand_make_vars"],
+)
+
 bzl_library(
     name = "csrcs",
     srcs = ["csrcs.bzl"],
@@ -80,6 +88,7 @@ filegroup(
         ":data.bzl",
         ":filetypes.bzl",
         ":linker_script.bzl",
+        ":location_expansion.bzl",
         ":zig_build.bzl",
         ":zig_cache.bzl",
         ":zig_lib_dir.bzl",

zig/private/common/location_expansion.bzl

@@ -0,0 +1,35 @@
+"""Expand location placeholders and make variables on attributes.
+"""
+
+load("@aspect_bazel_lib//lib:expand_make_vars.bzl", "expand_locations", "expand_variables")
+
+def location_expansion(*, ctx, targets, outputs, attribute_name, strings):
+    """Perform location make variable expansion on the given strings.
+
+    Args:
+      ctx: Context object.
+      targets: List of Target, Expand locations of these targets.
+      outputs: List of File, Outputs of the rule to expand.
+      attribute_name: String, The name of the attribute we're expanding.
+      strings: List of String, The actual string values to expand.
+
+    Returns:
+      The given strings with location and make variable references substituted.
+    """
+    result = []
+
+    for s in strings:
+        result.append(
+            expand_variables(
+                ctx,
+                expand_locations(
+                    ctx,
+                    s,
+                    targets,
+                ),
+                outputs,
+                attribute_name,
+            ),
+        )
+
+    return result

zig/private/common/zig_build.bzl

@@ -10,6 +10,7 @@ load(
     "ZIG_SOURCE_EXTENSIONS",
 )
 load("//zig/private/common:linker_script.bzl", "zig_linker_script")
+load("//zig/private/common:location_expansion.bzl", "location_expansion")
 load("//zig/private/common:zig_cache.bzl", "zig_cache_output")
 load("//zig/private/common:zig_lib_dir.bzl", "zig_lib_dir")
 load(
@@ -49,7 +50,7 @@ ATTRS = {
         mandatory = False,
     ),
     "copts": attr.string_list(
-        doc = "C compiler flags required to build the C sources of the target.",
+        doc = "C compiler flags required to build the C sources of the target. Subject to location expansion.",
         mandatory = False,
     ),
     "deps": attr.label_list(
@@ -163,8 +164,18 @@ def zig_build_impl(ctx, *, kind):
     direct_inputs.extend(ctx.files.extra_srcs)
     args.add(ctx.file.main)
 
+    location_targets = ctx.attr.data
+
+    copts = location_expansion(
+        ctx = ctx,
+        targets = location_targets,
+        outputs = outputs,
+        attribute_name = "copts",
+        strings = ctx.attr.copts,
+    )
+
     zig_csrcs(
-        copts = ctx.attr.copts,
+        copts = copts,
         csrcs = ctx.files.csrcs,
         inputs = direct_inputs,
         args = args,

zig/repositories.bzl

@@ -22,7 +22,6 @@ def _http_archive(name, **kwargs):
 def rules_zig_dependencies():
     """Register dependencies required by rules_zig."""
 
-    # The minimal version of bazel_skylib we require
     _http_archive(
         name = "bazel_skylib",
         sha256 = "74d544d96f4a5bb630d465ca8bbcfe231e3594e5aae57e1edbf17a6eb3ca2506",
@@ -32,6 +31,13 @@ def rules_zig_dependencies():
         ],
     )
 
+    _http_archive(
+        name = "aspect_bazel_lib",
+        sha256 = "fc8bd670380eaba5314769abbe9fee21d641e3da06d9d26b8073a301f6d62332",
+        strip_prefix = "bazel-lib-2.1.0",
+        url = "https://github.com/aspect-build/bazel-lib/releases/download/v2.1.0/bazel-lib-v2.1.0.tar.gz",
+    )
+
 ########
 # Remaining content of the file is only used to support toolchains.
 ########