Adds per_crate_rustc_flag build setting. (#1827)

* Adds per_crate_rustc_flag build setting.

* Regenerate documentation

Author: csmulhern

BUILD.bazel

@@ -1,5 +1,5 @@
 load("@bazel_skylib//:bzl_library.bzl", "bzl_library")
-load("//rust:defs.bzl", "capture_clippy_output", "clippy_flags", "error_format", "extra_exec_rustc_flag", "extra_exec_rustc_flags", "extra_rustc_flag", "extra_rustc_flags", "is_proc_macro_dep", "is_proc_macro_dep_enabled")
+load("//rust:defs.bzl", "capture_clippy_output", "clippy_flags", "error_format", "extra_exec_rustc_flag", "extra_exec_rustc_flags", "extra_rustc_flag", "extra_rustc_flags", "is_proc_macro_dep", "is_proc_macro_dep_enabled", "per_crate_rustc_flag")
 
 exports_files(["LICENSE"])
 
@@ -76,6 +76,12 @@ extra_exec_rustc_flag(
     visibility = ["//visibility:public"],
 )
 
+per_crate_rustc_flag(
+    name = "experimental_per_crate_rustc_flag",
+    build_setting_default = "",
+    visibility = ["//visibility:public"],
+)
+
 # This setting is used by the clippy rules. See https://bazelbuild.github.io/rules_rust/rust_clippy.html
 label_flag(
     name = "clippy.toml",

docs/flatten.md

@@ -1137,8 +1137,8 @@ Run the test with `bazel test //hello_lib:greeting_test`.
 rust_toolchain(<a href="#rust_toolchain-name">name</a>, <a href="#rust_toolchain-allocator_library">allocator_library</a>, <a href="#rust_toolchain-binary_ext">binary_ext</a>, <a href="#rust_toolchain-cargo">cargo</a>, <a href="#rust_toolchain-clippy_driver">clippy_driver</a>, <a href="#rust_toolchain-debug_info">debug_info</a>,
                <a href="#rust_toolchain-default_edition">default_edition</a>, <a href="#rust_toolchain-dylib_ext">dylib_ext</a>, <a href="#rust_toolchain-env">env</a>, <a href="#rust_toolchain-exec_triple">exec_triple</a>, <a href="#rust_toolchain-experimental_use_cc_common_link">experimental_use_cc_common_link</a>,
                <a href="#rust_toolchain-extra_exec_rustc_flags">extra_exec_rustc_flags</a>, <a href="#rust_toolchain-extra_rustc_flags">extra_rustc_flags</a>, <a href="#rust_toolchain-llvm_cov">llvm_cov</a>, <a href="#rust_toolchain-llvm_profdata">llvm_profdata</a>, <a href="#rust_toolchain-llvm_tools">llvm_tools</a>,
-               <a href="#rust_toolchain-opt_level">opt_level</a>, <a href="#rust_toolchain-os">os</a>, <a href="#rust_toolchain-rust_doc">rust_doc</a>, <a href="#rust_toolchain-rust_std">rust_std</a>, <a href="#rust_toolchain-rustc">rustc</a>, <a href="#rust_toolchain-rustc_lib">rustc_lib</a>, <a href="#rust_toolchain-rustfmt">rustfmt</a>, <a href="#rust_toolchain-staticlib_ext">staticlib_ext</a>,
-               <a href="#rust_toolchain-stdlib_linkflags">stdlib_linkflags</a>, <a href="#rust_toolchain-target_json">target_json</a>, <a href="#rust_toolchain-target_triple">target_triple</a>)
+               <a href="#rust_toolchain-opt_level">opt_level</a>, <a href="#rust_toolchain-os">os</a>, <a href="#rust_toolchain-per_crate_rustc_flags">per_crate_rustc_flags</a>, <a href="#rust_toolchain-rust_doc">rust_doc</a>, <a href="#rust_toolchain-rust_std">rust_std</a>, <a href="#rust_toolchain-rustc">rustc</a>, <a href="#rust_toolchain-rustc_lib">rustc_lib</a>, <a href="#rust_toolchain-rustfmt">rustfmt</a>,
+               <a href="#rust_toolchain-staticlib_ext">staticlib_ext</a>, <a href="#rust_toolchain-stdlib_linkflags">stdlib_linkflags</a>, <a href="#rust_toolchain-target_json">target_json</a>, <a href="#rust_toolchain-target_triple">target_triple</a>)
 </pre>
 
 Declares a Rust toolchain for use.
@@ -1205,6 +1205,7 @@ See @rules_rust//rust:repositories.bzl for examples of defining the @rust_cpuX r
 | <a id="rust_toolchain-llvm_tools"></a>llvm_tools |  LLVM tools that are shipped with the Rust toolchain.   | <a href="https://bazel.build/concepts/labels">Label</a> | optional | <code>None</code> |
 | <a id="rust_toolchain-opt_level"></a>opt_level |  Rustc optimization levels.   | <a href="https://bazel.build/rules/lib/dict">Dictionary: String -> String</a> | optional | <code>{"dbg": "0", "fastbuild": "0", "opt": "3"}</code> |
 | <a id="rust_toolchain-os"></a>os |  The operating system for the current toolchain   | String | optional | <code>""</code> |
+| <a id="rust_toolchain-per_crate_rustc_flags"></a>per_crate_rustc_flags |  Extra flags to pass to rustc in non-exec configuration   | List of strings | optional | <code>[]</code> |
 | <a id="rust_toolchain-rust_doc"></a>rust_doc |  The location of the <code>rustdoc</code> binary. Can be a direct source or a filegroup containing one item.   | <a href="https://bazel.build/concepts/labels">Label</a> | required |  |
 | <a id="rust_toolchain-rust_std"></a>rust_std |  The Rust standard library.   | <a href="https://bazel.build/concepts/labels">Label</a> | optional | <code>None</code> |
 | <a id="rust_toolchain-rustc"></a>rustc |  The location of the <code>rustc</code> binary. Can be a direct source or a filegroup containing one item.   | <a href="https://bazel.build/concepts/labels">Label</a> | required |  |

docs/rust_repositories.md

@@ -39,8 +39,8 @@ A dedicated filegroup-like rule for Rust stdlib artifacts.
 rust_toolchain(<a href="#rust_toolchain-name">name</a>, <a href="#rust_toolchain-allocator_library">allocator_library</a>, <a href="#rust_toolchain-binary_ext">binary_ext</a>, <a href="#rust_toolchain-cargo">cargo</a>, <a href="#rust_toolchain-clippy_driver">clippy_driver</a>, <a href="#rust_toolchain-debug_info">debug_info</a>,
                <a href="#rust_toolchain-default_edition">default_edition</a>, <a href="#rust_toolchain-dylib_ext">dylib_ext</a>, <a href="#rust_toolchain-env">env</a>, <a href="#rust_toolchain-exec_triple">exec_triple</a>, <a href="#rust_toolchain-experimental_use_cc_common_link">experimental_use_cc_common_link</a>,
                <a href="#rust_toolchain-extra_exec_rustc_flags">extra_exec_rustc_flags</a>, <a href="#rust_toolchain-extra_rustc_flags">extra_rustc_flags</a>, <a href="#rust_toolchain-llvm_cov">llvm_cov</a>, <a href="#rust_toolchain-llvm_profdata">llvm_profdata</a>, <a href="#rust_toolchain-llvm_tools">llvm_tools</a>,
-               <a href="#rust_toolchain-opt_level">opt_level</a>, <a href="#rust_toolchain-os">os</a>, <a href="#rust_toolchain-rust_doc">rust_doc</a>, <a href="#rust_toolchain-rust_std">rust_std</a>, <a href="#rust_toolchain-rustc">rustc</a>, <a href="#rust_toolchain-rustc_lib">rustc_lib</a>, <a href="#rust_toolchain-rustfmt">rustfmt</a>, <a href="#rust_toolchain-staticlib_ext">staticlib_ext</a>,
-               <a href="#rust_toolchain-stdlib_linkflags">stdlib_linkflags</a>, <a href="#rust_toolchain-target_json">target_json</a>, <a href="#rust_toolchain-target_triple">target_triple</a>)
+               <a href="#rust_toolchain-opt_level">opt_level</a>, <a href="#rust_toolchain-os">os</a>, <a href="#rust_toolchain-per_crate_rustc_flags">per_crate_rustc_flags</a>, <a href="#rust_toolchain-rust_doc">rust_doc</a>, <a href="#rust_toolchain-rust_std">rust_std</a>, <a href="#rust_toolchain-rustc">rustc</a>, <a href="#rust_toolchain-rustc_lib">rustc_lib</a>, <a href="#rust_toolchain-rustfmt">rustfmt</a>,
+               <a href="#rust_toolchain-staticlib_ext">staticlib_ext</a>, <a href="#rust_toolchain-stdlib_linkflags">stdlib_linkflags</a>, <a href="#rust_toolchain-target_json">target_json</a>, <a href="#rust_toolchain-target_triple">target_triple</a>)
 </pre>
 
 Declares a Rust toolchain for use.
@@ -107,6 +107,7 @@ See @rules_rust//rust:repositories.bzl for examples of defining the @rust_cpuX r
 | <a id="rust_toolchain-llvm_tools"></a>llvm_tools |  LLVM tools that are shipped with the Rust toolchain.   | <a href="https://bazel.build/concepts/labels">Label</a> | optional | <code>None</code> |
 | <a id="rust_toolchain-opt_level"></a>opt_level |  Rustc optimization levels.   | <a href="https://bazel.build/rules/lib/dict">Dictionary: String -> String</a> | optional | <code>{"dbg": "0", "fastbuild": "0", "opt": "3"}</code> |
 | <a id="rust_toolchain-os"></a>os |  The operating system for the current toolchain   | String | optional | <code>""</code> |
+| <a id="rust_toolchain-per_crate_rustc_flags"></a>per_crate_rustc_flags |  Extra flags to pass to rustc in non-exec configuration   | List of strings | optional | <code>[]</code> |
 | <a id="rust_toolchain-rust_doc"></a>rust_doc |  The location of the <code>rustdoc</code> binary. Can be a direct source or a filegroup containing one item.   | <a href="https://bazel.build/concepts/labels">Label</a> | required |  |
 | <a id="rust_toolchain-rust_std"></a>rust_std |  The Rust standard library.   | <a href="https://bazel.build/concepts/labels">Label</a> | optional | <code>None</code> |
 | <a id="rust_toolchain-rustc"></a>rustc |  The location of the <code>rustc</code> binary. Can be a direct source or a filegroup containing one item.   | <a href="https://bazel.build/concepts/labels">Label</a> | required |  |

rust/defs.bzl

@@ -49,6 +49,7 @@ load(
     _extra_rustc_flags = "extra_rustc_flags",
     _is_proc_macro_dep = "is_proc_macro_dep",
     _is_proc_macro_dep_enabled = "is_proc_macro_dep_enabled",
+    _per_crate_rustc_flag = "per_crate_rustc_flag",
 )
 load(
     "//rust/private:rustdoc.bzl",
@@ -124,6 +125,9 @@ is_proc_macro_dep = _is_proc_macro_dep
 is_proc_macro_dep_enabled = _is_proc_macro_dep_enabled
 # See @rules_rust//rust/private:rustc.bzl for a complete description.
 
+per_crate_rustc_flag = _per_crate_rustc_flag
+# See @rules_rust//rust/private:rustc.bzl for a complete description.
+
 rust_common = _rust_common
 # See @rules_rust//rust/private:common.bzl for a complete description.
 

rust/private/clippy.bzl

@@ -220,8 +220,8 @@ rust_clippy_aspect = aspect(
         "_extra_rustc_flag": attr.label(
             default = Label("//:extra_rustc_flag"),
         ),
-        "_extra_rustc_flags": attr.label(
-            default = Label("//:extra_rustc_flags"),
+        "_per_crate_rustc_flag": attr.label(
+            default = Label("//:experimental_per_crate_rustc_flag"),
         ),
         "_process_wrapper": attr.label(
             doc = "A process wrapper for running clippy on all platforms",

rust/private/rust.bzl

@@ -682,6 +682,9 @@ _common_attrs = {
     "_is_proc_macro_dep_enabled": attr.label(
         default = Label("//:is_proc_macro_dep_enabled"),
     ),
+    "_per_crate_rustc_flag": attr.label(
+        default = Label("//:experimental_per_crate_rustc_flag"),
+    ),
     "_process_wrapper": attr.label(
         doc = "A process wrapper for running rustc on all platforms.",
         default = Label("//util/process_wrapper"),

rust/private/rustc.bzl

@@ -63,6 +63,11 @@ ExtraExecRustcFlagsInfo = provider(
     fields = {"extra_exec_rustc_flags": "List[string] Extra flags to pass to rustc in exec configuration"},
 )
 
+PerCrateRustcFlagsInfo = provider(
+    doc = "Pass each value as an additional flag to non-exec rustc invocations for crates matching the provided filter",
+    fields = {"per_crate_rustc_flags": "List[string] Extra flags to pass to rustc in non-exec configuration"},
+)
+
 IsProcMacroDepInfo = provider(
     doc = "Records if this is a transitive dependency of a proc-macro.",
     fields = {"is_proc_macro_dep": "Boolean"},
@@ -1003,6 +1008,10 @@ def construct_arguments(
     if hasattr(ctx.attr, "_extra_rustc_flag") and not is_exec_configuration(ctx):
         rustc_flags.add_all(ctx.attr._extra_rustc_flag[ExtraRustcFlagsInfo].extra_rustc_flags)
 
+    if hasattr(ctx.attr, "_per_crate_rustc_flag") and not is_exec_configuration(ctx):
+        per_crate_rustc_flags = ctx.attr._per_crate_rustc_flag[PerCrateRustcFlagsInfo].per_crate_rustc_flags
+        _add_per_crate_rustc_flags(ctx, rustc_flags, crate_info, per_crate_rustc_flags)
+
     if hasattr(ctx.attr, "_extra_exec_rustc_flags") and is_exec_configuration(ctx):
         rustc_flags.add_all(ctx.attr._extra_exec_rustc_flags[ExtraExecRustcFlagsInfo].extra_exec_rustc_flags)
 
@@ -1845,6 +1854,32 @@ def _get_dirname(file):
     """
     return file.dirname
 
+def _add_per_crate_rustc_flags(ctx, args, crate_info, per_crate_rustc_flags):
+    """Adds matching per-crate rustc flags to an arguments object reference
+
+    Args:
+        ctx (ctx): The source rule's context object
+        args (Args): A reference to an Args object
+        crate_info (CrateInfo): A CrateInfo provider
+        per_crate_rustc_flags (list): A list of per_crate_rustc_flag values
+    """
+    for per_crate_rustc_flag in per_crate_rustc_flags:
+        at_index = per_crate_rustc_flag.find("@")
+        if at_index == -1:
+            fail("per_crate_rustc_flag '{}' does not follow the expected format: prefix_filter@flag".format(per_crate_rustc_flag))
+
+        prefix_filter = per_crate_rustc_flag[:at_index]
+        flag = per_crate_rustc_flag[at_index + 1:]
+        if not flag:
+            fail("per_crate_rustc_flag '{}' does not follow the expected format: prefix_filter@flag".format(per_crate_rustc_flag))
+
+        label_string = str(ctx.label)
+        label = label_string[1:] if label_string.startswith("@//") else label_string
+        execution_path = crate_info.root.path
+
+        if label.startswith(prefix_filter) or execution_path.startswith(prefix_filter):
+            args.add(flag)
+
 def _error_format_impl(ctx):
     """Implementation of the `error_format` rule
 
@@ -1923,3 +1958,19 @@ extra_exec_rustc_flag = rule(
     implementation = _extra_exec_rustc_flag_impl,
     build_setting = config.string(flag = True, allow_multiple = True),
 )
+
+def _per_crate_rustc_flag_impl(ctx):
+    return PerCrateRustcFlagsInfo(per_crate_rustc_flags = [f for f in ctx.build_setting_value if f != ""])
+
+per_crate_rustc_flag = rule(
+    doc = (
+        "Add additional rustc_flag to matching crates from the command line with `--@rules_rust//:experimental_per_crate_rustc_flag`. " +
+        "The expected flag format is prefix_filter@flag, where any crate with a label or execution path starting with the prefix filter will be built with the given flag." +
+        "The label matching uses the canonical form of the label (i.e //package:label_name)." +
+        "The execution path is the relative path to your workspace directory including the base name (including extension) of the crate root." +
+        "This flag is only applied to the exec configuration (proc-macros, cargo_build_script, etc)." +
+        "Multiple uses are accumulated."
+    ),
+    implementation = _per_crate_rustc_flag_impl,
+    build_setting = config.string(flag = True, allow_multiple = True),
+)

rust/toolchain.bzl

@@ -578,6 +578,7 @@ def _rust_toolchain_impl(ctx):
         stdlib_linkflags = stdlib_linkflags_cc_info,
         extra_rustc_flags = ctx.attr.extra_rustc_flags,
         extra_exec_rustc_flags = ctx.attr.extra_exec_rustc_flags,
+        per_crate_rustc_flags = ctx.attr.per_crate_rustc_flags,
         sysroot = sysroot_path,
         sysroot_short_path = sysroot_short_path,
         target_arch = target_arch,
@@ -680,6 +681,9 @@ rust_toolchain = rule(
         "os": attr.string(
             doc = "The operating system for the current toolchain",
         ),
+        "per_crate_rustc_flags": attr.string_list(
+            doc = "Extra flags to pass to rustc in non-exec configuration",
+        ),
         "rust_doc": attr.label(
             doc = "The location of the `rustdoc` binary. Can be a direct source or a filegroup containing one item.",
             allow_single_file = True,

test/unit/per_crate_rustc_flag/BUILD.bazel

@@ -0,0 +1,5 @@
+load(":per_crate_rustc_flag_test.bzl", "per_crate_rustc_flag_test_suite")
+
+per_crate_rustc_flag_test_suite(
+    name = "per_crate_rustc_flag_test_suite",
+)

test/unit/per_crate_rustc_flag/lib.rs

@@ -0,0 +1 @@
+pub fn call() {}