Support -Cpanic=abort

.bazelci/presubmit.yml

@@ -496,6 +496,15 @@ tasks:
       - "//..."
     build_flags:
       - "--@rules_rust//rust/settings:experimental_use_cc_common_link=True"
+  ubuntu2004_panic_abort:
+    name: -Cabort=panic
+    platform: ubuntu2004
+    build_targets: *default_linux_targets
+    test_targets: *default_linux_targets
+    build_flags:
+      - "--@rules_rust//:panic_style=abort"
+    test_flags:
+      - "--@rules_rust//:panic_style=abort"
   android_examples_ubuntu2004:
     name: Android Examples
     platform: ubuntu2004

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", "per_crate_rustc_flag")
+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", "panic_style", "per_crate_rustc_flag")
 
 exports_files(["LICENSE"])
 
@@ -18,6 +18,13 @@ error_format(
     visibility = ["//visibility:public"],
 )
 
+# This setting may be changed from the command line to panic immediately upon abort.
+panic_style(
+    name = "panic_style",
+    build_setting_default = "",
+    visibility = ["//visibility:public"],
+)
+
 # This setting may be used to pass extra options to clippy from the command line.
 # It applies across all targets.
 clippy_flags(

docs/BUILD.bazel

@@ -55,6 +55,7 @@ PAGES = dict([
             "rust_test",
             "rust_test_suite",
             "error_format",
+            "panic_style",
             "extra_rustc_flag",
             "extra_rustc_flags",
             "capture_clippy_output",

docs/defs.md

@@ -9,6 +9,7 @@
 * [rust_test](#rust_test)
 * [rust_test_suite](#rust_test_suite)
 * [error_format](#error_format)
+* [panic_style](#panic_style)
 * [extra_rustc_flag](#extra_rustc_flag)
 * [extra_rustc_flags](#extra_rustc_flags)
 * [capture_clippy_output](#capture_clippy_output)
@@ -85,6 +86,24 @@ Add additional rustc_flags from the command line with `--@rules_rust//:extra_rus
 | <a id="extra_rustc_flags-name"></a>name |  A unique name for this target.   | <a href="https://bazel.build/concepts/labels#target-names">Name</a> | required |  |
 
 
+<a id="panic_style"></a>
+
+## panic_style
+
+<pre>
+panic_style(<a href="#panic_style-name">name</a>)
+</pre>
+
+Change the [-Cpanic](https://doc.rust-lang.org/rustc/codegen-options/index.html#panic) flag from the command line with `--@rules_rust//:panic_style`. See rustc documentation for valid values. Automatically set to `unwind` for proc macros and tests, or the per-target default.
+
+**ATTRIBUTES**
+
+
+| Name  | Description | Type | Mandatory | Default |
+| :------------- | :------------- | :------------- | :------------- | :------------- |
+| <a id="panic_style-name"></a>name |  A unique name for this target.   | <a href="https://bazel.build/concepts/labels#target-names">Name</a> | required |  |
+
+
 <a id="rust_binary"></a>
 
 ## rust_binary

docs/flatten.md

@@ -13,6 +13,7 @@
 * [extra_rustc_flags](#extra_rustc_flags)
 * [fail_when_enabled](#fail_when_enabled)
 * [incompatible_flag](#incompatible_flag)
+* [panic_style](#panic_style)
 * [rules_rust_dependencies](#rules_rust_dependencies)
 * [rust_analyzer_aspect](#rust_analyzer_aspect)
 * [rust_analyzer_toolchain](#rust_analyzer_toolchain)
@@ -199,6 +200,24 @@ A rule defining an incompatible flag.
 | <a id="incompatible_flag-issue"></a>issue |  The link to the github issue associated with this flag   | String | required |  |
 
 
+<a id="panic_style"></a>
+
+## panic_style
+
+<pre>
+panic_style(<a href="#panic_style-name">name</a>)
+</pre>
+
+Change the [-Cpanic](https://doc.rust-lang.org/rustc/codegen-options/index.html#panic) flag from the command line with `--@rules_rust//:panic_style`. See rustc documentation for valid values. Automatically set to `unwind` for proc macros and tests, or the per-target default.
+
+**ATTRIBUTES**
+
+
+| Name  | Description | Type | Mandatory | Default |
+| :------------- | :------------- | :------------- | :------------- | :------------- |
+| <a id="panic_style-name"></a>name |  A unique name for this target.   | <a href="https://bazel.build/concepts/labels#target-names">Name</a> | required |  |
+
+
 <a id="rust_analyzer_toolchain"></a>
 
 ## rust_analyzer_toolchain

docs/symbols.bzl

@@ -51,6 +51,7 @@ load(
     _error_format = "error_format",
     _extra_rustc_flag = "extra_rustc_flag",
     _extra_rustc_flags = "extra_rustc_flags",
+    _panic_style = "panic_style",
     _rust_analyzer_aspect = "rust_analyzer_aspect",
     _rust_binary = "rust_binary",
     _rust_clippy = "rust_clippy",
@@ -175,6 +176,7 @@ rustfmt_test = _rustfmt_test
 rustfmt_toolchain = _rustfmt_toolchain
 
 error_format = _error_format
+panic_style = _panic_style
 extra_rustc_flag = _extra_rustc_flag
 extra_rustc_flags = _extra_rustc_flags
 incompatible_flag = _incompatible_flag

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",
+    _panic_style = "panic_style",
     _per_crate_rustc_flag = "per_crate_rustc_flag",
 )
 load(
@@ -107,6 +108,9 @@ capture_clippy_output = _capture_clippy_output
 error_format = _error_format
 # See @rules_rust//rust/private:rustc.bzl for a complete description.
 
+panic_style = _panic_style
+# See @rules_rust//rust/private:rustc.bzl for a complete description.
+
 extra_rustc_flag = _extra_rustc_flag
 # See @rules_rust//rust/private:rustc.bzl for a complete description.
 

rust/private/rust.bzl

@@ -26,6 +26,7 @@ load(
     "determine_output_hash",
     "expand_dict_value_locations",
     "find_toolchain",
+    "force_panic_unwind_transition",
     "get_import_macro_deps",
     "transform_deps",
 )
@@ -682,6 +683,9 @@ _common_attrs = {
     "_is_proc_macro_dep_enabled": attr.label(
         default = Label("//:is_proc_macro_dep_enabled"),
     ),
+    "_panic_style": attr.label(
+        default = Label("//:panic_style"),
+    ),
     "_per_crate_rustc_flag": attr.label(
         default = Label("//:experimental_per_crate_rustc_flag"),
     ),
@@ -910,6 +914,7 @@ _proc_macro_dep_transition = transition(
 rust_proc_macro = rule(
     implementation = _rust_proc_macro_impl,
     provides = _common_providers,
+    cfg = force_panic_unwind_transition,
     # Start by copying the common attributes, then override the `deps` attribute
     # to apply `_proc_macro_dep_transition`. To add this transition we additionally
     # need to declare `_allowlist_function_transition`, see
@@ -1132,7 +1137,11 @@ rust_test = rule(
     implementation = _rust_test_impl,
     provides = _common_providers,
     attrs = dict(_common_attrs.items() +
-                 _rust_test_attrs.items()),
+                 _rust_test_attrs.items() + {
+        "_allowlist_function_transition": attr.label(
+            default = "@bazel_tools//tools/allowlists/function_transition_allowlist",
+        ),
+    }.items()),
     executable = True,
     fragments = ["cpp"],
     host_fragments = ["cpp"],
@@ -1141,6 +1150,7 @@ rust_test = rule(
         str(Label("//rust:toolchain_type")),
         "@bazel_tools//tools/cpp:toolchain_type",
     ],
+    cfg = force_panic_unwind_transition,
     incompatible_use_toolchain_transition = True,
     doc = dedent("""\
         Builds a Rust test crate.

rust/private/rustc.bzl

@@ -53,6 +53,13 @@ ErrorFormatInfo = provider(
     fields = {"error_format": "(string) [" + ", ".join(_error_format_values) + "]"},
 )
 
+_panic_style_values = ["unwind", "abort", ""]
+
+PanicStyleInfo = provider(
+    doc = "Set the panic style",
+    fields = {"panic_style": "(string) [" + ", ".join(_panic_style_values) + "]"},
+)
+
 ExtraRustcFlagsInfo = provider(
     doc = "Pass each value as an additional flag to non-exec rustc invocations",
     fields = {"extra_rustc_flags": "List[string] Extra flags to pass to rustc in non-exec configuration"},
@@ -611,7 +618,7 @@ def collect_inputs(
         force_depend_on_objects (bool, optional): Forces dependencies of this rule to be objects rather than
             metadata, even for libraries. This is used in rustdoc tests.
         experimental_use_cc_common_link (bool, optional): Whether rules_rust uses cc_common.link to link
-	    rust binaries.
+            rust binaries.
 
     Returns:
         tuple: A tuple: A tuple of the following items:
@@ -884,6 +891,8 @@ def construct_arguments(
 
     rustc_flags.add("--error-format=" + error_format)
 
+    rustc_flags.add("-Cpanic=" + _get_panic_style(ctx, toolchain))
+
     # Mangle symbols to disambiguate crates with the same name. This could
     # happen only for non-final artifacts where we compute an output_hash,
     # e.g., rust_library.
@@ -1029,6 +1038,30 @@ def construct_arguments(
 
     return args, env
 
+def _get_panic_style(ctx, toolchain):
+    panic_style = "unwind"
+
+    # Most targets default to unwind, but a few default to abort. Can't find a list in the
+    # documentation, this list is extracted from `library/panic_unwind/src/lib.rs` as of 1.68.1.
+    target_triple = toolchain.target_triple
+    if target_triple.arch.startswith("wasm") or target_triple.arch == "avr" or target_triple.system in ("none", "uefi", "espidf"):
+        panic_style = "abort"
+
+    if hasattr(ctx.attr, "_panic_style"):
+        flag_value = ctx.attr._panic_style[PanicStyleInfo].panic_style
+        if flag_value:
+            panic_style = flag_value
+    return panic_style
+
+def _get_libstd_and_allocator_ccinfo(ctx, toolchain):
+    panic_style = _get_panic_style(ctx, toolchain)
+    if panic_style == "unwind":
+        return toolchain.unwind_libstd_and_allocator_ccinfo
+    elif panic_style == "abort":
+        return toolchain.abort_libstd_and_allocator_ccinfo
+    else:
+        fail("Unrecognized panic style: " + panic_style)
+
 def rustc_compile_action(
         ctx,
         attr,
@@ -1267,7 +1300,7 @@ def rustc_compile_action(
         )
 
         # Collect the linking contexts of the standard library and dependencies.
-        linking_contexts = [toolchain.libstd_and_allocator_ccinfo.linking_context, toolchain.stdlib_linkflags.linking_context]
+        linking_contexts = [_get_libstd_and_allocator_ccinfo(ctx, toolchain).linking_context, toolchain.stdlib_linkflags.linking_context]
 
         for dep in crate_info.deps.to_list():
             if dep.cc_info:
@@ -1486,9 +1519,10 @@ def establish_cc_info(ctx, attr, crate_info, toolchain, cc_toolchain, feature_co
             else:
                 cc_infos.append(dep.cc_info)
 
-    if crate_info.type in ("rlib", "lib") and toolchain.libstd_and_allocator_ccinfo:
+    libstd_and_allocator_ccinfo = _get_libstd_and_allocator_ccinfo(ctx, toolchain)
+    if crate_info.type in ("rlib", "lib") and libstd_and_allocator_ccinfo:
         # TODO: if we already have an rlib in our deps, we could skip this
-        cc_infos.append(toolchain.libstd_and_allocator_ccinfo)
+        cc_infos.append(libstd_and_allocator_ccinfo)
 
     return [cc_common.merge_cc_infos(cc_infos = cc_infos)]
 
@@ -1907,6 +1941,34 @@ error_format = rule(
     build_setting = config.string(flag = True),
 )
 
+def _panic_style_impl(ctx):
+    """Implementation of the `panic_style` rule
+
+    Args:
+        ctx (ctx): The rule's context object
+
+    Returns:
+        list: A list containing the PanicStyleInfo provider
+    """
+    raw = ctx.build_setting_value
+    if raw not in _panic_style_values:
+        fail("{} expected a value in `{}` but got `{}`".format(
+            ctx.label,
+            _panic_style_values,
+            raw,
+        ))
+    return [PanicStyleInfo(panic_style = raw)]
+
+panic_style = rule(
+    doc = (
+        "Change the [-Cpanic](https://doc.rust-lang.org/rustc/codegen-options/index.html#panic) " +
+        "flag from the command line with `--@rules_rust//:panic_style`. See rustc documentation for valid values. " +
+        "Automatically set to `unwind` for proc macros and tests, or the per-target default."
+    ),
+    implementation = _panic_style_impl,
+    build_setting = config.string(flag = True),
+)
+
 def _extra_rustc_flags_impl(ctx):
     return ExtraRustcFlagsInfo(extra_rustc_flags = ctx.build_setting_value)
 

rust/private/rustdoc_test.bzl

@@ -17,7 +17,7 @@
 load("//rust/private:common.bzl", "rust_common")
 load("//rust/private:providers.bzl", "CrateInfo")
 load("//rust/private:rustdoc.bzl", "rustdoc_compile_action")
-load("//rust/private:utils.bzl", "dedent", "find_toolchain", "transform_deps")
+load("//rust/private:utils.bzl", "dedent", "find_toolchain", "force_panic_unwind_transition", "transform_deps")
 
 def _construct_writer_arguments(ctx, test_runner, opt_test_params, action, crate_info):
     """Construct arguments and environment variables specific to `rustdoc_test_writer`.
@@ -207,6 +207,9 @@ rust_doc_test = rule(
             """),
             providers = [CrateInfo, CcInfo],
         ),
+        "_allowlist_function_transition": attr.label(
+            default = "@bazel_tools//tools/allowlists/function_transition_allowlist",
+        ),
         "_cc_toolchain": attr.label(
             doc = (
                 "In order to use find_cc_toolchain, your rule has to depend " +
@@ -229,6 +232,7 @@ rust_doc_test = rule(
         ),
     },
     test = True,
+    cfg = force_panic_unwind_transition,
     fragments = ["cpp"],
     host_fragments = ["cpp"],
     toolchains = [

rust/private/utils.bzl

@@ -724,3 +724,12 @@ def _shortest_src_with_basename(srcs, basename):
             if not shortest or len(f.dirname) < len(shortest.dirname):
                 shortest = f
     return shortest
+
+def _force_panic_unwind_transition_impl(_settings, _attr):
+    return {"//:panic_style": "unwind"}
+
+force_panic_unwind_transition = transition(
+    implementation = _force_panic_unwind_transition_impl,
+    inputs = [],
+    outputs = ["//:panic_style"],
+)