Implement support for dylib linkage (#2414)
This PR implements dylib linkage against the standard library behind a
feature flag
`--@rules_rust//rust/settings:experimental_use_dylib_linkage`.
The main part of this feature is
[here](https://github.com/bazelbuild/rules_rust/pull/2414/files#diff-2a806da393e47c07ffe67c78ace69eb488b4ac44b029a46d8237b8e2a05637beR258)
where we skip exporting static rust stdlibs and export only `libstd.so`
instead.
This feature is useful when the subset of libstd being statically linked
to downstream shared libraries and binaries is **larger** than the
entire dylib version of libstd. The following diagram is the high level
of what dylib linkage is trying to achieve.
Running the feature against `android_binary` yields a size reduction on
the shared library produced by `android_binary` because it doesn't
statically link the rust stdlibs anymore.
```
> bazel build //:android_app --config=android_x86_64
> unzip -l bazel-bin/android_app.apk
Archive: bazel-bin/android_app.apk
Length Date Time Name
--------- ---------- ----- ----
1381968 2010-01-01 00:00 lib/x86_64/libandroid_app.so <--- static link with rust stdlibs
--------- -------
1390294 9 files
```
```
> bazel build //:android_app --config=android_x86_64 --config=dylib_linkage
> unzip -l bazel-bin/android_app.apk
Archive: bazel-bin/android_app.apk
Length Date Time Name
--------- ---------- ----- ----
8080 2010-01-01 00:00 lib/x86_64/libandroid_app.so <--- reduced size because of dynamic linking
13055776 2010-01-01 00:00 lib/x86_64/libstd-8d416d49cf02ecea.so
--------- -------
13072400 10 files
```
Here, the benefit comes when there are enough shared libraries statically linking against the rust stdlibs. "Enough" here means that the total up size of those libraries being more than just the entire `libstd.so`.
TODO: I'm leaving this PR without unit tests until I get some feedback or suggestions on my approach.
---------
Co-authored-by: scentini <rosica@google.com>diff --git a/WORKSPACE.bazel b/WORKSPACE.bazel
index d32161a..8845e38 100644
--- a/WORKSPACE.bazel
+++ b/WORKSPACE.bazel
@@ -79,7 +79,7 @@
http_archive(
name = "rules_testing",
- sha256 = "b84ed8546f1969d700ead4546de9f7637e0f058d835e47e865dcbb13c4210aed",
- strip_prefix = "rules_testing-0.5.0",
- url = "https://github.com/bazelbuild/rules_testing/releases/download/v0.5.0/rules_testing-v0.5.0.tar.gz",
+ sha256 = "02c62574631876a4e3b02a1820cb51167bb9cdcdea2381b2fa9d9b8b11c407c4",
+ strip_prefix = "rules_testing-0.6.0",
+ url = "https://github.com/bazelbuild/rules_testing/releases/download/v0.6.0/rules_testing-v0.6.0.tar.gz",
)
diff --git a/docs/flatten.md b/docs/flatten.md
index 58ec9cb..14d2af6 100644
--- a/docs/flatten.md
+++ b/docs/flatten.md
@@ -1176,10 +1176,11 @@
<pre>
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-global_allocator_library">global_allocator_library</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-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>)
+ <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_link_std_dylib">experimental_link_std_dylib</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-global_allocator_library">global_allocator_library</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-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.
@@ -1241,6 +1242,7 @@
| <a id="rust_toolchain-dylib_ext"></a>dylib_ext | The extension for dynamic libraries created from rustc. | String | required | |
| <a id="rust_toolchain-env"></a>env | Environment variables to set in actions. | <a href="https://bazel.build/rules/lib/dict">Dictionary: String -> String</a> | optional | <code>{}</code> |
| <a id="rust_toolchain-exec_triple"></a>exec_triple | The platform triple for the toolchains execution environment. For more details see: https://docs.bazel.build/versions/master/skylark/rules.html#configurations | String | required | |
+| <a id="rust_toolchain-experimental_link_std_dylib"></a>experimental_link_std_dylib | Label to a boolean build setting that controls whether whether to link libstd dynamically. | <a href="https://bazel.build/concepts/labels">Label</a> | optional | <code>@rules_rust//rust/settings:experimental_link_std_dylib</code> |
| <a id="rust_toolchain-experimental_use_cc_common_link"></a>experimental_use_cc_common_link | Label to a boolean build setting that controls whether cc_common.link is used to link rust binaries. | <a href="https://bazel.build/concepts/labels">Label</a> | optional | <code>//rust/settings:experimental_use_cc_common_link</code> |
| <a id="rust_toolchain-extra_exec_rustc_flags"></a>extra_exec_rustc_flags | Extra flags to pass to rustc in exec configuration | List of strings | optional | <code>[]</code> |
| <a id="rust_toolchain-extra_rustc_flags"></a>extra_rustc_flags | Extra flags to pass to rustc in non-exec configuration | List of strings | optional | <code>[]</code> |
@@ -1446,7 +1448,7 @@
<pre>
CrateInfo(<a href="#CrateInfo-aliases">aliases</a>, <a href="#CrateInfo-compile_data">compile_data</a>, <a href="#CrateInfo-compile_data_targets">compile_data_targets</a>, <a href="#CrateInfo-data">data</a>, <a href="#CrateInfo-deps">deps</a>, <a href="#CrateInfo-edition">edition</a>, <a href="#CrateInfo-is_test">is_test</a>, <a href="#CrateInfo-metadata">metadata</a>, <a href="#CrateInfo-name">name</a>,
<a href="#CrateInfo-output">output</a>, <a href="#CrateInfo-owner">owner</a>, <a href="#CrateInfo-proc_macro_deps">proc_macro_deps</a>, <a href="#CrateInfo-root">root</a>, <a href="#CrateInfo-rustc_env">rustc_env</a>, <a href="#CrateInfo-rustc_env_files">rustc_env_files</a>, <a href="#CrateInfo-rustc_output">rustc_output</a>,
- <a href="#CrateInfo-rustc_rmeta_output">rustc_rmeta_output</a>, <a href="#CrateInfo-srcs">srcs</a>, <a href="#CrateInfo-type">type</a>, <a href="#CrateInfo-wrapped_crate_type">wrapped_crate_type</a>)
+ <a href="#CrateInfo-rustc_rmeta_output">rustc_rmeta_output</a>, <a href="#CrateInfo-srcs">srcs</a>, <a href="#CrateInfo-std_dylib">std_dylib</a>, <a href="#CrateInfo-type">type</a>, <a href="#CrateInfo-wrapped_crate_type">wrapped_crate_type</a>)
</pre>
A provider containing general Crate information.
@@ -1474,6 +1476,7 @@
| <a id="CrateInfo-rustc_output"></a>rustc_output | File: The output from rustc from producing the output file. It is optional. |
| <a id="CrateInfo-rustc_rmeta_output"></a>rustc_rmeta_output | File: The rmeta file produced for this crate. It is optional. |
| <a id="CrateInfo-srcs"></a>srcs | depset[File]: All source Files that are part of the crate. |
+| <a id="CrateInfo-std_dylib"></a>std_dylib | File: libstd.so file |
| <a id="CrateInfo-type"></a>type | str: The type of this crate (see [rustc --crate-type](https://doc.rust-lang.org/rustc/command-line-arguments.html#--crate-type-a-list-of-types-of-crates-for-the-compiler-to-emit)). |
| <a id="CrateInfo-wrapped_crate_type"></a>wrapped_crate_type | str, optional: The original crate type for targets generated using a previously defined crate (typically tests using the <code>rust_test::crate</code> attribute) |
@@ -1533,8 +1536,8 @@
<pre>
StdLibInfo(<a href="#StdLibInfo-alloc_files">alloc_files</a>, <a href="#StdLibInfo-between_alloc_and_core_files">between_alloc_and_core_files</a>, <a href="#StdLibInfo-between_core_and_std_files">between_core_and_std_files</a>, <a href="#StdLibInfo-core_files">core_files</a>,
- <a href="#StdLibInfo-dot_a_files">dot_a_files</a>, <a href="#StdLibInfo-memchr_files">memchr_files</a>, <a href="#StdLibInfo-panic_files">panic_files</a>, <a href="#StdLibInfo-self_contained_files">self_contained_files</a>, <a href="#StdLibInfo-srcs">srcs</a>, <a href="#StdLibInfo-std_files">std_files</a>, <a href="#StdLibInfo-std_rlibs">std_rlibs</a>,
- <a href="#StdLibInfo-test_files">test_files</a>)
+ <a href="#StdLibInfo-dot_a_files">dot_a_files</a>, <a href="#StdLibInfo-memchr_files">memchr_files</a>, <a href="#StdLibInfo-panic_files">panic_files</a>, <a href="#StdLibInfo-self_contained_files">self_contained_files</a>, <a href="#StdLibInfo-srcs">srcs</a>, <a href="#StdLibInfo-std_dylib">std_dylib</a>, <a href="#StdLibInfo-std_files">std_files</a>,
+ <a href="#StdLibInfo-std_rlibs">std_rlibs</a>, <a href="#StdLibInfo-test_files">test_files</a>)
</pre>
A collection of files either found within the `rust-stdlib` artifact or generated based on existing files.
@@ -1553,6 +1556,7 @@
| <a id="StdLibInfo-panic_files"></a>panic_files | Depset[File]: <code>.a</code> files associated with <code>panic_unwind</code> and <code>panic_abort</code>. |
| <a id="StdLibInfo-self_contained_files"></a>self_contained_files | List[File]: All <code>.o</code> files from the <code>self-contained</code> directory. |
| <a id="StdLibInfo-srcs"></a>srcs | List[Target]: All targets from the original <code>srcs</code> attribute. |
+| <a id="StdLibInfo-std_dylib"></a>std_dylib | File: libstd.so file |
| <a id="StdLibInfo-std_files"></a>std_files | Depset[File]: <code>.a</code> files associated with the <code>std</code> module. |
| <a id="StdLibInfo-std_rlibs"></a>std_rlibs | List[File]: All <code>.rlib</code> files |
| <a id="StdLibInfo-test_files"></a>test_files | Depset[File]: <code>.a</code> files associated with the <code>test</code> module. |
diff --git a/docs/providers.md b/docs/providers.md
index 87a3792..bed0a6f 100644
--- a/docs/providers.md
+++ b/docs/providers.md
@@ -12,7 +12,7 @@
<pre>
CrateInfo(<a href="#CrateInfo-aliases">aliases</a>, <a href="#CrateInfo-compile_data">compile_data</a>, <a href="#CrateInfo-compile_data_targets">compile_data_targets</a>, <a href="#CrateInfo-data">data</a>, <a href="#CrateInfo-deps">deps</a>, <a href="#CrateInfo-edition">edition</a>, <a href="#CrateInfo-is_test">is_test</a>, <a href="#CrateInfo-metadata">metadata</a>, <a href="#CrateInfo-name">name</a>,
<a href="#CrateInfo-output">output</a>, <a href="#CrateInfo-owner">owner</a>, <a href="#CrateInfo-proc_macro_deps">proc_macro_deps</a>, <a href="#CrateInfo-root">root</a>, <a href="#CrateInfo-rustc_env">rustc_env</a>, <a href="#CrateInfo-rustc_env_files">rustc_env_files</a>, <a href="#CrateInfo-rustc_output">rustc_output</a>,
- <a href="#CrateInfo-rustc_rmeta_output">rustc_rmeta_output</a>, <a href="#CrateInfo-srcs">srcs</a>, <a href="#CrateInfo-type">type</a>, <a href="#CrateInfo-wrapped_crate_type">wrapped_crate_type</a>)
+ <a href="#CrateInfo-rustc_rmeta_output">rustc_rmeta_output</a>, <a href="#CrateInfo-srcs">srcs</a>, <a href="#CrateInfo-std_dylib">std_dylib</a>, <a href="#CrateInfo-type">type</a>, <a href="#CrateInfo-wrapped_crate_type">wrapped_crate_type</a>)
</pre>
A provider containing general Crate information.
@@ -40,6 +40,7 @@
| <a id="CrateInfo-rustc_output"></a>rustc_output | File: The output from rustc from producing the output file. It is optional. |
| <a id="CrateInfo-rustc_rmeta_output"></a>rustc_rmeta_output | File: The rmeta file produced for this crate. It is optional. |
| <a id="CrateInfo-srcs"></a>srcs | depset[File]: All source Files that are part of the crate. |
+| <a id="CrateInfo-std_dylib"></a>std_dylib | File: libstd.so file |
| <a id="CrateInfo-type"></a>type | str: The type of this crate (see [rustc --crate-type](https://doc.rust-lang.org/rustc/command-line-arguments.html#--crate-type-a-list-of-types-of-crates-for-the-compiler-to-emit)). |
| <a id="CrateInfo-wrapped_crate_type"></a>wrapped_crate_type | str, optional: The original crate type for targets generated using a previously defined crate (typically tests using the <code>rust_test::crate</code> attribute) |
@@ -79,8 +80,8 @@
<pre>
StdLibInfo(<a href="#StdLibInfo-alloc_files">alloc_files</a>, <a href="#StdLibInfo-between_alloc_and_core_files">between_alloc_and_core_files</a>, <a href="#StdLibInfo-between_core_and_std_files">between_core_and_std_files</a>, <a href="#StdLibInfo-core_files">core_files</a>,
- <a href="#StdLibInfo-dot_a_files">dot_a_files</a>, <a href="#StdLibInfo-memchr_files">memchr_files</a>, <a href="#StdLibInfo-panic_files">panic_files</a>, <a href="#StdLibInfo-self_contained_files">self_contained_files</a>, <a href="#StdLibInfo-srcs">srcs</a>, <a href="#StdLibInfo-std_files">std_files</a>, <a href="#StdLibInfo-std_rlibs">std_rlibs</a>,
- <a href="#StdLibInfo-test_files">test_files</a>)
+ <a href="#StdLibInfo-dot_a_files">dot_a_files</a>, <a href="#StdLibInfo-memchr_files">memchr_files</a>, <a href="#StdLibInfo-panic_files">panic_files</a>, <a href="#StdLibInfo-self_contained_files">self_contained_files</a>, <a href="#StdLibInfo-srcs">srcs</a>, <a href="#StdLibInfo-std_dylib">std_dylib</a>, <a href="#StdLibInfo-std_files">std_files</a>,
+ <a href="#StdLibInfo-std_rlibs">std_rlibs</a>, <a href="#StdLibInfo-test_files">test_files</a>)
</pre>
A collection of files either found within the `rust-stdlib` artifact or generated based on existing files.
@@ -99,6 +100,7 @@
| <a id="StdLibInfo-panic_files"></a>panic_files | Depset[File]: <code>.a</code> files associated with <code>panic_unwind</code> and <code>panic_abort</code>. |
| <a id="StdLibInfo-self_contained_files"></a>self_contained_files | List[File]: All <code>.o</code> files from the <code>self-contained</code> directory. |
| <a id="StdLibInfo-srcs"></a>srcs | List[Target]: All targets from the original <code>srcs</code> attribute. |
+| <a id="StdLibInfo-std_dylib"></a>std_dylib | File: libstd.so file |
| <a id="StdLibInfo-std_files"></a>std_files | Depset[File]: <code>.a</code> files associated with the <code>std</code> module. |
| <a id="StdLibInfo-std_rlibs"></a>std_rlibs | List[File]: All <code>.rlib</code> files |
| <a id="StdLibInfo-test_files"></a>test_files | Depset[File]: <code>.a</code> files associated with the <code>test</code> module. |
diff --git a/docs/rust_repositories.md b/docs/rust_repositories.md
index 944f4e4..20d2981 100644
--- a/docs/rust_repositories.md
+++ b/docs/rust_repositories.md
@@ -37,10 +37,11 @@
<pre>
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-global_allocator_library">global_allocator_library</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-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>)
+ <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_link_std_dylib">experimental_link_std_dylib</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-global_allocator_library">global_allocator_library</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-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.
@@ -102,6 +103,7 @@
| <a id="rust_toolchain-dylib_ext"></a>dylib_ext | The extension for dynamic libraries created from rustc. | String | required | |
| <a id="rust_toolchain-env"></a>env | Environment variables to set in actions. | <a href="https://bazel.build/rules/lib/dict">Dictionary: String -> String</a> | optional | <code>{}</code> |
| <a id="rust_toolchain-exec_triple"></a>exec_triple | The platform triple for the toolchains execution environment. For more details see: https://docs.bazel.build/versions/master/skylark/rules.html#configurations | String | required | |
+| <a id="rust_toolchain-experimental_link_std_dylib"></a>experimental_link_std_dylib | Label to a boolean build setting that controls whether whether to link libstd dynamically. | <a href="https://bazel.build/concepts/labels">Label</a> | optional | <code>@rules_rust//rust/settings:experimental_link_std_dylib</code> |
| <a id="rust_toolchain-experimental_use_cc_common_link"></a>experimental_use_cc_common_link | Label to a boolean build setting that controls whether cc_common.link is used to link rust binaries. | <a href="https://bazel.build/concepts/labels">Label</a> | optional | <code>//rust/settings:experimental_use_cc_common_link</code> |
| <a id="rust_toolchain-extra_exec_rustc_flags"></a>extra_exec_rustc_flags | Extra flags to pass to rustc in exec configuration | List of strings | optional | <code>[]</code> |
| <a id="rust_toolchain-extra_rustc_flags"></a>extra_rustc_flags | Extra flags to pass to rustc in non-exec configuration | List of strings | optional | <code>[]</code> |
diff --git a/rust/private/providers.bzl b/rust/private/providers.bzl
index 2bb81ef..c2770dc 100644
--- a/rust/private/providers.bzl
+++ b/rust/private/providers.bzl
@@ -35,6 +35,7 @@
"rustc_output": "File: The output from rustc from producing the output file. It is optional.",
"rustc_rmeta_output": "File: The rmeta file produced for this crate. It is optional.",
"srcs": "depset[File]: All source Files that are part of the crate.",
+ "std_dylib": "File: libstd.so file",
"type": (
"str: The type of this crate " +
"(see [rustc --crate-type](https://doc.rust-lang.org/rustc/command-line-arguments.html#--crate-type-a-list-of-types-of-crates-for-the-compiler-to-emit))."
@@ -122,6 +123,7 @@
"panic_files": "Depset[File]: `.a` files associated with `panic_unwind` and `panic_abort`.",
"self_contained_files": "List[File]: All `.o` files from the `self-contained` directory.",
"srcs": "List[Target]: All targets from the original `srcs` attribute.",
+ "std_dylib": "File: libstd.so file",
"std_files": "Depset[File]: `.a` files associated with the `std` module.",
"std_rlibs": "List[File]: All `.rlib` files",
"test_files": "Depset[File]: `.a` files associated with the `test` module.",
diff --git a/rust/private/rustc.bzl b/rust/private/rustc.bzl
index 4abfdba..e101223 100644
--- a/rust/private/rustc.bzl
+++ b/rust/private/rustc.bzl
@@ -38,6 +38,7 @@
"make_static_lib_symlink",
"relativize",
)
+load(":utils.bzl", "is_std_dylib")
BuildInfo = _BuildInfo
@@ -1035,6 +1036,9 @@
# https://doc.rust-lang.org/rustc/instrument-coverage.html
rustc_flags.add("--codegen=instrument-coverage")
+ if toolchain._experimental_link_std_dylib:
+ rustc_flags.add("--codegen=prefer-dynamic")
+
# Make bin crate data deps available to tests.
for data in getattr(attr, "data", []):
if rust_common.crate_info in data:
@@ -1724,6 +1728,16 @@
for lib in linker_input.libraries
if _is_dylib(lib)
]
+
+ # Include std dylib if dylib linkage is enabled
+ if toolchain._experimental_link_std_dylib:
+ # TODO: Make toolchain.rust_std to only include libstd.so
+ # When dylib linkage is enabled, toolchain.rust_std should only need to
+ # include libstd.so. Hence, no filtering needed.
+ for file in toolchain.rust_std.to_list():
+ if is_std_dylib(file):
+ dylibs.append(file)
+
if not dylibs:
return depset([])
diff --git a/rust/private/utils.bzl b/rust/private/utils.bzl
index 783aa22..06a3d33 100644
--- a/rust/private/utils.bzl
+++ b/rust/private/utils.bzl
@@ -879,3 +879,15 @@
sibling.basename + ".rustc-output",
sibling = sibling,
)
+
+def is_std_dylib(file):
+ """Whether the file is a dylib crate for std
+
+ """
+ basename = file.basename
+ return (
+ # for linux and darwin
+ basename.startswith("libstd-") and (basename.endswith(".so") or basename.endswith(".dylib")) or
+ # for windows
+ basename.startswith("std-") and basename.endswith(".dll")
+ )
diff --git a/rust/settings/BUILD.bazel b/rust/settings/BUILD.bazel
index faaa148..1160e97 100644
--- a/rust/settings/BUILD.bazel
+++ b/rust/settings/BUILD.bazel
@@ -99,6 +99,12 @@
issue = "https://github.com/bazelbuild/rules_rust/issues/2324",
)
+# A flag to control whether to link libstd dynamically.
+bool_flag(
+ name = "experimental_link_std_dylib",
+ build_setting_default = False,
+)
+
# A flag to remove the SYSROOT environment variable from `Rustc` actions.
incompatible_flag(
name = "incompatible_no_rustc_sysroot_env",
diff --git a/rust/toolchain.bzl b/rust/toolchain.bzl
index 9580d7c..1d268ec 100644
--- a/rust/toolchain.bzl
+++ b/rust/toolchain.bzl
@@ -14,6 +14,8 @@
"dedent",
"dedup_expand_location",
"find_cc_toolchain",
+ "is_exec_configuration",
+ "is_std_dylib",
"make_static_lib_symlink",
)
load("//rust/settings:incompatible.bzl", "IncompatibleFlagInfo")
@@ -75,6 +77,13 @@
print("File partitioned: {}".format(f.basename))
fail("rust_toolchain couldn't properly partition rlibs in rust_std. Partitioned {} out of {} files. This is probably a bug in the rule implementation.".format(partitioned_files_len, len(dot_a_files)))
+ std_dylib = None
+
+ for file in rust_std:
+ if is_std_dylib(file):
+ std_dylib = file
+ break
+
return [
DefaultInfo(
files = depset(ctx.files.srcs),
@@ -87,6 +96,7 @@
core_files = core_files,
between_core_and_std_files = between_core_and_std_files,
std_files = std_files,
+ std_dylib = std_dylib,
test_files = test_files,
memchr_files = memchr_files,
alloc_files = alloc_files,
@@ -237,14 +247,27 @@
transitive = [memchr_inputs],
order = "topological",
)
- std_inputs = depset(
- [
- _ltl(f, ctx, cc_toolchain, feature_configuration)
- for f in rust_stdlib_info.std_files
- ],
- transitive = [between_core_and_std_inputs],
- order = "topological",
- )
+
+ if _experimental_link_std_dylib(ctx):
+ # std dylib has everything so that we do not need to include all std_files
+ std_inputs = depset(
+ [cc_common.create_library_to_link(
+ actions = ctx.actions,
+ feature_configuration = feature_configuration,
+ cc_toolchain = cc_toolchain,
+ dynamic_library = rust_stdlib_info.std_dylib,
+ )],
+ )
+ else:
+ std_inputs = depset(
+ [
+ _ltl(f, ctx, cc_toolchain, feature_configuration)
+ for f in rust_stdlib_info.std_files
+ ],
+ transitive = [between_core_and_std_inputs],
+ order = "topological",
+ )
+
test_inputs = depset(
[
_ltl(f, ctx, cc_toolchain, feature_configuration)
@@ -454,6 +477,9 @@
sysroot_anchor = sysroot_anchor,
)
+def _experimental_use_cc_common_link(ctx):
+ return ctx.attr.experimental_use_cc_common_link[BuildSettingInfo].value
+
def _rust_toolchain_impl(ctx):
"""The rust_toolchain implementation
@@ -477,15 +503,14 @@
pipelined_compilation = ctx.attr._pipelined_compilation[BuildSettingInfo].value
no_std = ctx.attr._no_std[BuildSettingInfo].value
- experimental_use_cc_common_link = ctx.attr.experimental_use_cc_common_link[BuildSettingInfo].value
experimental_use_global_allocator = ctx.attr._experimental_use_global_allocator[BuildSettingInfo].value
- if experimental_use_cc_common_link:
+ if _experimental_use_cc_common_link(ctx):
if experimental_use_global_allocator and not ctx.attr.global_allocator_library:
fail("rust_toolchain.experimental_use_cc_common_link with --@rules_rust//rust/settings:experimental_use_global_allocator " +
"requires rust_toolchain.global_allocator_library to be set")
if not ctx.attr.allocator_library:
fail("rust_toolchain.experimental_use_cc_common_link requires rust_toolchain.allocator_library to be set")
- if experimental_use_global_allocator and not experimental_use_cc_common_link:
+ if experimental_use_global_allocator and not _experimental_use_cc_common_link(ctx):
fail(
"Using @rules_rust//rust/settings:experimental_use_global_allocator requires" +
"--@rules_rust//rust/settings:experimental_use_cc_common_link to be set",
@@ -639,7 +664,8 @@
_rename_first_party_crates = rename_first_party_crates,
_third_party_dir = third_party_dir,
_pipelined_compilation = pipelined_compilation,
- _experimental_use_cc_common_link = experimental_use_cc_common_link,
+ _experimental_link_std_dylib = _experimental_link_std_dylib(ctx),
+ _experimental_use_cc_common_link = _experimental_use_cc_common_link(ctx),
_experimental_use_global_allocator = experimental_use_global_allocator,
_experimental_use_coverage_metadata_files = ctx.attr._experimental_use_coverage_metadata_files[BuildSettingInfo].value,
_experimental_toolchain_generated_sysroot = ctx.attr._experimental_toolchain_generated_sysroot[IncompatibleFlagInfo].enabled,
@@ -652,6 +678,11 @@
make_variable_info,
]
+def _experimental_link_std_dylib(ctx):
+ return not is_exec_configuration(ctx) and \
+ ctx.attr.experimental_link_std_dylib[BuildSettingInfo].value and \
+ ctx.attr.rust_std[rust_common.stdlib_info].std_dylib != None
+
rust_toolchain = rule(
implementation = _rust_toolchain_impl,
fragments = ["cpp"],
@@ -702,6 +733,10 @@
),
mandatory = True,
),
+ "experimental_link_std_dylib": attr.label(
+ default = Label("@rules_rust//rust/settings:experimental_link_std_dylib"),
+ doc = "Label to a boolean build setting that controls whether whether to link libstd dynamically.",
+ ),
"experimental_use_cc_common_link": attr.label(
default = Label("//rust/settings:experimental_use_cc_common_link"),
doc = "Label to a boolean build setting that controls whether cc_common.link is used to link rust binaries.",
diff --git a/test/link_std_dylib/BUILD b/test/link_std_dylib/BUILD
new file mode 100644
index 0000000..1a92fd4
--- /dev/null
+++ b/test/link_std_dylib/BUILD
@@ -0,0 +1,3 @@
+load(":link_std_dylib_test.bzl", "link_std_dylib_test_suite")
+
+link_std_dylib_test_suite(name = "link_std_dylib_test_suite")
diff --git a/test/link_std_dylib/lib.rs b/test/link_std_dylib/lib.rs
new file mode 100644
index 0000000..734312b
--- /dev/null
+++ b/test/link_std_dylib/lib.rs
@@ -0,0 +1,7 @@
+// Analysis test shouldn't need this file.
+// This is a workaround until
+// https://github.com/bazelbuild/rules_rust/issues/2499
+// is fixed
+pub fn example_test_dep_fn() -> u32 {
+ 1
+}
diff --git a/test/link_std_dylib/link_std_dylib_test.bzl b/test/link_std_dylib/link_std_dylib_test.bzl
new file mode 100644
index 0000000..f133808
--- /dev/null
+++ b/test/link_std_dylib/link_std_dylib_test.bzl
@@ -0,0 +1,118 @@
+"""Analysis tests for experimental_link_std_dylib flag"""
+
+load("@rules_cc//cc:defs.bzl", "CcInfo")
+load("@rules_rust//rust:defs.bzl", "rust_binary", "rust_library")
+load("@rules_testing//lib:analysis_test.bzl", "analysis_test", "test_suite")
+
+# buildifier: disable=bzl-visibility
+load("//rust/private:utils.bzl", "is_std_dylib")
+
+def _test_rust_binary_impl(env, targets):
+ env.expect.that_action(targets.default_binary.actions[0]) \
+ .contains_none_of_flag_values([
+ ("--codegen", "prefer-dynamic"),
+ ])
+
+ # Make sure with @rules_rust//rust/settings:experimental_link_std_dylib,
+ # the linker flags are set up correct so that the binary dynamically links
+ # the stdlib
+ env.expect.that_action(targets.binary_with_std_dylib.actions[0]) \
+ .contains_flag_values([
+ ("--codegen", "prefer-dynamic"),
+ ])
+
+def _test_rust_binary(name):
+ rust_binary(
+ name = name + "_rust_binary",
+ srcs = ["main.rs"],
+ edition = "2021",
+ tags = ["manual"],
+ )
+
+ analysis_test(
+ name = name,
+ impl = _test_rust_binary_impl,
+ targets = {
+ "binary_with_std_dylib": name + "_rust_binary",
+ "default_binary": name + "_rust_binary",
+ },
+ attrs = {
+ "binary_with_std_dylib": {
+ "@config_settings": {
+ str(Label("@rules_rust//rust/settings:experimental_link_std_dylib")): True,
+ },
+ },
+ },
+ )
+
+def _export_static_stdlibs_in_cc_info(target):
+ linker_inputs = target[CcInfo].linking_context.linker_inputs
+ for linker_input in linker_inputs.to_list():
+ for library in linker_input.libraries:
+ if hasattr(library, "pic_static_library") and library.pic_static_library != None:
+ basename = library.pic_static_library.basename
+ if basename.startswith("libstd") and basename.endswith(".a"):
+ return True
+ return False
+
+def _export_libstd_dylib_in_cc_info(target):
+ linker_inputs = target[CcInfo].linking_context.linker_inputs
+ for linker_input in linker_inputs.to_list():
+ for library in linker_input.libraries:
+ if hasattr(library, "dynamic_library") and library.dynamic_library != None:
+ if is_std_dylib(library.dynamic_library):
+ return True
+ return False
+
+def _test_rust_library_impl(env, targets):
+ # By default, rust_library exports static stdlibs to downstream shared
+ # and binary targets to statically link
+ env.expect \
+ .that_bool(_export_static_stdlibs_in_cc_info(targets.default_rlib)) \
+ .equals(True)
+ env.expect \
+ .that_bool(_export_libstd_dylib_in_cc_info(targets.default_rlib)) \
+ .equals(False)
+
+ # With @rules_rust//rust/settings:experimental_link_std_dylib
+ # rust_library exports dylib std and does not export static stdlibs to
+ # downstream shared and binary targets to dynamically link
+ env.expect \
+ .that_bool(_export_static_stdlibs_in_cc_info(targets.rlib_with_std_dylib)) \
+ .equals(False)
+ env.expect \
+ .that_bool(_export_libstd_dylib_in_cc_info(targets.rlib_with_std_dylib)) \
+ .equals(True)
+
+def _test_rust_library(name):
+ rust_library(
+ name = name + "_rust_library",
+ srcs = ["lib.rs"],
+ edition = "2021",
+ tags = ["manual"],
+ )
+
+ analysis_test(
+ name = name,
+ impl = _test_rust_library_impl,
+ targets = {
+ "default_rlib": name + "_rust_library",
+ "rlib_with_std_dylib": name + "_rust_library",
+ },
+ attrs = {
+ "rlib_with_std_dylib": {
+ "@config_settings": {
+ str(Label("@rules_rust//rust/settings:experimental_link_std_dylib")): True,
+ },
+ },
+ },
+ )
+
+def link_std_dylib_test_suite(name):
+ test_suite(
+ name = name,
+ tests = [
+ _test_rust_binary,
+ _test_rust_library,
+ ],
+ )
diff --git a/test/link_std_dylib/main.rs b/test/link_std_dylib/main.rs
new file mode 100644
index 0000000..c5a415d
--- /dev/null
+++ b/test/link_std_dylib/main.rs
@@ -0,0 +1,7 @@
+// Analysis test shouldn't need this file.
+// This is a workaround until
+// https://github.com/bazelbuild/rules_rust/issues/2499
+// is fixed
+fn main() {
+ println!("Hello world");
+}
