[PATCH v3] scripts: generate_rust_analyzer: provide `cfg`s for `core` and `alloc`

[PATCH v3] scripts: generate_rust_analyzer: provide `cfg`s for `core` and `alloc`

[Martin Rodriguez Reboredo]

Both `core` and `alloc` have their `cfgs` (such as `no_rc`) missing
in `rust-project.json`.

To remedy this, pass the flags to `generate_rust_analyzer.py` for
them to be added to a dictionary where each key corresponds to
a crate and each value to a list of `cfg`s. The dictionary is then
used to pass the `cfg`s to each crate in the generated file (for
`core` and `alloc` only).

Suggested-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Signed-off-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
---
 rust/Makefile                     |  1 +
 scripts/generate_rust_analyzer.py | 16 ++++++++++++++--
 2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/rust/Makefile b/rust/Makefile
index f7c9a6e54c85..e5173da3b682 100644
--- a/rust/Makefile
+++ b/rust/Makefile
@@ -374,6 +374,7 @@ quiet_cmd_rustc_library = $(if $(skip_clippy),RUSTC,$(RUSTC_OR_CLIPPY_QUIET)) L
 
 rust-analyzer:
 	$(Q)$(srctree)/scripts/generate_rust_analyzer.py \
+		--cfgs='core=$(core-cfgs)' --cfgs='alloc=$(alloc-cfgs)' \
 		$(abs_srctree) $(abs_objtree) \
 		$(RUST_LIB_SRC) $(KBUILD_EXTMOD) > \
 		$(if $(KBUILD_EXTMOD),$(extmod_prefix),$(objtree))/rust-project.json
diff --git a/scripts/generate_rust_analyzer.py b/scripts/generate_rust_analyzer.py
index 848fa1ad92ba..fc52bc41d3e7 100755
--- a/scripts/generate_rust_analyzer.py
+++ b/scripts/generate_rust_analyzer.py
@@ -10,7 +10,15 @@ import os
 import pathlib
 import sys
 
-def generate_crates(srctree, objtree, sysroot_src, external_src):
+def args_crates_cfgs(cfgs):
+    crates_cfgs = {}
+    for cfg in cfgs:
+        crate, vals = cfg.split("=", 1)
+        crates_cfgs[crate] = vals.replace("--cfg", "").split()
+
+    return crates_cfgs
+
+def generate_crates(srctree, objtree, sysroot_src, external_src, cfgs):
     # Generate the configuration list.
     cfg = []
     with open(objtree / "include" / "generated" / "rustc_cfg") as fd:
@@ -24,6 +32,7 @@ def generate_crates(srctree, objtree, sysroot_src, external_src):
     # Avoid O(n^2) iterations by keeping a map of indexes.
     crates = []
     crates_indexes = {}
+    crates_cfgs = args_crates_cfgs(cfgs)
 
     def append_crate(display_name, root_module, deps, cfg=[], is_workspace_member=True, is_proc_macro=False):
         crates_indexes[display_name] = len(crates)
@@ -45,6 +54,7 @@ def generate_crates(srctree, objtree, sysroot_src, external_src):
         "core",
         sysroot_src / "core" / "src" / "lib.rs",
         [],
+        cfg=crates_cfgs.get("core", []),
         is_workspace_member=False,
     )
 
@@ -58,6 +68,7 @@ def generate_crates(srctree, objtree, sysroot_src, external_src):
         "alloc",
         srctree / "rust" / "alloc" / "lib.rs",
         ["core", "compiler_builtins"],
+        cfg=crates_cfgs.get("alloc", []),
     )
 
     append_crate(
@@ -131,6 +142,7 @@ def generate_crates(srctree, objtree, sysroot_src, external_src):
 def main():
     parser = argparse.ArgumentParser()
     parser.add_argument('--verbose', '-v', action='store_true')
+    parser.add_argument('--cfgs', action='append', default=[])
     parser.add_argument("srctree", type=pathlib.Path)
     parser.add_argument("objtree", type=pathlib.Path)
     parser.add_argument("sysroot_src", type=pathlib.Path)
@@ -143,7 +155,7 @@ def main():
     )
 
     rust_project = {
-        "crates": generate_crates(args.srctree, args.objtree, args.sysroot_src, args.exttree),
+        "crates": generate_crates(args.srctree, args.objtree, args.sysroot_src, args.exttree, args.cfgs),
         "sysroot_src": str(args.sysroot_src),
     }
 
-- 
2.41.0

[PATCH v3] scripts: generate_rust_analyzer: provide `cfg`s for `core` and `alloc`

[Martin Rodriguez Reboredo]

Both `core` and `alloc` have their `cfgs` (such as `no_rc`) missing
in `rust-project.json`.

To remedy this, pass the flags to `generate_rust_analyzer.py` for
them to be added to a dictionary where each key corresponds to
a crate and each value to a list of `cfg`s. The dictionary is then
used to pass the `cfg`s to each crate in the generated file (for
`core` and `alloc` only).

Suggested-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Signed-off-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
---
 rust/Makefile                     |  1 +
 scripts/generate_rust_analyzer.py | 16 ++++++++++++++--
 2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/rust/Makefile b/rust/Makefile
index f7c9a6e54c85..e5173da3b682 100644
--- a/rust/Makefile
+++ b/rust/Makefile
@@ -374,6 +374,7 @@ quiet_cmd_rustc_library = $(if $(skip_clippy),RUSTC,$(RUSTC_OR_CLIPPY_QUIET)) L
 
 rust-analyzer:
 	$(Q)$(srctree)/scripts/generate_rust_analyzer.py \
+		--cfgs='core=$(core-cfgs)' --cfgs='alloc=$(alloc-cfgs)' \
 		$(abs_srctree) $(abs_objtree) \
 		$(RUST_LIB_SRC) $(KBUILD_EXTMOD) > \
 		$(if $(KBUILD_EXTMOD),$(extmod_prefix),$(objtree))/rust-project.json
diff --git a/scripts/generate_rust_analyzer.py b/scripts/generate_rust_analyzer.py
index 848fa1ad92ba..fc52bc41d3e7 100755
--- a/scripts/generate_rust_analyzer.py
+++ b/scripts/generate_rust_analyzer.py
@@ -10,7 +10,15 @@ import os
 import pathlib
 import sys
 
-def generate_crates(srctree, objtree, sysroot_src, external_src):
+def args_crates_cfgs(cfgs):
+    crates_cfgs = {}
+    for cfg in cfgs:
+        crate, vals = cfg.split("=", 1)
+        crates_cfgs[crate] = vals.replace("--cfg", "").split()
+
+    return crates_cfgs
+
+def generate_crates(srctree, objtree, sysroot_src, external_src, cfgs):
     # Generate the configuration list.
     cfg = []
     with open(objtree / "include" / "generated" / "rustc_cfg") as fd:
@@ -24,6 +32,7 @@ def generate_crates(srctree, objtree, sysroot_src, external_src):
     # Avoid O(n^2) iterations by keeping a map of indexes.
     crates = []
     crates_indexes = {}
+    crates_cfgs = args_crates_cfgs(cfgs)
 
     def append_crate(display_name, root_module, deps, cfg=[], is_workspace_member=True, is_proc_macro=False):
         crates_indexes[display_name] = len(crates)
@@ -45,6 +54,7 @@ def generate_crates(srctree, objtree, sysroot_src, external_src):
         "core",
         sysroot_src / "core" / "src" / "lib.rs",
         [],
+        cfg=crates_cfgs.get("core", []),
         is_workspace_member=False,
     )
 
@@ -58,6 +68,7 @@ def generate_crates(srctree, objtree, sysroot_src, external_src):
         "alloc",
         srctree / "rust" / "alloc" / "lib.rs",
         ["core", "compiler_builtins"],
+        cfg=crates_cfgs.get("alloc", []),
     )
 
     append_crate(
@@ -131,6 +142,7 @@ def generate_crates(srctree, objtree, sysroot_src, external_src):
 def main():
     parser = argparse.ArgumentParser()
     parser.add_argument('--verbose', '-v', action='store_true')
+    parser.add_argument('--cfgs', action='append', default=[])
     parser.add_argument("srctree", type=pathlib.Path)
     parser.add_argument("objtree", type=pathlib.Path)
     parser.add_argument("sysroot_src", type=pathlib.Path)
@@ -143,7 +155,7 @@ def main():
     )
 
     rust_project = {
-        "crates": generate_crates(args.srctree, args.objtree, args.sysroot_src, args.exttree),
+        "crates": generate_crates(args.srctree, args.objtree, args.sysroot_src, args.exttree, args.cfgs),
         "sysroot_src": str(args.sysroot_src),
     }
 
-- 
2.41.0

Re: [PATCH v3] scripts: generate_rust_analyzer: provide `cfg`s for `core` and `alloc`

[Miguel Ojeda]

On Fri, Aug 4, 2023 at 7:14 PM Martin Rodriguez Reboredo
<yakoyoku@gmail.com> wrote:
>
> Suggested-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>

Thanks Martin!

I am a bit confused about the Suggested-by -- did you add it due to
the suggestion from v1 of passing variables via command-line
arguments? If so, I appreciate the gesture, but the main idea/report
(passing the missing `cfg`s for `core` and `alloc`) is yours! :)

The patch seems fine, I will test & apply it soon. If someone wants to
give it a Tested-by with rust-analyzer, that would be great too,
thanks! (note: it applies on top of `rust-next`).

Cheers,
Miguel

Re: [PATCH v3] scripts: generate_rust_analyzer: provide `cfg`s for `core` and `alloc`

[Martin Rodriguez Reboredo]

On 8/5/23 07:46, Miguel Ojeda wrote:
> On Fri, Aug 4, 2023 at 7:14 PM Martin Rodriguez Reboredo
> <yakoyoku@gmail.com> wrote:
>>
>> Suggested-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
> 
> Thanks Martin!
> 
> I am a bit confused about the Suggested-by -- did you add it due to
> the suggestion from v1 of passing variables via command-line
> arguments? If so, I appreciate the gesture, but the main idea/report
> (passing the missing `cfg`s for `core` and `alloc`) is yours! :)

Ah, it was because you suggested the commit's text, should have been
more clear about it, I thought that the "Suggested-by" was for any
suggestions in reviews, and in reality it was for suggestions for
the kernel itself. In this case I've got confused. So, because I saw
the issue with the `rust-project.json` I'd like to rescind that
"Suggested-by", though, FWIW you still get credit in the end when you
do the sign-off at merge. 😇

> The patch seems fine, I will test & apply it soon. If someone wants to
> give it a Tested-by with rust-analyzer, that would be great too,
> thanks! (note: it applies on top of `rust-next`).
> 
> Cheers,
> Miguel

If someone wants to test it, just try in your IDE to go into the
definition of some member of `core` and `alloc`, e.g. `Pin` or
`Vector`.

Re: [PATCH v3] scripts: generate_rust_analyzer: provide `cfg`s for `core` and `alloc`

[Miguel Ojeda]

On Sat, Aug 5, 2023 at 3:00 PM Martin Rodriguez Reboredo
<yakoyoku@gmail.com> wrote:
>
> Ah, it was because you suggested the commit's text, should have been
> more clear about it, I thought that the "Suggested-by" was for any
> suggestions in reviews, and in reality it was for suggestions for
> the kernel itself. In this case I've got confused. So, because I saw

If it was for the commit message suggestion from v2, then it should
not be there. In most cases you would credit those in the changelog
(in the cover letter or after the `---` line).

I will remove it when I apply it then, thanks!

Cheers,
Miguel

Re: [PATCH v3] scripts: generate_rust_analyzer: provide `cfg`s for `core` and `alloc`

[Miguel Ojeda]

On Fri, Aug 4, 2023 at 7:14 PM Martin Rodriguez Reboredo
<yakoyoku@gmail.com> wrote:
>
> Both `core` and `alloc` have their `cfgs` (such as `no_rc`) missing
> in `rust-project.json`.
>
> To remedy this, pass the flags to `generate_rust_analyzer.py` for
> them to be added to a dictionary where each key corresponds to
> a crate and each value to a list of `cfg`s. The dictionary is then
> used to pass the `cfg`s to each crate in the generated file (for
> `core` and `alloc` only).
>
> Suggested-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
> Signed-off-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>

Applied to `rust-next` -- thanks!

As discussed, I removed the Suggested-by.

Cheers,
Miguel

[PATCH v3] scripts: generate_rust_analyzer: provide `cfg`s for `core` and `alloc`

[Martin Rodriguez Reboredo]

Both `core` and `alloc` have their `cfgs` (such as `no_rc`) missing
in `rust-project.json`.

To remedy this, pass the flags to `generate_rust_analyzer.py` for
them to be added to a dictionary where each key corresponds to
a crate and each value to a list of `cfg`s. The dictionary is then
used to pass the `cfg`s to each crate in the generated file (for
`core` and `alloc` only).

Suggested-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Signed-off-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
---
 rust/Makefile                     |  1 +
 scripts/generate_rust_analyzer.py | 16 ++++++++++++++--
 2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/rust/Makefile b/rust/Makefile
index f7c9a6e54c85..e5173da3b682 100644
--- a/rust/Makefile
+++ b/rust/Makefile
@@ -374,6 +374,7 @@ quiet_cmd_rustc_library = $(if $(skip_clippy),RUSTC,$(RUSTC_OR_CLIPPY_QUIET)) L
 
 rust-analyzer:
 	$(Q)$(srctree)/scripts/generate_rust_analyzer.py \
+		--cfgs='core=$(core-cfgs)' --cfgs='alloc=$(alloc-cfgs)' \
 		$(abs_srctree) $(abs_objtree) \
 		$(RUST_LIB_SRC) $(KBUILD_EXTMOD) > \
 		$(if $(KBUILD_EXTMOD),$(extmod_prefix),$(objtree))/rust-project.json
diff --git a/scripts/generate_rust_analyzer.py b/scripts/generate_rust_analyzer.py
index 848fa1ad92ba..fc52bc41d3e7 100755
--- a/scripts/generate_rust_analyzer.py
+++ b/scripts/generate_rust_analyzer.py
@@ -10,7 +10,15 @@ import os
 import pathlib
 import sys
 
-def generate_crates(srctree, objtree, sysroot_src, external_src):
+def args_crates_cfgs(cfgs):
+    crates_cfgs = {}
+    for cfg in cfgs:
+        crate, vals = cfg.split("=", 1)
+        crates_cfgs[crate] = vals.replace("--cfg", "").split()
+
+    return crates_cfgs
+
+def generate_crates(srctree, objtree, sysroot_src, external_src, cfgs):
     # Generate the configuration list.
     cfg = []
     with open(objtree / "include" / "generated" / "rustc_cfg") as fd:
@@ -24,6 +32,7 @@ def generate_crates(srctree, objtree, sysroot_src, external_src):
     # Avoid O(n^2) iterations by keeping a map of indexes.
     crates = []
     crates_indexes = {}
+    crates_cfgs = args_crates_cfgs(cfgs)
 
     def append_crate(display_name, root_module, deps, cfg=[], is_workspace_member=True, is_proc_macro=False):
         crates_indexes[display_name] = len(crates)
@@ -45,6 +54,7 @@ def generate_crates(srctree, objtree, sysroot_src, external_src):
         "core",
         sysroot_src / "core" / "src" / "lib.rs",
         [],
+        cfg=crates_cfgs.get("core", []),
         is_workspace_member=False,
     )
 
@@ -58,6 +68,7 @@ def generate_crates(srctree, objtree, sysroot_src, external_src):
         "alloc",
         srctree / "rust" / "alloc" / "lib.rs",
         ["core", "compiler_builtins"],
+        cfg=crates_cfgs.get("alloc", []),
     )
 
     append_crate(
@@ -131,6 +142,7 @@ def generate_crates(srctree, objtree, sysroot_src, external_src):
 def main():
     parser = argparse.ArgumentParser()
     parser.add_argument('--verbose', '-v', action='store_true')
+    parser.add_argument('--cfgs', action='append', default=[])
     parser.add_argument("srctree", type=pathlib.Path)
     parser.add_argument("objtree", type=pathlib.Path)
     parser.add_argument("sysroot_src", type=pathlib.Path)
@@ -143,7 +155,7 @@ def main():
     )
 
     rust_project = {
-        "crates": generate_crates(args.srctree, args.objtree, args.sysroot_src, args.exttree),
+        "crates": generate_crates(args.srctree, args.objtree, args.sysroot_src, args.exttree, args.cfgs),
         "sysroot_src": str(args.sysroot_src),
     }
 
-- 
2.41.0

[PATCH v3] scripts: generate_rust_analyzer: provide `cfg`s for `core` and `alloc`

[Martin Rodriguez Reboredo]

Both `core` and `alloc` have their `cfgs` (such as `no_rc`) missing
in `rust-project.json`.

To remedy this, pass the flags to `generate_rust_analyzer.py` for
them to be added to a dictionary where each key corresponds to
a crate and each value to a list of `cfg`s. The dictionary is then
used to pass the `cfg`s to each crate in the generated file (for
`core` and `alloc` only).

Suggested-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Signed-off-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
---
 rust/Makefile                     |  1 +
 scripts/generate_rust_analyzer.py | 16 ++++++++++++++--
 2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/rust/Makefile b/rust/Makefile
index f7c9a6e54c85..e5173da3b682 100644
--- a/rust/Makefile
+++ b/rust/Makefile
@@ -374,6 +374,7 @@ quiet_cmd_rustc_library = $(if $(skip_clippy),RUSTC,$(RUSTC_OR_CLIPPY_QUIET)) L
 
 rust-analyzer:
 	$(Q)$(srctree)/scripts/generate_rust_analyzer.py \
+		--cfgs='core=$(core-cfgs)' --cfgs='alloc=$(alloc-cfgs)' \
 		$(abs_srctree) $(abs_objtree) \
 		$(RUST_LIB_SRC) $(KBUILD_EXTMOD) > \
 		$(if $(KBUILD_EXTMOD),$(extmod_prefix),$(objtree))/rust-project.json
diff --git a/scripts/generate_rust_analyzer.py b/scripts/generate_rust_analyzer.py
index 848fa1ad92ba..fc52bc41d3e7 100755
--- a/scripts/generate_rust_analyzer.py
+++ b/scripts/generate_rust_analyzer.py
@@ -10,7 +10,15 @@ import os
 import pathlib
 import sys
 
-def generate_crates(srctree, objtree, sysroot_src, external_src):
+def args_crates_cfgs(cfgs):
+    crates_cfgs = {}
+    for cfg in cfgs:
+        crate, vals = cfg.split("=", 1)
+        crates_cfgs[crate] = vals.replace("--cfg", "").split()
+
+    return crates_cfgs
+
+def generate_crates(srctree, objtree, sysroot_src, external_src, cfgs):
     # Generate the configuration list.
     cfg = []
     with open(objtree / "include" / "generated" / "rustc_cfg") as fd:
@@ -24,6 +32,7 @@ def generate_crates(srctree, objtree, sysroot_src, external_src):
     # Avoid O(n^2) iterations by keeping a map of indexes.
     crates = []
     crates_indexes = {}
+    crates_cfgs = args_crates_cfgs(cfgs)
 
     def append_crate(display_name, root_module, deps, cfg=[], is_workspace_member=True, is_proc_macro=False):
         crates_indexes[display_name] = len(crates)
@@ -45,6 +54,7 @@ def generate_crates(srctree, objtree, sysroot_src, external_src):
         "core",
         sysroot_src / "core" / "src" / "lib.rs",
         [],
+        cfg=crates_cfgs.get("core", []),
         is_workspace_member=False,
     )
 
@@ -58,6 +68,7 @@ def generate_crates(srctree, objtree, sysroot_src, external_src):
         "alloc",
         srctree / "rust" / "alloc" / "lib.rs",
         ["core", "compiler_builtins"],
+        cfg=crates_cfgs.get("alloc", []),
     )
 
     append_crate(
@@ -131,6 +142,7 @@ def generate_crates(srctree, objtree, sysroot_src, external_src):
 def main():
     parser = argparse.ArgumentParser()
     parser.add_argument('--verbose', '-v', action='store_true')
+    parser.add_argument('--cfgs', action='append', default=[])
     parser.add_argument("srctree", type=pathlib.Path)
     parser.add_argument("objtree", type=pathlib.Path)
     parser.add_argument("sysroot_src", type=pathlib.Path)
@@ -143,7 +155,7 @@ def main():
     )
 
     rust_project = {
-        "crates": generate_crates(args.srctree, args.objtree, args.sysroot_src, args.exttree),
+        "crates": generate_crates(args.srctree, args.objtree, args.sysroot_src, args.exttree, args.cfgs),
         "sysroot_src": str(args.sysroot_src),
     }
 
-- 
2.41.0

[PATCH v3] scripts: generate_rust_analyzer: provide `cfg`s for `core` and `alloc`

[Martin Rodriguez Reboredo]

Both `core` and `alloc` have their `cfgs` (such as `no_rc`) missing
in `rust-project.json`.

To remedy this, pass the flags to `generate_rust_analyzer.py` for
them to be added to a dictionary where each key corresponds to
a crate and each value to a list of `cfg`s. The dictionary is then
used to pass the `cfg`s to each crate in the generated file (for
`core` and `alloc` only).

Suggested-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Signed-off-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
---
 rust/Makefile                     |  1 +
 scripts/generate_rust_analyzer.py | 16 ++++++++++++++--
 2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/rust/Makefile b/rust/Makefile
index f7c9a6e54c85..e5173da3b682 100644
--- a/rust/Makefile
+++ b/rust/Makefile
@@ -374,6 +374,7 @@ quiet_cmd_rustc_library = $(if $(skip_clippy),RUSTC,$(RUSTC_OR_CLIPPY_QUIET)) L
 
 rust-analyzer:
 	$(Q)$(srctree)/scripts/generate_rust_analyzer.py \
+		--cfgs='core=$(core-cfgs)' --cfgs='alloc=$(alloc-cfgs)' \
 		$(abs_srctree) $(abs_objtree) \
 		$(RUST_LIB_SRC) $(KBUILD_EXTMOD) > \
 		$(if $(KBUILD_EXTMOD),$(extmod_prefix),$(objtree))/rust-project.json
diff --git a/scripts/generate_rust_analyzer.py b/scripts/generate_rust_analyzer.py
index 848fa1ad92ba..fc52bc41d3e7 100755
--- a/scripts/generate_rust_analyzer.py
+++ b/scripts/generate_rust_analyzer.py
@@ -10,7 +10,15 @@ import os
 import pathlib
 import sys
 
-def generate_crates(srctree, objtree, sysroot_src, external_src):
+def args_crates_cfgs(cfgs):
+    crates_cfgs = {}
+    for cfg in cfgs:
+        crate, vals = cfg.split("=", 1)
+        crates_cfgs[crate] = vals.replace("--cfg", "").split()
+
+    return crates_cfgs
+
+def generate_crates(srctree, objtree, sysroot_src, external_src, cfgs):
     # Generate the configuration list.
     cfg = []
     with open(objtree / "include" / "generated" / "rustc_cfg") as fd:
@@ -24,6 +32,7 @@ def generate_crates(srctree, objtree, sysroot_src, external_src):
     # Avoid O(n^2) iterations by keeping a map of indexes.
     crates = []
     crates_indexes = {}
+    crates_cfgs = args_crates_cfgs(cfgs)
 
     def append_crate(display_name, root_module, deps, cfg=[], is_workspace_member=True, is_proc_macro=False):
         crates_indexes[display_name] = len(crates)
@@ -45,6 +54,7 @@ def generate_crates(srctree, objtree, sysroot_src, external_src):
         "core",
         sysroot_src / "core" / "src" / "lib.rs",
         [],
+        cfg=crates_cfgs.get("core", []),
         is_workspace_member=False,
     )
 
@@ -58,6 +68,7 @@ def generate_crates(srctree, objtree, sysroot_src, external_src):
         "alloc",
         srctree / "rust" / "alloc" / "lib.rs",
         ["core", "compiler_builtins"],
+        cfg=crates_cfgs.get("alloc", []),
     )
 
     append_crate(
@@ -131,6 +142,7 @@ def generate_crates(srctree, objtree, sysroot_src, external_src):
 def main():
     parser = argparse.ArgumentParser()
     parser.add_argument('--verbose', '-v', action='store_true')
+    parser.add_argument('--cfgs', action='append', default=[])
     parser.add_argument("srctree", type=pathlib.Path)
     parser.add_argument("objtree", type=pathlib.Path)
     parser.add_argument("sysroot_src", type=pathlib.Path)
@@ -143,7 +155,7 @@ def main():
     )
 
     rust_project = {
-        "crates": generate_crates(args.srctree, args.objtree, args.sysroot_src, args.exttree),
+        "crates": generate_crates(args.srctree, args.objtree, args.sysroot_src, args.exttree, args.cfgs),
         "sysroot_src": str(args.sysroot_src),
     }
 
-- 
2.41.0