[PATCH v2] scripts: read cfgs from Makefile for rust-analyzer

[Martin Rodriguez Reboredo <yakoyoku@gmail.com>]

Both `core` and `alloc` had their `cfgs` missing in `rust-project.json`,
to remedy this `generate_rust_analyzer.py` scans the Makefile from
inside the `rust` directory for them to be added to a dictionary that
each key corresponds to a crate and each value, to an array of `cfgs`.

Signed-off-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
---
v1 -> v2:
- Read values from command line arguments

 rust/Makefile                     |  4 +++-
 scripts/generate_rust_analyzer.py | 16 ++++++++++++++--
 2 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/rust/Makefile b/rust/Makefile
index 7c9d9f11aec5..6234f5b70aee 100644
--- a/rust/Makefile
+++ b/rust/Makefile
@@ -373,7 +373,9 @@ quiet_cmd_rustc_library = $(if $(skip_clippy),RUSTC,$(RUSTC_OR_CLIPPY_QUIET)) L
 	$(if $(rustc_objcopy),;$(OBJCOPY) $(rustc_objcopy) $@)
 
 rust-analyzer:
-	$(Q)$(srctree)/scripts/generate_rust_analyzer.py $(srctree) $(objtree) \
+	$(Q)$(srctree)/scripts/generate_rust_analyzer.py \
+		--cfgs='core=$(core-cfgs)' --cfgs='alloc=$(alloc-cfgs)' \
+		$(srctree) $(objtree) \
 		$(RUST_LIB_SRC) > $(objtree)/rust-project.json
 
 redirect-intrinsics = \
diff --git a/scripts/generate_rust_analyzer.py b/scripts/generate_rust_analyzer.py
index 946e250c1b2a..5a850f055609 100755
--- a/scripts/generate_rust_analyzer.py
+++ b/scripts/generate_rust_analyzer.py
@@ -9,7 +9,15 @@ import logging
 import pathlib
 import sys
 
-def generate_crates(srctree, objtree, sysroot_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, cfgs):
     # Generate the configuration list.
     cfg = []
     with open(objtree / "include" / "generated" / "rustc_cfg") as fd:
@@ -23,6 +31,7 @@ def generate_crates(srctree, objtree, sysroot_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)
@@ -44,6 +53,7 @@ def generate_crates(srctree, objtree, sysroot_src):
         "core",
         sysroot_src / "core" / "src" / "lib.rs",
         [],
+        cfg=crates_cfgs.get("core", []),
         is_workspace_member=False,
     )
 
@@ -57,6 +67,7 @@ def generate_crates(srctree, objtree, sysroot_src):
         "alloc",
         srctree / "rust" / "alloc" / "lib.rs",
         ["core", "compiler_builtins"],
+        cfg=crates_cfgs.get("alloc", []),
     )
 
     append_crate(
@@ -123,6 +134,7 @@ def generate_crates(srctree, objtree, sysroot_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)
@@ -134,7 +146,7 @@ def main():
     )
 
     rust_project = {
-        "crates": generate_crates(args.srctree, args.objtree, args.sysroot_src),
+        "crates": generate_crates(args.srctree, args.objtree, args.sysroot_src, args.cfgs),
         "sysroot_src": str(args.sysroot_src),
     }
 
-- 
2.40.1