[PATCH] 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>
---
 scripts/generate_rust_analyzer.py | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/scripts/generate_rust_analyzer.py b/scripts/generate_rust_analyzer.py
index ecc7ea9a4dcf..8bfadd688ebc 100755
--- a/scripts/generate_rust_analyzer.py
+++ b/scripts/generate_rust_analyzer.py
@@ -9,6 +9,24 @@ import logging
 import pathlib
 import sys
 
+def makefile_crate_cfgs(makefile):
+    # Get configurations from a Makefile.
+    cfgs = {}
+    with open(makefile) as fd:
+        for line in fd:
+            if line.endswith("-cfgs = \\\n"):
+                crate = line.replace("-cfgs = \\\n", "")
+                cfg = []
+                for l in map(lambda l: l.strip(), fd):
+                    if not l:
+                        cfgs[crate] = cfg
+                        break
+                    l = l.replace("--cfg ", "")
+                    l = l.replace(" \\", "")
+                    cfg.append(l)
+
+    return cfgs
+
 def generate_crates(srctree, objtree, sysroot_src):
     # Generate the configuration list.
     cfg = []
@@ -24,6 +42,8 @@ def generate_crates(srctree, objtree, sysroot_src):
     crates = []
     crates_indexes = {}
 
+    makefile_cfgs = makefile_crate_cfgs(srctree / "rust" / "Makefile")
+
     def append_crate(display_name, root_module, deps, cfg=[], is_workspace_member=True, is_proc_macro=False):
         crates_indexes[display_name] = len(crates)
         crates.append({
@@ -44,6 +64,7 @@ def generate_crates(srctree, objtree, sysroot_src):
         "core",
         sysroot_src / "core" / "src" / "lib.rs",
         [],
+        cfg=makefile_cfgs.get("core", []),
         is_workspace_member=False,
     )
 
@@ -57,6 +78,7 @@ def generate_crates(srctree, objtree, sysroot_src):
         "alloc",
         srctree / "rust" / "alloc" / "lib.rs",
         ["core", "compiler_builtins"],
+        cfg=makefile_cfgs.get("alloc", []),
     )
 
     append_crate(
-- 
2.39.2