rules_cc issue while using for cross compilation.

[dommatib]

Description of the problem:
I'm using rules_cc to cross compile the c++ code. while i configure the bazel workspace with rules_cc repo, it fails to download.
Below is the Example:
Workspace file:
load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")

http_archive(
name = "rules_cc",
urls = ["https://github.com/bazelbuild/rules_cc/releases/download/0.0.9/rules_cc-0.0.9.tar.gz"],
sha256 = "2037875b9a4456dce4a79d112a8ae885bbc4aad968e6587dca6e64f3a0900cdf",
strip_prefix = "rules_cc-0.0.9",
)

load("@rules_cc//cc:configs.bzl", "cc_autoconf")

cc_autoconf(name = "local_config_cc")

load("@bazel_toolchains//rules:envs.bzl", "bazel_toolchain")

bazel_toolchain(
name = "x86_64-linux",
exec_compatible_with = [
"@platforms//os:linux",
"@platforms//cpu:x86_64",
],
target_compatible_with = [
"@platforms//os:linux",
"@platforms//cpu:x86_64",
],
toolchain = ":cc-compiler-x86_64-linux",
toolchain_type = "@bazel_tools//tools/cpp:toolchain_type",
)

bazel_toolchain(
name = "x86_64-windows",
exec_compatible_with = [
"@platforms//os:linux",
"@platforms//cpu:x86_64",
],
target_compatible_with = [
"@platforms//os:windows",
"@platforms//cpu:x86_64",
],
toolchain = ":cc-compiler-x86_64-windows",
toolchain_type = "@bazel_tools//tools/cpp:toolchain_type",
)

cc_toolchain_config(
name = "cc-compiler-x86_64-linux",
cpu = "k8",
compiler = "gcc",
host_system_name = "x86_64-unknown-linux-gnu",
target_system_name = "x86_64-unknown-linux-gnu",
target_libc = "glibc_2.24",
)

cc_toolchain_config(
name = "cc-compiler-x86_64-windows",
cpu= "k8",
compiler = "msvc-cl",
host_system_name = "x86_64-unknown-linux-gnu",
target_system_name = "x86_64-unknown-windows",
target_libc = "msvcrt",
)
BUILD FILE:
#load("@rules_cc//cc:cc_toolchain_config.bzl", "cc_toolchain_config")

#exports_files(["cc_toolchain_config.bzl"])

cc_library(
name = "hello_greet",
srcs = ["hello_greet.cc"],
hdrs = ["hello_greet.h"],
)

cc_shared_library(
name = "hello_greet_shared",
deps = [":hello_greet"],
)

cc_binary(
name = "hello_world_linux",
srcs = ["hello_world.cc"],
deps = [":hello_greet", ":hello_greet_shared"],
toolchains = ["@linux_toolchain"],
)

cc_binary(
name = "hello_world_windows",
srcs = ["hello_world.cc"],
deps = [":hello_greet", ":hello_greet_shared"],
toolchains = ["@windows_toolchain"],
)

cc_toolchain_config(
name = "linux_toolchain",
toolchain_identifier = "linux",
compiler = "gcc",
target_libc = "glibc",
target_cpu = "k8",
)

cc_toolchain_config(
name = "windows_toolchain",
toolchain_identifier = "windows",
compiler = "cl.exe",
target_libc = "msvcrt",
target_cpu = "x64_windows",
)
bazel.rc file
build:windows --copt=-DWIN32
build:windows --cxxopt=-std=c++14

build:linux --copt=-DLINUX
build:linux --cxxopt=-std=c++14

build:windows --cpu=x64_windows
build:linux --cpu=x64_linux

build:windows --compilation_mode=dbg
build:windows --compilation_mode=opt

build:linux --compilation_mode=dbg
build:linux --compilation_mode=opt

build:dbg --copt=-g
build:dbg -c dbg
build:opt --copt=-O3
build:opt --copt=-DNDEBUG
build:opt -c opt

Translation units to Build:

hello_greet.h
#ifndef LIB_HELLO_GREET_H_
#define LIB_HELLO_GREET_H_

#include

std::string get_greet(const std::string &thing);

#endif

hello_greet.cc
#include "hello_greet.h"
#include

std::string get_greet(const std::string& world) {
return "Hello " + world;
}

hello_world.cc

#include "hello_greet.h"
#include
#include

int main(int argc, char** argv) {
std::cout << get_greet("world") << std::endl;
return 0;
}

Configured the WORKSPACE file with rules_cc this should fetch the code from git and the build file is configured for cross compiled translation units (Linux & Windows) by loading rules_cc and set for cross compilation for windows and linux

ERROR: Error computing the main repository mapping: Every .bzl file must have a corresponding package, but '@@rules_cc//cc:configs.bzl' does not have one. Please create a BUILD file in the same or any parent directory. Note that this BUILD file does not need to do anything except exist.

The above error indicates ruless_cc//cc:configs.bzl is missing since the git download didn't happen because the same rules_cc is not downloaded .
As per the above error the downloaded rules_cc should be under external/rules_cc/cc/empty build file (to be created )
Manually downloaded the repo and kept under same path external/rules_cc/cc/build
Already build file exists but its still asking to create one BUILD file and add below package and export _files for configs.bzl as its missing from the repo
package(default_visibility = ["//visibility:public"])
exports_files(["configs.bzl"])

Bazel version used: bazel version 7.0.0
Debain version used: Debian GNU/Linux rodete

Let me know if you need any more information

[comius]

Bazel 7.0.0 has by default enabled bzlmod and from your example it seems you're using WORKSPACE file, which is not read. You can disable bzlmod with --nobzlmod or even better, write a MODULE.bazel with dependency to rules_cc.