set CC and CXX and their flags in meson (#1098)

examples/third_party/mesa/BUILD.mesa.bazel

@@ -39,6 +39,12 @@ meson_with_requirements(
         },
     }),
     lib_source = ":all_srcs",
+    linkopts = select({
+        "@openssl//:msvc_compiler": [
+            "ws2_32.lib",
+        ],
+        "//conditions:default": [],
+    }),
     options = select({
         "@platforms//os:linux": {
             # Disable LLVM support, as building LLVM in rules_foreign_cc CI would drastically increase the build time

foreign_cc/meson.bzl

@@ -2,6 +2,12 @@
 
 load("//foreign_cc:utils.bzl", "full_label")
 load("//foreign_cc/built_tools:meson_build.bzl", "meson_tool")
+load(
+    "//foreign_cc/private:cc_toolchain_util.bzl",
+    "absolutize_path_in_str",
+    "get_flags_info",
+    "get_tools_info",
+)
 load(
     "//foreign_cc/private:detect_root.bzl",
     "detect_root",
@@ -61,8 +67,34 @@ def _create_meson_script(configureParameters):
     attrs = configureParameters.attrs
     inputs = configureParameters.inputs
 
+    tools = get_tools_info(ctx)
     script = pkgconfig_script(inputs.ext_build_dirs)
 
+    # CFLAGS and CXXFLAGS are also set in foreign_cc/private/cmake_script.bzl, so that meson
+    # can use the intended tools.
+    # However, they are split by meson on whitespace. For Windows it's common to have spaces in path
+    # https://github.com/mesonbuild/meson/issues/3565
+    # Skip setting them in this case.
+    if " " not in tools.cc:
+        script.append("##export_var## CC {}".format(_absolutize(ctx.workspace_name, tools.cc)))
+    if " " not in tools.cxx:
+        script.append("##export_var## CXX {}".format(_absolutize(ctx.workspace_name, tools.cxx)))
+
+    # set flags same as foreign_cc/private/cc_toolchain_util.bzl
+    # cannot use get_flags_info() because bazel adds additional flags that
+    # aren't compatible with compiler or linker above
+    copts = (ctx.fragments.cpp.copts + ctx.fragments.cpp.conlyopts + getattr(ctx.attr, "copts", [])) or []
+    cxxopts = (ctx.fragments.cpp.copts + ctx.fragments.cpp.cxxopts + getattr(ctx.attr, "copts", [])) or []
+
+    if copts:
+        script.append("##export_var## CFLAGS \"{}\"".format(" ".join(copts).replace("\"", "'")))
+    if cxxopts:
+        script.append("##export_var## CXXFLAGS \"{}\"".format(" ".join(cxxopts).replace("\"", "'")))
+
+    flags = get_flags_info(ctx)
+    if flags.cxx_linker_executable:
+        script.append("##export_var## LDFLAGS \"{}\"".format(" ".join(flags.cxx_linker_executable).replace("\"", "'")))
+
     script.append("##export_var## CMAKE {}".format(attrs.cmake_path))
     script.append("##export_var## NINJA {}".format(attrs.ninja_path))
     script.append("##export_var## PKG_CONFIG {}".format(attrs.pkg_config_path))
@@ -201,3 +233,9 @@ def meson_with_requirements(name, requirements, **kwargs):
         toolchain = full_label("built_meson_toolchain_for_{}".format(name)),
         **kwargs
     )
+
+def _absolutize(workspace_name, text, force = False):
+    if text.strip(" ").startswith("C:") or text.strip(" ").startswith("c:"):
+        return "\"{}\"".format(text)
+
+    return absolutize_path_in_str(workspace_name, "$EXT_BUILD_ROOT/", text, force)

foreign_cc/private/framework/helpers.bzl

@@ -191,6 +191,7 @@ def do_function_call(text, shell_context):
         return replace_exports(after, shell_context)
 
     arguments = split_arguments(after.strip(" ")) if after else []
+
     return call_shell(shell_context, funname, *arguments)
 
 # buildifier: disable=function-docstring
@@ -199,22 +200,28 @@ def split_arguments(text):
     current = text.strip(" ")
 
     for _ in range(1, 2147483647):
+        current = current.strip(" ")
         if not current:
             break
 
         # we are ignoring escaped quotes
-        (before, separator, after) = current.partition("\"")
-        if not separator:
-            parts += current.split(" ")
+        s_quote = current.find("\"")
+        if s_quote < 0:
+            for e in current.split(" "):
+                if len(e) > 0:
+                    parts.append(e)
             break
-        (quoted, separator2, after2) = after.partition("\"")
-        if not separator2:
+
+        e_quote = current.find("\"", s_quote + 1)
+        if e_quote < 0:
             fail("Incorrect quoting in fragment: {}".format(current))
 
-        before = before.strip(" ")
-        if before:
+        # backtrack to first space, from here to e_quote is a token
+        e_before = current.rfind(" ", 0, s_quote)
+        if e_before >= 0:
+            before = current[0:e_before].strip(" ")
             parts += before.split(" ")
-        parts.append("\"" + quoted + "\"")
-        current = after2
+        parts.append(current[e_before + 1:e_quote + 1])
+        current = current[e_quote + 1:]
 
     return parts

test/convert_shell_script_test.bzl

@@ -84,6 +84,7 @@ def _split_arguments_test(ctx):
         " 1 2 3": ["1", "2", "3"],
         " usual \"quoted argument\"": ["usual", "\"quoted argument\""],
         "1 2": ["1", "2"],
+        "var -flag1=\"redacted\" -flag2=\"redacted\"": ["var", "-flag1=\"redacted\"", "-flag2=\"redacted\""],
     }
     for case in cases:
         result = split_arguments(case)