static DeclarationAvailability calculateRequiredGuard(const Declaration& declaration) {
// To avoid redundant macro guards, the availability calculated by this function is the set
// difference of 'targets marked-available' from 'targets the declaration is visible in'.
// For example, a declaration that is visible always and introduced in 9 would return introduced
// in 9, but the same declaration, except only visible in 9+ would return an empty
// DeclarationAvailability.
// This currently only handles __INTRODUCED_IN.
// TODO: Do the same for __REMOVED_IN.
int global_min_api_visible = 0;
ArchMap<int> arch_visibility;
for (const auto& it : declaration.availability) {
const CompilationType& type = it.first;
if (global_min_api_visible == 0 || global_min_api_visible > type.api_level) {
global_min_api_visible = type.api_level;
}
if (arch_visibility[type.arch] == 0 || arch_visibility[type.arch] > type.api_level) {
arch_visibility[type.arch] = type.api_level;
}
}
DeclarationAvailability decl_av;
if (!declaration.calculateAvailability(&decl_av)) {
fprintf(stderr, "versioner: failed to calculate availability while preprocessing:\n");
declaration.dump("", stderr, 2);
exit(1);
}
D("Calculating required guard for %s:\n", declaration.name.c_str());
D(" Declaration availability: %s\n", to_string(decl_av).c_str());
if (verbose) {
std::string arch_visibility_str;
for (Arch arch : supported_archs) {
if (arch_visibility[arch] != 0) {
arch_visibility_str += to_string(arch);
arch_visibility_str += ": ";
arch_visibility_str += std::to_string(arch_visibility[arch]);
arch_visibility_str += ", ";
}
}
if (!arch_visibility_str.empty()) {
arch_visibility_str.resize(arch_visibility_str.size() - 2);
}
D(" Declaration visibility: global = %d, arch = %s\n", global_min_api_visible,
arch_visibility_str.c_str());
}
DeclarationAvailability result = decl_av;
if (result.global_availability.introduced <= global_min_api_visible) {
result.global_availability.introduced = 0;
}
for (Arch arch : supported_archs) {
if (result.arch_availability[arch].introduced <= arch_visibility[arch]) {
result.arch_availability[arch].introduced = 0;
}
}
D(" Calculated result: %s\n", to_string(result).c_str());
D("\n");
return result;
}
