https://github.com/Kitware/CMake
Tip revision: 25d2850c190ba915a7527a29dda6efe61be901f0 authored by Brad King on 21 March 2024, 13:32:22 UTC
CMake 3.29.0
CMake 3.29.0
Tip revision: 25d2850
cmCxxModuleMapper.cxx
/* Distributed under the OSI-approved BSD 3-Clause License. See accompanying
file Copyright.txt or https://cmake.org/licensing for details. */
#include "cmCxxModuleMapper.h"
#include <cassert>
#include <cstddef>
#include <set>
#include <sstream>
#include <string>
#include <utility>
#include <vector>
#include <cm/string_view>
#include <cmext/string_view>
#include "cmScanDepFormat.h"
#include "cmStringAlgorithms.h"
#include "cmSystemTools.h"
CxxBmiLocation::CxxBmiLocation() = default;
CxxBmiLocation::CxxBmiLocation(std::string path)
: BmiLocation(std::move(path))
{
}
CxxBmiLocation CxxBmiLocation::Unknown()
{
return {};
}
CxxBmiLocation CxxBmiLocation::Private()
{
return { std::string{} };
}
CxxBmiLocation CxxBmiLocation::Known(std::string path)
{
return { std::move(path) };
}
bool CxxBmiLocation::IsKnown() const
{
return this->BmiLocation.has_value();
}
bool CxxBmiLocation::IsPrivate() const
{
if (auto const& loc = this->BmiLocation) {
return loc->empty();
}
return false;
}
std::string const& CxxBmiLocation::Location() const
{
if (auto const& loc = this->BmiLocation) {
return *loc;
}
static std::string empty;
return empty;
}
CxxBmiLocation CxxModuleLocations::BmiGeneratorPathForModule(
std::string const& logical_name) const
{
auto bmi_loc = this->BmiLocationForModule(logical_name);
if (bmi_loc.IsKnown() && !bmi_loc.IsPrivate()) {
bmi_loc =
CxxBmiLocation::Known(this->PathForGenerator(bmi_loc.Location()));
}
return bmi_loc;
}
namespace {
struct TransitiveUsage
{
TransitiveUsage(std::string name, std::string location, LookupMethod method)
: LogicalName(std::move(name))
, Location(std::move(location))
, Method(method)
{
}
std::string LogicalName;
std::string Location;
LookupMethod Method;
};
std::vector<TransitiveUsage> GetTransitiveUsages(
CxxModuleLocations const& loc, std::vector<cmSourceReqInfo> const& required,
CxxModuleUsage const& usages)
{
std::set<std::string> transitive_usage_directs;
std::set<std::string> transitive_usage_names;
std::vector<TransitiveUsage> all_usages;
for (auto const& r : required) {
auto bmi_loc = loc.BmiGeneratorPathForModule(r.LogicalName);
if (bmi_loc.IsKnown()) {
all_usages.emplace_back(r.LogicalName, bmi_loc.Location(), r.Method);
transitive_usage_directs.insert(r.LogicalName);
// Insert transitive usages.
auto transitive_usages = usages.Usage.find(r.LogicalName);
if (transitive_usages != usages.Usage.end()) {
transitive_usage_names.insert(transitive_usages->second.begin(),
transitive_usages->second.end());
}
}
}
for (auto const& transitive_name : transitive_usage_names) {
if (transitive_usage_directs.count(transitive_name)) {
continue;
}
auto module_ref = usages.Reference.find(transitive_name);
if (module_ref != usages.Reference.end()) {
all_usages.emplace_back(transitive_name, module_ref->second.Path,
module_ref->second.Method);
}
}
return all_usages;
}
std::string CxxModuleMapContentClang(CxxModuleLocations const& loc,
cmScanDepInfo const& obj,
CxxModuleUsage const& usages)
{
std::stringstream mm;
// Clang's command line only supports a single output. If more than one is
// expected, we cannot make a useful module map file.
if (obj.Provides.size() > 1) {
return {};
}
// A series of flags which tell the compiler where to look for modules.
for (auto const& p : obj.Provides) {
auto bmi_loc = loc.BmiGeneratorPathForModule(p.LogicalName);
if (bmi_loc.IsKnown()) {
// Force the TU to be considered a C++ module source file regardless of
// extension.
mm << "-x c++-module\n";
mm << "-fmodule-output=" << bmi_loc.Location() << '\n';
break;
}
}
auto all_usages = GetTransitiveUsages(loc, obj.Requires, usages);
for (auto const& usage : all_usages) {
mm << "-fmodule-file=" << usage.LogicalName << '=' << usage.Location
<< '\n';
}
return mm.str();
}
std::string CxxModuleMapContentGcc(CxxModuleLocations const& loc,
cmScanDepInfo const& obj)
{
std::stringstream mm;
// Documented in GCC's documentation. The format is a series of
// lines with a module name and the associated filename separated
// by spaces. The first line may use `$root` as the module name
// to specify a "repository root". That is used to anchor any
// relative paths present in the file (CMake should never
// generate any).
// Write the root directory to use for module paths.
mm << "$root " << loc.RootDirectory << '\n';
for (auto const& p : obj.Provides) {
auto bmi_loc = loc.BmiGeneratorPathForModule(p.LogicalName);
if (bmi_loc.IsKnown()) {
mm << p.LogicalName << ' ' << bmi_loc.Location() << '\n';
}
}
for (auto const& r : obj.Requires) {
auto bmi_loc = loc.BmiGeneratorPathForModule(r.LogicalName);
if (bmi_loc.IsKnown()) {
mm << r.LogicalName << ' ' << bmi_loc.Location() << '\n';
}
}
return mm.str();
}
std::string CxxModuleMapContentMsvc(CxxModuleLocations const& loc,
cmScanDepInfo const& obj,
CxxModuleUsage const& usages)
{
std::stringstream mm;
// A response file of `-reference NAME=PATH` arguments.
// MSVC's command line only supports a single output. If more than one is
// expected, we cannot make a useful module map file.
if (obj.Provides.size() > 1) {
return {};
}
auto flag_for_method = [](LookupMethod method) -> cm::static_string_view {
switch (method) {
case LookupMethod::ByName:
return "-reference"_s;
case LookupMethod::IncludeAngle:
return "-headerUnit:angle"_s;
case LookupMethod::IncludeQuote:
return "-headerUnit:quote"_s;
}
assert(false && "unsupported lookup method");
return ""_s;
};
for (auto const& p : obj.Provides) {
if (p.IsInterface) {
mm << "-interface\n";
} else {
mm << "-internalPartition\n";
}
auto bmi_loc = loc.BmiGeneratorPathForModule(p.LogicalName);
if (bmi_loc.IsKnown()) {
mm << "-ifcOutput " << bmi_loc.Location() << '\n';
}
}
auto all_usages = GetTransitiveUsages(loc, obj.Requires, usages);
for (auto const& usage : all_usages) {
auto flag = flag_for_method(usage.Method);
mm << flag << ' ' << usage.LogicalName << '=' << usage.Location << '\n';
}
return mm.str();
}
}
bool CxxModuleUsage::AddReference(std::string const& logical,
std::string const& loc, LookupMethod method)
{
auto r = this->Reference.find(logical);
if (r != this->Reference.end()) {
auto& ref = r->second;
if (ref.Path == loc && ref.Method == method) {
return true;
}
auto method_name = [](LookupMethod m) -> cm::static_string_view {
switch (m) {
case LookupMethod::ByName:
return "by-name"_s;
case LookupMethod::IncludeAngle:
return "include-angle"_s;
case LookupMethod::IncludeQuote:
return "include-quote"_s;
}
assert(false && "unsupported lookup method");
return ""_s;
};
cmSystemTools::Error(cmStrCat("Disagreement of the location of the '",
logical,
"' module. "
"Location A: '",
ref.Path, "' via ", method_name(ref.Method),
"; "
"Location B: '",
loc, "' via ", method_name(method), "."));
return false;
}
auto& ref = this->Reference[logical];
ref.Path = loc;
ref.Method = method;
return true;
}
cm::static_string_view CxxModuleMapExtension(
cm::optional<CxxModuleMapFormat> format)
{
if (format) {
switch (*format) {
case CxxModuleMapFormat::Clang:
return ".pcm"_s;
case CxxModuleMapFormat::Gcc:
return ".gcm"_s;
case CxxModuleMapFormat::Msvc:
return ".ifc"_s;
}
}
return ".bmi"_s;
}
std::set<std::string> CxxModuleUsageSeed(
CxxModuleLocations const& loc, std::vector<cmScanDepInfo> const& objects,
CxxModuleUsage& usages, bool& private_usage_found)
{
// Track inner usages to populate usages from internal bits.
//
// This is a map of modules that required some other module that was not
// found to those that were not found.
std::map<std::string, std::set<std::string>> internal_usages;
std::set<std::string> unresolved;
for (cmScanDepInfo const& object : objects) {
// Add references for each of the provided modules.
for (auto const& p : object.Provides) {
auto bmi_loc = loc.BmiGeneratorPathForModule(p.LogicalName);
if (bmi_loc.IsKnown()) {
// XXX(cxx-modules): How to support header units?
usages.AddReference(p.LogicalName, bmi_loc.Location(),
LookupMethod::ByName);
}
}
// For each requires, pull in what is required.
for (auto const& r : object.Requires) {
// Find the required name in the current target.
auto bmi_loc = loc.BmiGeneratorPathForModule(r.LogicalName);
if (bmi_loc.IsPrivate()) {
cmSystemTools::Error(
cmStrCat("Unable to use module '", r.LogicalName,
"' as it is 'PRIVATE' and therefore not accessible outside "
"of its owning target."));
private_usage_found = true;
continue;
}
// Find transitive usages.
auto transitive_usages = usages.Usage.find(r.LogicalName);
for (auto const& p : object.Provides) {
auto& this_usages = usages.Usage[p.LogicalName];
// Add the direct usage.
this_usages.insert(r.LogicalName);
if (transitive_usages == usages.Usage.end() ||
internal_usages.find(r.LogicalName) != internal_usages.end()) {
// Mark that we need to update transitive usages later.
if (bmi_loc.IsKnown()) {
internal_usages[p.LogicalName].insert(r.LogicalName);
}
} else {
// Add the transitive usage.
this_usages.insert(transitive_usages->second.begin(),
transitive_usages->second.end());
}
}
if (bmi_loc.IsKnown()) {
usages.AddReference(r.LogicalName, bmi_loc.Location(), r.Method);
}
}
}
// While we have internal usages to manage.
while (!internal_usages.empty()) {
size_t starting_size = internal_usages.size();
// For each internal usage.
for (auto usage = internal_usages.begin(); usage != internal_usages.end();
/* see end of loop */) {
auto& this_usages = usages.Usage[usage->first];
for (auto use = usage->second.begin(); use != usage->second.end();
/* see end of loop */) {
// Check if this required module uses other internal modules; defer
// if so.
if (internal_usages.count(*use)) {
// Advance the iterator.
++use;
continue;
}
auto transitive_usages = usages.Usage.find(*use);
if (transitive_usages != usages.Usage.end()) {
this_usages.insert(transitive_usages->second.begin(),
transitive_usages->second.end());
}
// Remove the entry and advance the iterator.
use = usage->second.erase(use);
}
// Erase the entry if it doesn't have any remaining usages.
if (usage->second.empty()) {
usage = internal_usages.erase(usage);
} else {
++usage;
}
}
// Check that at least one usage was resolved.
if (starting_size == internal_usages.size()) {
// Nothing could be resolved this loop; we have a cycle, so record the
// cycle and exit.
for (auto const& usage : internal_usages) {
unresolved.insert(usage.first);
}
break;
}
}
return unresolved;
}
std::string CxxModuleMapContent(CxxModuleMapFormat format,
CxxModuleLocations const& loc,
cmScanDepInfo const& obj,
CxxModuleUsage const& usages)
{
switch (format) {
case CxxModuleMapFormat::Clang:
return CxxModuleMapContentClang(loc, obj, usages);
case CxxModuleMapFormat::Gcc:
return CxxModuleMapContentGcc(loc, obj);
case CxxModuleMapFormat::Msvc:
return CxxModuleMapContentMsvc(loc, obj, usages);
}
assert(false);
return {};
}