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Diffstat (limited to 'libbuild2/cc/compiledb.hxx')
| -rw-r--r-- | libbuild2/cc/compiledb.hxx | 236 |
1 files changed, 236 insertions, 0 deletions
diff --git a/libbuild2/cc/compiledb.hxx b/libbuild2/cc/compiledb.hxx new file mode 100644 index 0000000..8288cf5 --- /dev/null +++ b/libbuild2/cc/compiledb.hxx @@ -0,0 +1,236 @@ +// file : libbuild2/cc/compiledb.hxx -*- C++ -*- +// license : MIT; see accompanying LICENSE file + +#ifndef LIBBUILD2_CC_COMPILEDB_HXX +#define LIBBUILD2_CC_COMPILEDB_HXX + +#include <unordered_map> + +#ifndef BUILD2_BOOTSTRAP +# include <libbutl/json/serializer.hxx> +#endif + +#include <libbuild2/types.hxx> +#include <libbuild2/utility.hxx> + +#include <libbuild2/target.hxx> +#include <libbuild2/action.hxx> +#include <libbuild2/context.hxx> + +namespace build2 +{ + namespace cc + { + using compiledb_name_filter = vector<pair<optional<string>, bool>>; + using compiledb_type_filter = vector<pair<optional<string>, string>>; + + class compiledb + { + public: + // Match callback where we confirm an entry in the database and also + // signal whether it has changes (based on change tracking in depdb). + // Return true to force compilation of this target and thus make sure + // the below execute() is called (unless something before that failed). + // + // Besides noticing changes, this callback is also necessary to notice + // and delete entries that should no longer be in the database (e.g., a + // source file was removed from the project). + // + // Note that output is either obj*{}, bmi*{}, of hbmi*{}. + // + static bool + match (const scope& bs, + const file& output, const path& output_path, + const file& input, + bool changed); + + // Execute callback where we insert or update an entry in the database. + // + // The {relo, abso}, and {relm, absm} pairs are used to "untranslate" + // relative paths to absolute. Specifically, any argument that has rel? + // as a prefix has this prefix replaced with the corresponding abs?. + // Note that this means we won't be able to handle old MSVC and + // clang-cl, which don't support the `/F?: <path>` form, only + // `/F?<path>`. Oh, well. Note also that either relo or relm (but not + // both) could be empty if unused. + // + // Note that we assume the source file is always absolute and is the + // last argument. + // + // Why do we want absolute paths? That's a good question. Our initial + // plan was to compare command lines in order to detect when we need to + // update the database. And if those changed with every change of CWD, + // that would be of little use. But then we realized we could do better + // by using depdb to detect changes. So now we actually don't have a + // need to get rid of the relative paths in the command line. But seeing + // that we already have it, let's keep it for now in case it makes a + // different to some broken/legacy consumers. Note also that C++ module + // name-to-BMI mapping is not untranslated (see append_module_options()). + // + static void + execute (const scope& bs, + const file& output, const path& output_path, + const file& input, const path& input_path, + const process_path& cpath, const cstrings& args, + const path& relo, const path& abso, + const path& relm, const path& absm); + + public: + using path_type = build2::path; + + string name; + path_type path; + + // The path is expected to be absolute and normalized or empty if the + // name is `-` (stdout). + // + compiledb (string n, path_type p) + : name (move (n)), path (move (p)) + { + } + + virtual void + pre (context&) = 0; + + virtual bool + match (const file& output, const path_type& output_path, + bool changed) = 0; + + virtual void + execute (const file& output, const path_type& output_path, + const file& input, const path_type& input_path, + const process_path& cpath, const cstrings& args, + const path_type& relo, const path_type& abso, + const path_type& relm, const path_type& absm) = 0; + + virtual void + post (context&, const action_targets&, bool failed) = 0; + + virtual + ~compiledb (); + }; + + using compiledb_set = vector<unique_ptr<compiledb>>; + + // Populated by core_config_init() during serial load. + // + extern compiledb_set compiledbs; + + // Context operation callbacks. + // + void + compiledb_pre (context&, action, const action_targets&); + + void + compiledb_post (context&, action, const action_targets&, bool failed); + +#ifndef BUILD2_BOOTSTRAP + + // Implementation that writes to stdout. + // + // Note that this implementation forces compilation of all the targets for + // which it is called to make sure their entries are in the database. So + // typically used in the dry run mode. + // + class compiledb_stdout: public compiledb + { + public: + // The path is expected to be empty. + // + explicit + compiledb_stdout (string name); + + virtual void + pre (context&) override; + + virtual bool + match (const file& output, const path_type& output_path, + bool changed) override; + + virtual void + execute (const file& output, const path_type& output_path, + const file& input, const path_type& input_path, + const process_path& cpath, const cstrings& args, + const path_type& relo, const path_type& abso, + const path_type& relm, const path_type& absm) override; + + virtual void + post (context&, const action_targets&, bool failed) override; + + private: + mutex mutex_; + enum class state {init, empty, full, failed} state_; + size_t nesting_; + butl::json::stream_serializer js_; + }; + + // Implementation that maintains a file. + // + class compiledb_file: public compiledb + { + public: + compiledb_file (string name, path_type path); + + virtual void + pre (context&) override; + + virtual bool + match (const file& output, const path_type& output_path, + bool changed) override; + + virtual void + execute (const file& output, const path_type& output_path, + const file& input, const path_type& input_path, + const process_path& cpath, const cstrings& args, + const path_type& relo, const path_type& abso, + const path_type& relm, const path_type& absm) override; + + virtual void + post (context&, const action_targets&, bool failed) override; + + private: + mutex mutex_; + enum class state {closed, open, failed} state_; + size_t nesting_; + + // We want to optimize the performance for the incremental update case + // where only a few files will be recompiled and most of the time there + // will be no change in the command line, which means we won't need to + // rewrite the file. + // + // As a result, our in-memory representation is a hashmap (we could have + // thousands of entries) of absolute and normalized output file paths + // (stored as strings for lookup efficiency) to their serialized JSON + // text lines plus the status: absent, present, changed, or missing + // (entry should be there but is not). This way we don't waste + // (completely) parsing (and re-serializing) each line knowing that we + // won't need to touch most of them. + // + // In fact, we could have gone even further and used a sorted vector + // since insertions will be rare in this case. But we will need to + // lookup every entry on each update, so it's unclear this is a win. + // + enum class entry_status {absent, present, changed, missing}; + + struct entry + { + entry_status status; + string json; + }; + + using map_type = std::unordered_map<string, entry>; + map_type db_; + + // Number/presence of various entries in the database (used to determine + // whether we need to update the file without iterating over all the + // entries). + // + size_t absent_; // Number of absent entries. + bool changed_; // Presence of changed or missing entries. + }; + +#endif // BUILD2_BOOTSTRAP + } +} + +#endif // LIBBUILD2_CC_COMPILEDB_HXX |