From 8aee78c8d0eb06334571e596f6fbdf7ed5756f0c Mon Sep 17 00:00:00 2001 From: Boris Kolpackov Date: Wed, 8 Feb 2017 09:24:07 +0200 Subject: Tighten target constness further --- build2/bin/target | 14 +++++++++----- build2/cc/utility.cxx | 4 +--- build2/cli/rule.cxx | 2 +- build2/cli/target | 39 ++++++++++++--------------------------- build2/cli/target.cxx | 9 +++++++-- build2/target | 18 ++++++++---------- build2/target.cxx | 2 +- 7 files changed, 39 insertions(+), 49 deletions(-) (limited to 'build2') diff --git a/build2/bin/target b/build2/bin/target index 85a84df..0108f09 100644 --- a/build2/bin/target +++ b/build2/bin/target @@ -51,9 +51,11 @@ namespace build2 public: using target::target; - obje* e {nullptr}; - obja* a {nullptr}; - objs* s {nullptr}; + // Group members. + // + const_ptr e = nullptr; + const_ptr a = nullptr; + const_ptr s = nullptr; public: static const target_type static_type; @@ -87,8 +89,10 @@ namespace build2 public: using target::target; - liba* a {nullptr}; - libs* s {nullptr}; + // Group members. + // + const_ptr a = nullptr; + const_ptr s = nullptr; virtual void reset (action_type) override; diff --git a/build2/cc/utility.cxx b/build2/cc/utility.cxx index 4ccdcaf..62febfa 100644 --- a/build2/cc/utility.cxx +++ b/build2/cc/utility.cxx @@ -62,10 +62,8 @@ namespace build2 } } - target* r (ls ? static_cast (l.s) : l.a); - + const target* r (ls ? static_cast (l.s) : l.a); assert (r != nullptr); - return *r; } diff --git a/build2/cli/rule.cxx b/build2/cli/rule.cxx index 7928c5c..ba4963e 100644 --- a/build2/cli/rule.cxx +++ b/build2/cli/rule.cxx @@ -207,7 +207,7 @@ namespace build2 static void append_extension (cstrings& args, - path_target& t, + const path_target& t, const char* option, const char* default_extension) { diff --git a/build2/cli/target b/build2/cli/target index f4ab7e7..c10e4b8 100644 --- a/build2/cli/target +++ b/build2/cli/target @@ -26,37 +26,22 @@ namespace build2 virtual const target_type& dynamic_type () const {return static_type;} }; - class cli_cxx: public mtime_target + // Standard layout type compatible with target*[3]. + // + struct cli_cxx_members { - public: - union - { - // It is theoretically possible that the compiler will add - // padding between the members of this struct. This would - // mean that the optimal alignment for a pointer is greater - // than its size (and that an array of pointers is sub- - // optimally aligned). We will deal with such a beast of - // an architecture when we see it. - // - struct - { - cxx::hxx* h; - cxx::cxx* c; - cxx::ixx* i; - }; - target* m[3] /*= {nullptr, nullptr, nullptr}*/; // @@ GCC 4.8 - }; - - //using mtime_target::mtime_target; // @@ GCC 4.8 + const_ptr h = nullptr; + const_ptr c = nullptr; + const_ptr i = nullptr; + }; - cli_cxx (dir_path d, dir_path o, string n) - : mtime_target (move (d), move (o), move (n)) - { - m[0] = m[1] = m[2] = nullptr; - } + class cli_cxx: public mtime_target, public cli_cxx_members + { + public: + using mtime_target::mtime_target; virtual group_view - group_members (action_type) const; + group_members (action_type); virtual timestamp load_mtime () const; diff --git a/build2/cli/target.cxx b/build2/cli/target.cxx index 48dc95b..200f6f0 100644 --- a/build2/cli/target.cxx +++ b/build2/cli/target.cxx @@ -32,10 +32,15 @@ namespace build2 // cli.cxx // group_view cli_cxx:: - group_members (action_type) const + group_members (action_type) { + static_assert (offsetof (cli_cxx_members, i) - + offsetof (cli_cxx_members, h) == sizeof (target*) * 2, + "member layout incompatible with array"); + return h != nullptr - ? group_view {m, (i != nullptr ? 3U : 2U)} + ? group_view {reinterpret_cast (&h), + (i != nullptr ? 3U : 2U)} : group_view {nullptr, 0}; } diff --git a/build2/target b/build2/target index 90aaeec..6cc492a 100644 --- a/build2/target +++ b/build2/target @@ -250,7 +250,7 @@ namespace build2 // resolve_group_members() from . // virtual group_view - group_members (action_type) const; + group_members (action_type); // Note that the returned key "tracks" the target (except for the // extension). @@ -475,9 +475,11 @@ namespace build2 // // Currenly the data is not destroyed until the next match. // - static constexpr size_t data_size = sizeof (string) * 4; - std::aligned_storage::type data_pad; - void (*data_dtor) (void*) = nullptr; + // Note that the recipe may modify (mutable) the data. + // + static constexpr size_t data_size = sizeof (string) * 4; + mutable std::aligned_storage::type data_pad; + mutable void (*data_dtor) (void*) = nullptr; template T& - data () {return *reinterpret_cast (&data_pad);} - - template - const T& - data () const {return *reinterpret_cast (&data_pad);} + data () const {return *reinterpret_cast (&data_pad);} void - clear_data () + clear_data () const { if (data_dtor != nullptr) { diff --git a/build2/target.cxx b/build2/target.cxx index ad448cb..b22dfce 100644 --- a/build2/target.cxx +++ b/build2/target.cxx @@ -139,7 +139,7 @@ namespace build2 } group_view target:: - group_members (action_type) const + group_members (action_type) { assert (false); // Not a group or doesn't expose its members. return group_view {nullptr, 0}; -- cgit v1.1