diff options
Diffstat (limited to 'nixpkgs/pkgs/development/compilers/gcc/patches/13/mangle-NIX_STORE-in-__FILE__.patch')
| -rw-r--r-- | nixpkgs/pkgs/development/compilers/gcc/patches/13/mangle-NIX_STORE-in-__FILE__.patch | 84 |
1 files changed, 84 insertions, 0 deletions
diff --git a/nixpkgs/pkgs/development/compilers/gcc/patches/13/mangle-NIX_STORE-in-__FILE__.patch b/nixpkgs/pkgs/development/compilers/gcc/patches/13/mangle-NIX_STORE-in-__FILE__.patch new file mode 100644 index 000000000000..57ae2111f020 --- /dev/null +++ b/nixpkgs/pkgs/development/compilers/gcc/patches/13/mangle-NIX_STORE-in-__FILE__.patch @@ -0,0 +1,84 @@ +From b10785c1be469319a09b10bc69db21159b0599ee Mon Sep 17 00:00:00 2001 +From: Sergei Trofimovich <siarheit@google.com> +Date: Fri, 22 Sep 2023 22:41:49 +0100 +Subject: [PATCH] gcc/file-prefix-map.cc: always mangle __FILE__ into invalid + store path + +Without the change `__FILE__` used in static inline functions in headers +embed paths to header files into executable images. For local headers +it's not a problem, but for headers in `/nix/store` this causes `-dev` +inputs to be retained in runtime closure. + +Typical examples are `nix` -> `nlohmann_json` and `pipewire` -> +`lttng-ust.dev`. + +Ideally we would like to use `-fmacro-prefix-map=` feature of `gcc` as: + + -fmacro-prefix-map=/nix/store/$hash1-nlohmann-json-ver=/nix/store/eeee.eee-nlohmann-json-ver + -fmacro-prefix-map=/nix/... + +In practice it quickly exhausts argument lengtth limit due to `gcc` +deficiency: https://gcc.gnu.org/PR111527 + +Until it;s fixed let's hardcode header mangling if $NIX_STORE variable +is present in the environment. + +Tested as: + + $ printf "# 0 \"/nix/store/01234567890123456789012345678901-pppppp-vvvvvvv\" \nconst char * f(void) { return __FILE__; }" | NIX_STORE=/nix/store ./gcc/xgcc -Bgcc -x c - -S -o - + ... + .string "/nix/store/eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee-pppppp-vvvvvvv" + ... + +Mangled successfully. +--- a/gcc/file-prefix-map.cc ++++ b/gcc/file-prefix-map.cc +@@ -69,6 +69,9 @@ add_prefix_map (file_prefix_map *&maps, const char *arg, const char *opt) + maps = map; + } + ++/* Forward declaration for a $NIX_STORE remap hack below. */ ++static file_prefix_map *macro_prefix_maps; /* -fmacro-prefix-map */ ++ + /* Perform user-specified mapping of filename prefixes. Return the + GC-allocated new name corresponding to FILENAME or FILENAME if no + remapping was performed. */ +@@ -102,6 +105,29 @@ remap_filename (file_prefix_map *maps, const char *filename) + break; + if (!map) + { ++ if (maps == macro_prefix_maps) ++ { ++ /* Remap all fo $NIX_STORE/.{32} paths to ++ * equivalent $NIX_STORE/e{32}. ++ * ++ * That way we avoid argument parameters explosion ++ * and still avoid embedding headers into runtime closure: ++ * https://gcc.gnu.org/PR111527 ++ */ ++ char * nix_store = getenv("NIX_STORE"); ++ size_t nix_store_len = nix_store ? strlen(nix_store) : 0; ++ const char * name = realname ? realname : filename; ++ size_t name_len = strlen(name); ++ if (nix_store && name_len >= nix_store_len + 1 + 32 && memcmp(name, nix_store, nix_store_len) == 0) ++ { ++ s = (char *) ggc_alloc_atomic (name_len + 1); ++ memcpy(s, name, name_len + 1); ++ memset(s + nix_store_len + 1, 'e', 32); ++ if (realname != filename) ++ free (const_cast <char *> (realname)); ++ return s; ++ } ++ } + if (realname != filename) + free (const_cast <char *> (realname)); + return filename; +@@ -124,7 +150,6 @@ remap_filename (file_prefix_map *maps, const char *filename) + ignore it in DW_AT_producer (gen_command_line_string in opts.cc). */ + + /* Linked lists of file_prefix_map structures. */ +-static file_prefix_map *macro_prefix_maps; /* -fmacro-prefix-map */ + static file_prefix_map *debug_prefix_maps; /* -fdebug-prefix-map */ + static file_prefix_map *profile_prefix_maps; /* -fprofile-prefix-map */ + + |