diff options
Diffstat (limited to 'gnu/packages/patches/gcc-12-strmov-store-file-names.patch')
| -rw-r--r-- | gnu/packages/patches/gcc-12-strmov-store-file-names.patch | 114 |
1 files changed, 114 insertions, 0 deletions
diff --git a/gnu/packages/patches/gcc-12-strmov-store-file-names.patch b/gnu/packages/patches/gcc-12-strmov-store-file-names.patch new file mode 100644 index 0000000000..091fc3f576 --- /dev/null +++ b/gnu/packages/patches/gcc-12-strmov-store-file-names.patch @@ -0,0 +1,114 @@ +Make sure that statements such as: + + strcpy (dst, "/gnu/store/…"); + +or + + static const char str[] = "/gnu/store/…"; + … + strcpy (dst, str); + +do not result in chunked /gnu/store strings that are undetectable by +Guix's GC and its grafting code. See <https://bugs.gnu.org/24703> +and <https://bugs.gnu.org/30395>. + +diff --git a/gcc/builtins.cc b/gcc/builtins.cc +index 5b085e3a1..480bc0b54 100644 +--- a/gcc/builtins.cc ++++ b/gcc/builtins.cc +@@ -3363,6 +3363,58 @@ expand_builtin_mempcpy (tree exp, rtx target) + target, exp, /*retmode=*/ RETURN_END); + } + ++extern void debug_tree (tree); ++ ++/* Return true if STR contains the string "/gnu/store". */ ++ ++bool ++store_reference_p (tree str) ++{ ++ if (getenv ("GUIX_GCC_DEBUG") != NULL) ++ debug_tree (str); ++ ++ if (TREE_CODE (str) == ADDR_EXPR) ++ str = TREE_OPERAND (str, 0); ++ ++ if (TREE_CODE (str) == VAR_DECL ++ && TREE_STATIC (str) ++ && TREE_READONLY (str)) ++ { ++ /* STR may be a 'static const' variable whose initial value ++ is a string constant. See <https://bugs.gnu.org/30395>. */ ++ str = DECL_INITIAL (str); ++ if (str == NULL_TREE) ++ return false; ++ } ++ ++ if (TREE_CODE (str) != STRING_CST) ++ return false; ++ ++ int len; ++ const char *store; ++ ++ store = getenv ("NIX_STORE") ? getenv ("NIX_STORE") : "/gnu/store"; ++ len = strlen (store); ++ ++ /* Size of the hash part of store file names, including leading slash and ++ trailing hyphen. */ ++ const int hash_len = 34; ++ ++ if (TREE_STRING_LENGTH (str) < len + hash_len) ++ return false; ++ ++ /* We cannot use 'strstr' because 'TREE_STRING_POINTER' returns a string ++ that is not necessarily NUL-terminated. */ ++ ++ for (int i = 0; i < TREE_STRING_LENGTH (str) - (len + hash_len); i++) ++ { ++ if (strncmp (TREE_STRING_POINTER (str) + i, store, len) == 0) ++ return true; ++ } ++ ++ return false; ++} ++ + /* Helper function to do the actual work for expand of memory copy family + functions (memcpy, mempcpy, stpcpy). Expansing should assign LEN bytes + of memory from SRC to DEST and assign to TARGET if convenient. Return +@@ -3384,6 +3436,13 @@ expand_builtin_memory_copy_args (tree dest, tree src, tree len, + + bool is_move_done; + ++ /* Do not emit block moves, which translate to the 'movabs' instruction on ++ x86_64, when SRC refers to store items. That way, store references ++ remain visible to the Guix GC and grafting code. See ++ <https://bugs.gnu.org/24703>. */ ++ if (store_reference_p (src)) ++ return NULL_RTX; ++ + /* If DEST is not a pointer type, call the normal function. */ + if (dest_align == 0) + return NULL_RTX; +diff --git a/gcc/gimple-fold.cc b/gcc/gimple-fold.cc +index 863ee3d39..4cc46c265 100644 +--- a/gcc/gimple-fold.cc ++++ b/gcc/gimple-fold.cc +@@ -856,6 +856,8 @@ var_decl_component_p (tree var) + && TREE_CODE (TREE_OPERAND (inner, 0)) == ADDR_EXPR)); + } + ++extern bool store_reference_p (tree); ++ + /* Return TRUE if the SIZE argument, representing the size of an + object, is in a range of values of which exactly zero is valid. */ + +@@ -960,6 +962,9 @@ gimple_fold_builtin_memory_op (gimple_stmt_iterator *gsi, + = build_int_cst (build_pointer_type_for_mode (char_type_node, + ptr_mode, true), 0); + ++ if (store_reference_p (src)) ++ return false; ++ + /* If we can perform the copy efficiently with first doing all loads + and then all stores inline it that way. Currently efficiently + means that we can load all the memory into a single integer |