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-rw-r--r--gnu/packages/patches/gcc-12-strmov-store-file-names.patch114
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