115 lines
3.5 KiB
Diff
115 lines
3.5 KiB
Diff
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
|