mirror of
https://git.in.rschanz.org/ryan77627/guix.git
synced 2024-12-30 16:12:58 -05:00
243ea8673f
Fixes <https://bugs.gnu.org/31708>. Previously GCC would crash when encountering a 'static const' element without an initializer, as in: #define _GNU_SOURCE #include <string.h> void foo (char *x) { static const char buf[12]; memcpy (x, buf, 12); } * gnu/packages/patches/gcc-strmov-store-file-names.patch: Return false when DECL_INITIAL returns NULL_TREE.
112 lines
3.2 KiB
Diff
112 lines
3.2 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>.
|
|
|
|
|
|
--- gcc-5.3.0/gcc/builtins.c 2016-10-18 10:50:46.080616285 +0200
|
|
+++ gcc-5.3.0/gcc/builtins.c 2016-11-09 15:26:43.693042737 +0100
|
|
@@ -3192,6 +3192,58 @@ determine_block_size (tree len, rtx len_
|
|
GET_MODE_MASK (GET_MODE (len_rtx)));
|
|
}
|
|
|
|
+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_builtin_memcpy. */
|
|
|
|
static rtx
|
|
@@ -3207,6 +3243,13 @@ expand_builtin_memcpy_args (tree dest, t
|
|
unsigned HOST_WIDE_INT max_size;
|
|
unsigned HOST_WIDE_INT probable_max_size;
|
|
|
|
+ /* 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;
|
|
|
|
--- gcc-5.5.0/gcc/gimple-fold.c 2018-03-20 11:36:16.709442004 +0100
|
|
+++ gcc-5.5.0/gcc/gimple-fold.c 2018-03-20 11:46:43.838487065 +0100
|
|
@@ -769,6 +769,8 @@ var_decl_component_p (tree var)
|
|
return SSA_VAR_P (inner);
|
|
}
|
|
|
|
+extern bool store_reference_p (tree);
|
|
+
|
|
/* Fold function call to builtin mem{{,p}cpy,move}. Return
|
|
false if no simplification can be made.
|
|
If ENDP is 0, return DEST (like memcpy).
|
|
@@ -1099,6 +1101,9 @@ gimple_fold_builtin_memory_op (gimple_st
|
|
if (!srctype)
|
|
return false;
|
|
|
|
+ if (store_reference_p (src))
|
|
+ return false;
|
|
+
|
|
src_align = get_pointer_alignment (src);
|
|
dest_align = get_pointer_alignment (dest);
|
|
if (dest_align < TYPE_ALIGN (desttype)
|