Commit | Line | Data |
---|---|---|
80337723 LC |
1 | Make sure that statements such as: |
2 | ||
3 | strcpy (dst, "/gnu/store/…"); | |
4 | ||
e2885727 LC |
5 | or |
6 | ||
7 | static const char str[] = "/gnu/store/…"; | |
8 | … | |
9 | strcpy (dst, str); | |
10 | ||
80337723 | 11 | do not result in chunked /gnu/store strings that are undetectable by |
e2885727 LC |
12 | Guix's GC and its grafting code. See <https://bugs.gnu.org/24703> |
13 | and <https://bugs.gnu.org/30395>. | |
14 | ||
80337723 LC |
15 | |
16 | --- gcc-5.3.0/gcc/builtins.c 2016-10-18 10:50:46.080616285 +0200 | |
17 | +++ gcc-5.3.0/gcc/builtins.c 2016-11-09 15:26:43.693042737 +0100 | |
243ea867 | 18 | @@ -3192,6 +3192,58 @@ determine_block_size (tree len, rtx len_ |
80337723 LC |
19 | GET_MODE_MASK (GET_MODE (len_rtx))); |
20 | } | |
21 | ||
e2885727 LC |
22 | +extern void debug_tree (tree); |
23 | + | |
80337723 LC |
24 | +/* Return true if STR contains the string "/gnu/store". */ |
25 | + | |
e2885727 | 26 | +bool |
80337723 LC |
27 | +store_reference_p (tree str) |
28 | +{ | |
e2885727 LC |
29 | + if (getenv ("GUIX_GCC_DEBUG") != NULL) |
30 | + debug_tree (str); | |
31 | + | |
80337723 LC |
32 | + if (TREE_CODE (str) == ADDR_EXPR) |
33 | + str = TREE_OPERAND (str, 0); | |
34 | + | |
e2885727 LC |
35 | + if (TREE_CODE (str) == VAR_DECL |
36 | + && TREE_STATIC (str) | |
37 | + && TREE_READONLY (str)) | |
243ea867 LC |
38 | + { |
39 | + /* STR may be a 'static const' variable whose initial value | |
40 | + is a string constant. See <https://bugs.gnu.org/30395>. */ | |
41 | + str = DECL_INITIAL (str); | |
42 | + if (str == NULL_TREE) | |
43 | + return false; | |
44 | + } | |
e2885727 | 45 | + |
80337723 LC |
46 | + if (TREE_CODE (str) != STRING_CST) |
47 | + return false; | |
48 | + | |
49 | + int len; | |
50 | + const char *store; | |
51 | + | |
52 | + store = getenv ("NIX_STORE") ? getenv ("NIX_STORE") : "/gnu/store"; | |
53 | + len = strlen (store); | |
54 | + | |
55 | + /* Size of the hash part of store file names, including leading slash and | |
56 | + trailing hyphen. */ | |
57 | + const int hash_len = 34; | |
58 | + | |
59 | + if (TREE_STRING_LENGTH (str) < len + hash_len) | |
60 | + return false; | |
61 | + | |
62 | + /* We cannot use 'strstr' because 'TREE_STRING_POINTER' returns a string | |
63 | + that is not necessarily NUL-terminated. */ | |
64 | + | |
65 | + for (int i = 0; i < TREE_STRING_LENGTH (str) - (len + hash_len); i++) | |
66 | + { | |
67 | + if (strncmp (TREE_STRING_POINTER (str) + i, store, len) == 0) | |
68 | + return true; | |
69 | + } | |
70 | + | |
71 | + return false; | |
72 | +} | |
73 | + | |
74 | /* Helper function to do the actual work for expand_builtin_memcpy. */ | |
75 | ||
76 | static rtx | |
77 | @@ -3207,6 +3243,13 @@ expand_builtin_memcpy_args (tree dest, t | |
78 | unsigned HOST_WIDE_INT max_size; | |
79 | unsigned HOST_WIDE_INT probable_max_size; | |
80 | ||
81 | + /* Do not emit block moves, which translate to the 'movabs' instruction on | |
82 | + x86_64, when SRC refers to store items. That way, store references | |
83 | + remain visible to the Guix GC and grafting code. See | |
e2885727 | 84 | + <https://bugs.gnu.org/24703>. */ |
80337723 LC |
85 | + if (store_reference_p (src)) |
86 | + return NULL_RTX; | |
87 | + | |
88 | /* If DEST is not a pointer type, call the normal function. */ | |
89 | if (dest_align == 0) | |
90 | return NULL_RTX; | |
e2885727 LC |
91 | |
92 | --- gcc-5.5.0/gcc/gimple-fold.c 2018-03-20 11:36:16.709442004 +0100 | |
93 | +++ gcc-5.5.0/gcc/gimple-fold.c 2018-03-20 11:46:43.838487065 +0100 | |
94 | @@ -769,6 +769,8 @@ var_decl_component_p (tree var) | |
95 | return SSA_VAR_P (inner); | |
96 | } | |
97 | ||
98 | +extern bool store_reference_p (tree); | |
99 | + | |
100 | /* Fold function call to builtin mem{{,p}cpy,move}. Return | |
101 | false if no simplification can be made. | |
102 | If ENDP is 0, return DEST (like memcpy). | |
103 | @@ -1099,6 +1101,9 @@ gimple_fold_builtin_memory_op (gimple_st | |
104 | if (!srctype) | |
105 | return false; | |
106 | ||
107 | + if (store_reference_p (src)) | |
108 | + return false; | |
109 | + | |
110 | src_align = get_pointer_alignment (src); | |
111 | dest_align = get_pointer_alignment (dest); | |
112 | if (dest_align < TYPE_ALIGN (desttype) |