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gnu: gcc: Adjust 'strmov' patch for string constants in variables.

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Fixes <https://bugs.gnu.org/30395>.

* gnu/packages/patches/gcc-strmov-store-file-names.patch: Update patch
to deal with string constants stored in 'static' variables.
This commit is contained in:
Ludovic Courtès 2018-03-20 23:36:55 +01:00
parent ac21be848a
commit e288572710
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GPG key ID: 090B11993D9AEBB5
1 changed files with 46 additions and 4 deletions
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50
gnu/packages/patches/gcc-strmov-store-file-names.patch
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@ -2,23 +2,43 @@ 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 <http://bugs.gnu.org/24703>.
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 +3192,42 @@ determine_block_size (tree len, rtx len_
@@ -3192,6 +3192,54 @@ 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". */
+
+static bool
+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 (TREE_CODE (str) != STRING_CST)
+ return false;
+
@ -57,10 +77,32 @@ Guix's GC and its grafting code. See <http://bugs.gnu.org/24703>.
+ /* 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
+ <http://bugs.gnu.org/24703>. */
+ <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)