202e5ccf04
-fstack-clash-protection. [bnc #1059075] Changes gcc43-stack-probe.diff . OBS-URL: https://build.opensuse.org/package/show/devel:gcc/gcc7?expand=0&rev=83
112 lines
3.8 KiB
Diff
112 lines
3.8 KiB
Diff
Index: gcc/common.opt
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===================================================================
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--- gcc/common.opt (revision 244266)
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+++ gcc/common.opt (working copy)
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@@ -2295,6 +2299,10 @@ fstack-check
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Common Alias(fstack-check=, specific, no)
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Insert stack checking code into the program. Same as -fstack-check=specific.
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+fstack-clash-protection
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+Common Report Var(flag_stack_clash_protection)
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+Insert probes per page for dynamically allocated stack space
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+
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fstack-limit
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Common Var(common_deferred_options) Defer
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Index: gcc/explow.c
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===================================================================
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--- gcc/explow.c (revision 244266)
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+++ gcc/explow.c (working copy)
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@@ -1277,6 +1277,8 @@ get_dynamic_stack_size (rtx *psize, unsi
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*psize = size;
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}
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+#define PROBE_INTERVAL (1 << STACK_CHECK_PROBE_INTERVAL_EXP)
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+
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/* Return an rtx representing the address of an area of memory dynamically
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pushed on the stack.
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@@ -1305,6 +1307,8 @@ allocate_dynamic_stack_space (rtx size,
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HOST_WIDE_INT stack_usage_size = -1;
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rtx_code_label *final_label;
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rtx final_target, target;
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+ rtx loop_lab, end_lab, skip_lab, last_size, before_skip;
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+ int probe_pass = 0;
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/* If we're asking for zero bytes, it doesn't matter what we point
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to since we can't dereference it. But return a reasonable
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@@ -1440,6 +1444,30 @@ allocate_dynamic_stack_space (rtx size,
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/* Don't let anti_adjust_stack emit notes. */
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suppress_reg_args_size = true;
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+ if (flag_stack_clash_protection)
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+ {
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+#ifndef STACK_GROWS_DOWNWARD
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+ sorry("-fstack-clash-protection is incompatible with upward growing stack");
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+#endif
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+ size = copy_to_mode_reg (Pmode, convert_to_mode (Pmode, size, 1));
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+ loop_lab = gen_label_rtx ();
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+ end_lab = gen_label_rtx ();
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+ skip_lab = gen_label_rtx ();
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+ /* We insert 'target = virtual_stack_dynamic_rtx' here, but target
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+ is changed later, so that insn can be constructed only later. */
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+ before_skip = get_last_insn ();
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+ emit_cmp_and_jump_insns (size, CONST0_RTX (Pmode), EQ, NULL_RTX,
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+ Pmode, 1, skip_lab);
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+ emit_label (loop_lab);
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+ emit_cmp_and_jump_insns (size, GEN_INT (PROBE_INTERVAL), LTU,
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+ NULL_RTX, Pmode, 1, end_lab);
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+ last_size = expand_binop (Pmode, sub_optab, size, GEN_INT (PROBE_INTERVAL), size,
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+ 1, OPTAB_WIDEN);
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+ gcc_assert (last_size == size);
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+ size = GEN_INT (PROBE_INTERVAL);
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+ }
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+
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+again:
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/* Perform the required allocation from the stack. Some systems do
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this differently than simply incrementing/decrementing from the
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stack pointer, such as acquiring the space by calling malloc(). */
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@@ -1499,6 +1527,15 @@ allocate_dynamic_stack_space (rtx size,
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if (STACK_GROWS_DOWNWARD)
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emit_move_insn (target, virtual_stack_dynamic_rtx);
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}
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+ if (flag_stack_clash_protection && probe_pass == 0)
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+ {
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+ probe_pass = 1;
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+ emit_stack_probe (target);
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+ emit_jump (loop_lab);
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+ emit_label (end_lab);
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+ size = last_size;
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+ goto again;
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+ }
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suppress_reg_args_size = false;
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@@ -1510,6 +1547,17 @@ allocate_dynamic_stack_space (rtx size,
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emit_label (final_label);
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target = final_target;
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}
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+ if (flag_stack_clash_protection)
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+ {
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+ rtx seq;
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+ emit_stack_probe (target);
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+ emit_label (skip_lab);
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+ start_sequence ();
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+ emit_move_insn (target, virtual_stack_dynamic_rtx);
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+ seq = get_insns ();
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+ end_sequence ();
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+ emit_insn_after (seq, before_skip);
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+ }
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target = align_dynamic_address (target, required_align);
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@@ -1593,8 +1641,6 @@ emit_stack_probe (rtx address)
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the current stack pointer. STACK_GROWS_DOWNWARD says whether to add
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or subtract them from the stack pointer. */
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-#define PROBE_INTERVAL (1 << STACK_CHECK_PROBE_INTERVAL_EXP)
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-
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#if STACK_GROWS_DOWNWARD
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#define STACK_GROW_OP MINUS
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#define STACK_GROW_OPTAB sub_optab
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