115 lines
4.0 KiB
Diff
115 lines
4.0 KiB
Diff
commit f7765f70e0e254fd9ce4469c7281c69cd06c9467
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Author: law <law@138bc75d-0d04-0410-961f-82ee72b054a4>
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Date: Wed Jan 24 21:57:16 2018 +0000
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PR target/83994
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* i386.c (get_probe_interval): Move to earlier point.
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(ix86_compute_frame_layout): If -fstack-clash-protection and
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the frame is larger than the probe interval, then use pushes
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to save registers rather than reg->mem moves.
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(ix86_expand_prologue): Remove conditional for int_registers_saved
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assertion.
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PR target/83994
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* gcc.target/i386/pr83994.c: New test.
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diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
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index 15cfe83..5230227 100644
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--- a/gcc/config/i386/i386.c
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+++ b/gcc/config/i386/i386.c
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@@ -9371,6 +9371,18 @@ ix86_builtin_setjmp_frame_value (void)
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return stack_realign_fp ? hard_frame_pointer_rtx : virtual_stack_vars_rtx;
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}
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+/* Return the probing interval for -fstack-clash-protection. */
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+
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+static HOST_WIDE_INT
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+get_probe_interval (void)
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+{
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+ if (flag_stack_clash_protection)
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+ return (HOST_WIDE_INT_1U
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+ << PARAM_VALUE (PARAM_STACK_CLASH_PROTECTION_PROBE_INTERVAL));
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+ else
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+ return (HOST_WIDE_INT_1U << STACK_CHECK_PROBE_INTERVAL_EXP);
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+}
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+
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/* When using -fsplit-stack, the allocation routines set a field in
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the TCB to the bottom of the stack plus this much space, measured
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in bytes. */
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@@ -9545,7 +9557,15 @@ ix86_compute_frame_layout (struct ix86_frame *frame)
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to_allocate = offset - frame->sse_reg_save_offset;
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if ((!to_allocate && frame->nregs <= 1)
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- || (TARGET_64BIT && to_allocate >= (HOST_WIDE_INT) 0x80000000))
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+ || (TARGET_64BIT && to_allocate >= (HOST_WIDE_INT) 0x80000000)
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+ /* If stack clash probing needs a loop, then it needs a
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+ scratch register. But the returned register is only guaranteed
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+ to be safe to use after register saves are complete. So if
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+ stack clash protections are enabled and the allocated frame is
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+ larger than the probe interval, then use pushes to save
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+ callee saved registers. */
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+ || (flag_stack_clash_protection && to_allocate > get_probe_interval ()))
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+
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frame->save_regs_using_mov = false;
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if (ix86_using_red_zone ()
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@@ -10181,18 +10201,6 @@ release_scratch_register_on_entry (struct scratch_reg *sr)
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}
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}
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-/* Return the probing interval for -fstack-clash-protection. */
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-
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-static HOST_WIDE_INT
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-get_probe_interval (void)
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-{
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- if (flag_stack_clash_protection)
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- return (HOST_WIDE_INT_1U
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- << PARAM_VALUE (PARAM_STACK_CLASH_PROTECTION_PROBE_INTERVAL));
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- else
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- return (HOST_WIDE_INT_1U << STACK_CHECK_PROBE_INTERVAL_EXP);
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-}
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-
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/* Emit code to adjust the stack pointer by SIZE bytes while probing it.
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This differs from the next routine in that it tries hard to prevent
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@@ -11064,12 +11072,11 @@ ix86_expand_prologue (void)
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&& (flag_stack_check == STATIC_BUILTIN_STACK_CHECK
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|| flag_stack_clash_protection))
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{
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- /* This assert wants to verify that integer registers were saved
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- prior to probing. This is necessary when probing may be implemented
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- as a function call (Windows). It is not necessary for stack clash
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- protection probing. */
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- if (!flag_stack_clash_protection)
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- gcc_assert (int_registers_saved);
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+ /* We expect the GP registers to be saved when probes are used
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+ as the probing sequences might need a scratch register and
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+ the routine to allocate one assumes the integer registers
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+ have already been saved. */
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+ gcc_assert (int_registers_saved);
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if (flag_stack_clash_protection)
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{
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diff --git a/gcc/testsuite/gcc.target/i386/pr83994.c b/gcc/testsuite/gcc.target/i386/pr83994.c
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new file mode 100644
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index 0000000..dc0b7cb
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--- /dev/null
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+++ b/gcc/testsuite/gcc.target/i386/pr83994.c
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@@ -0,0 +1,16 @@
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+/* { dg-do compile } */
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+/* { dg-options "-O2 -march=i686 -fpic -fstack-clash-protection" } */
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+/* { dg-require-effective-target ia32 } */
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+
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+void f1 (char *);
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+
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+__attribute__ ((regparm (3)))
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+int
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+f2 (int arg1, int arg2, int arg3)
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+{
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+ char buf[16384];
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+ f1 (buf);
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+ f1 (buf);
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+ return 0;
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+}
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+
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