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92 lines
3.0 KiB
92 lines
3.0 KiB
5 months ago
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commit ef5f7b89bbc352255595069eb870d6f30f1f9134
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Author: Andreas Krebbel <krebbel@linux.ibm.com>
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Date: Wed Feb 1 08:59:41 2023 +0100
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New reg note REG_CFA_NORESTORE
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This patch introduces a new reg note which can be used to tell the CFI
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verification in dwarf2cfi that a register is stored without intending
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to restore from it.
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This is useful when storing e.g. register contents to the stack and
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generate CFI for it although the register is not really supposed to be
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restored.
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gcc/ChangeLog:
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* dwarf2cfi.c (dwarf2out_frame_debug_cfa_restore): Add
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EMIT_CFI parameter.
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(dwarf2out_frame_debug): Add case for REG_CFA_NORESTORE.
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* reg-notes.def (REG_CFA_NOTE): New reg note definition.
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--- a/gcc/dwarf2cfi.c
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+++ b/gcc/dwarf2cfi.c
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@@ -1496,10 +1496,12 @@ dwarf2out_frame_debug_cfa_val_expression (rtx set)
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update_row_reg_save (cur_row, dwf_regno (dest), cfi);
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}
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-/* A subroutine of dwarf2out_frame_debug, process a REG_CFA_RESTORE note. */
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+/* A subroutine of dwarf2out_frame_debug, process a REG_CFA_RESTORE
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+ note. When called with EMIT_CFI set to false emitting a CFI
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+ statement is suppressed. */
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static void
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-dwarf2out_frame_debug_cfa_restore (rtx reg)
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+dwarf2out_frame_debug_cfa_restore (rtx reg, bool emit_cfi)
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{
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gcc_assert (REG_P (reg));
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@@ -1507,7 +1509,8 @@ dwarf2out_frame_debug_cfa_restore (rtx reg)
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if (!span)
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{
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unsigned int regno = dwf_regno (reg);
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- add_cfi_restore (regno);
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+ if (emit_cfi)
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+ add_cfi_restore (regno);
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update_row_reg_save (cur_row, regno, NULL);
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}
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else
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@@ -1522,7 +1525,8 @@ dwarf2out_frame_debug_cfa_restore (rtx reg)
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reg = XVECEXP (span, 0, par_index);
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gcc_assert (REG_P (reg));
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unsigned int regno = dwf_regno (reg);
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- add_cfi_restore (regno);
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+ if (emit_cfi)
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+ add_cfi_restore (regno);
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update_row_reg_save (cur_row, regno, NULL);
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}
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}
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@@ -2309,6 +2313,7 @@ dwarf2out_frame_debug (rtx_insn *insn)
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break;
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case REG_CFA_RESTORE:
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+ case REG_CFA_NO_RESTORE:
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n = XEXP (note, 0);
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if (n == NULL)
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{
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@@ -2317,7 +2322,7 @@ dwarf2out_frame_debug (rtx_insn *insn)
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n = XVECEXP (n, 0, 0);
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n = XEXP (n, 0);
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}
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- dwarf2out_frame_debug_cfa_restore (n);
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+ dwarf2out_frame_debug_cfa_restore (n, REG_NOTE_KIND (note) == REG_CFA_RESTORE);
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handled_one = true;
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break;
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diff --git a/gcc/reg-notes.def b/gcc/reg-notes.def
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index 23de1f13ee9..1f74a605b3e 100644
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--- a/gcc/reg-notes.def
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+++ b/gcc/reg-notes.def
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@@ -157,6 +157,11 @@ REG_CFA_NOTE (CFA_VAL_EXPRESSION)
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first pattern is the register to be restored. */
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REG_CFA_NOTE (CFA_RESTORE)
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+/* Like CFA_RESTORE but without actually emitting CFI. This can be
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+ used to tell the verification infrastructure that a register is
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+ saved without intending to restore it. */
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+REG_CFA_NOTE (CFA_NO_RESTORE)
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+
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/* Attached to insns that are RTX_FRAME_RELATED_P, marks insn that sets
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vDRAP from DRAP. If vDRAP is a register, vdrap_reg is initalized
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to the argument, if it is a MEM, it is ignored. */
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