From 9a775e9df5f72a8a9627fca8d412361562c8186a Mon Sep 17 00:00:00 2001 From: Max Filippov Date: Tue, 19 Jun 2018 18:26:07 +0000 Subject: [PATCH] xtensa: fix PR target/65416 The issue is caused by reordering of stack pointer update after stack space allocation with instructions that write to the allocated stack space. In windowed ABI register spill area for the previous call frame is located just below the stack pointer and may be reloaded back into the register file on movsp. Implement allocate_stack pattern for windowed ABI configuration and insert an instruction that prevents reordering of frame memory access and stack pointer update. gcc/ 2018-06-19 Max Filippov * config/xtensa/xtensa.md (UNSPEC_FRAME_BLOCKAGE): New unspec constant. (allocate_stack, frame_blockage, *frame_blockage): New patterns. From-SVN: r261755 --- gcc/ChangeLog | 6 +++++ gcc/config/xtensa/xtensa.md | 46 +++++++++++++++++++++++++++++++++++++ 2 files changed, 52 insertions(+) diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 4d59d2d1ee0..7e93801049c 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,9 @@ +2018-06-19 Max Filippov + + * config/xtensa/xtensa.md (UNSPEC_FRAME_BLOCKAGE): New unspec + constant. + (allocate_stack, frame_blockage, *frame_blockage): New patterns. + 2018-06-19 Jan Hubicka * tree.c (find_decls_types_r): Remove all non-VAR_DECLs from diff --git a/gcc/config/xtensa/xtensa.md b/gcc/config/xtensa/xtensa.md index 84967dbedc0..209f839cfb0 100644 --- a/gcc/config/xtensa/xtensa.md +++ b/gcc/config/xtensa/xtensa.md @@ -38,6 +38,7 @@ (UNSPEC_MEMW 11) (UNSPEC_LSETUP_START 12) (UNSPEC_LSETUP_END 13) + (UNSPEC_FRAME_BLOCKAGE 14) (UNSPECV_SET_FP 1) (UNSPECV_ENTRY 2) @@ -1676,6 +1677,32 @@ ;; Miscellaneous instructions. +;; In windowed ABI stack pointer adjustment must happen before any access +;; to the space allocated on stack is allowed, otherwise register spill +;; area may be clobbered. That's what frame blockage is supposed to enforce. + +(define_expand "allocate_stack" + [(set (match_operand 0 "nonimmed_operand") + (minus (reg A1_REG) (match_operand 1 "add_operand"))) + (set (reg A1_REG) + (minus (reg A1_REG) (match_dup 1)))] + "TARGET_WINDOWED_ABI" +{ + if (CONST_INT_P (operands[1])) + { + rtx neg_op0 = GEN_INT (-INTVAL (operands[1])); + emit_insn (gen_addsi3 (stack_pointer_rtx, stack_pointer_rtx, neg_op0)); + } + else + { + emit_insn (gen_subsi3 (stack_pointer_rtx, stack_pointer_rtx, + operands[1])); + } + emit_move_insn (operands[0], virtual_stack_dynamic_rtx); + emit_insn (gen_frame_blockage ()); + DONE; +}) + (define_expand "prologue" [(const_int 0)] "" @@ -1767,6 +1794,25 @@ [(set_attr "length" "0") (set_attr "type" "nop")]) +;; Do not schedule instructions accessing memory before this point. + +(define_expand "frame_blockage" + [(set (match_dup 0) + (unspec:BLK [(match_dup 1)] UNSPEC_FRAME_BLOCKAGE))] + "" +{ + operands[0] = gen_rtx_MEM (BLKmode, gen_rtx_SCRATCH (Pmode)); + MEM_VOLATILE_P (operands[0]) = 1; + operands[1] = stack_pointer_rtx; +}) + +(define_insn "*frame_blockage" + [(set (match_operand:BLK 0 "" "") + (unspec:BLK [(match_operand:SI 1 "" "")] UNSPEC_FRAME_BLOCKAGE))] + "" + "" + [(set_attr "length" "0")]) + (define_insn "trap" [(trap_if (const_int 1) (const_int 0))] "" -- 2.30.2