From 2e1eeae22bcbec6e17275417d7b8bc97300b7cb0 Mon Sep 17 00:00:00 2001 From: Andrew Stubbs Date: Fri, 8 Jan 2021 13:56:52 +0000 Subject: [PATCH] amdgcn: Fix DWARF variables with alloca Require a frame pointer for entry functions that use alloca because it isn't possible to encode the DWARF frame otherwise. Adjust the CFA definition expressions accordingly. gcc/ChangeLog: * config/gcn/gcn.c (gcn_expand_prologue): Use the frame pointer for the DWARF CFA, if it exists. (gcn_frame_pointer_rqd): Require a frame pointer for entry functions that use alloca. --- gcc/config/gcn/gcn.c | 21 +++++++++++++++++---- 1 file changed, 17 insertions(+), 4 deletions(-) diff --git a/gcc/config/gcn/gcn.c b/gcc/config/gcn/gcn.c index c1823e8747e0..784bae434198 100644 --- a/gcc/config/gcn/gcn.c +++ b/gcc/config/gcn/gcn.c @@ -3033,6 +3033,16 @@ gcn_expand_prologue () gen_rtx_SET (sp, gen_rtx_PLUS (DImode, sp, dbg_adjustment))); + if (offsets->need_frame_pointer) + { + /* Set the CFA to the entry stack address, as an offset from the + frame pointer. This is necessary when alloca is used, and + harmless otherwise. */ + rtx neg_adjust = gen_int_mode (-offsets->callee_saves, DImode); + add_reg_note (insn, REG_CFA_DEF_CFA, + gen_rtx_PLUS (DImode, fp, neg_adjust)); + } + /* Make sure the flat scratch reg doesn't get optimised away. */ emit_insn (gen_prologue_use (gen_rtx_REG (DImode, FLAT_SCRATCH_REG))); } @@ -3144,10 +3154,13 @@ bool gcn_frame_pointer_rqd (void) { /* GDB needs the frame pointer in order to unwind properly, - but that's not important for the entry point. - We should also repect the -fomit-frame-pointer flag. */ - return (cfun && cfun->machine && cfun->machine->normal_function - && !flag_omit_frame_pointer); + but that's not important for the entry point, unless alloca is used. + It's not important for code execution, so we should repect the + -fomit-frame-pointer flag. */ + return (!flag_omit_frame_pointer + && cfun + && (cfun->calls_alloca + || (cfun->machine && cfun->machine->normal_function))); } /* Implement TARGET_CAN_ELIMINATE. -- 2.47.3