From a42f1f7028fa80961114dab58ec9e028fcf9f9bd Mon Sep 17 00:00:00 2001
From: Richard Lowe <richlowe@richlowe.net>
Date: Fri, 3 May 2019 00:56:45 +0000
Subject: i386: don't assert the FP is valid during epilogue
adjustment
I did this, I think, to double check some assumptions. Unfortunately,
there is a case where the fp won't be valid here, despite us having
saved arguments. That where we're returning through an error handler
via __builtin_eh_return().
While here, make the code more readable and conventional.
---
gcc/config/i386/i386.cc | 68 +++++++++++++++++++----------------------
1 file changed, 32 insertions(+), 36 deletions(-)
diff --git a/gcc/config/i386/i386.cc b/gcc/config/i386/i386.cc
index 25ae3371a45f..6387a7206f63 100644
--- a/gcc/config/i386/i386.cc
+++ b/gcc/config/i386/i386.cc
@@ -7198,21 +7198,21 @@ static void
ix86_emit_save_regs (void)
{
unsigned int regno;
+ struct ix86_frame &frame = cfun->machine->frame;
rtx_insn *insn;
if (TARGET_SAVE_ARGS)
{
int i;
- int nsaved = ix86_nsaved_args ();
int start = cfun->returns_struct;
- for (i = start; i < start + nsaved; i++)
+ for (i = start; i < start + frame.nmsave_args; i++)
{
regno = x86_64_int_parameter_registers[i];
insn = emit_insn (gen_push (gen_rtx_REG (word_mode, regno)));
RTX_FRAME_RELATED_P (insn) = 1;
}
- if (nsaved % 2 != 0)
+ if (frame.nmsave_args % 2 != 0)
pro_epilogue_adjust_stack (stack_pointer_rtx, stack_pointer_rtx,
GEN_INT (-UNITS_PER_WORD), -1, false);
}
@@ -7303,22 +7303,21 @@ ix86_emit_save_reg_using_mov (machine_mode mode, unsigned int regno,
/* Emit code to save registers using MOV insns.
First register is stored at CFA - CFA_OFFSET. */
static void
-ix86_emit_save_regs_using_mov (const struct ix86_frame *frame)
+ix86_emit_save_regs_using_mov (const struct ix86_frame &frame)
{
unsigned int regno;
- HOST_WIDE_INT cfa_offset = frame->arg_save_offset;
+ HOST_WIDE_INT cfa_offset = frame.arg_save_offset;
if (TARGET_SAVE_ARGS)
{
int i;
- int nsaved = ix86_nsaved_args ();
int start = cfun->returns_struct;
/* We deal with this twice? */
- if (nsaved % 2 != 0)
+ if (frame.nmsave_args % 2 != 0)
cfa_offset -= UNITS_PER_WORD;
- for (i = start + nsaved - 1; i >= start; i--)
+ for (i = start + frame.nmsave_args - 1; i >= start; i--)
{
regno = x86_64_int_parameter_registers[i];
ix86_emit_save_reg_using_mov(word_mode, regno, cfa_offset);
@@ -7326,7 +7325,7 @@ ix86_emit_save_regs_using_mov (const struct ix86_frame *frame)
}
}
- cfa_offset = frame->reg_save_offset;
+ cfa_offset = frame.reg_save_offset;
for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++)
if (GENERAL_REGNO_P (regno) && ix86_save_reg (regno, true, true))
@@ -8723,7 +8722,7 @@ ix86_expand_prologue (void)
&& (! TARGET_STACK_PROBE
|| frame.stack_pointer_offset < CHECK_STACK_LIMIT))
{
- ix86_emit_save_regs_using_mov (&frame);
+ ix86_emit_save_regs_using_mov (frame);
cfun->machine->red_zone_used = true;
int_registers_saved = true;
}
@@ -9023,7 +9022,7 @@ ix86_expand_prologue (void)
}
if (!int_registers_saved)
- ix86_emit_save_regs_using_mov (&frame);
+ ix86_emit_save_regs_using_mov (frame);
if (!sse_registers_saved)
ix86_emit_save_sse_regs_using_mov (frame.sse_reg_save_offset);
else if (save_stub_call_needed)
@@ -9683,33 +9682,30 @@ ix86_expand_epilogue (int style)
ix86_emit_restore_regs_using_pop ();
}
- if (TARGET_SAVE_ARGS) {
- /*
- * For each saved argument, emit a restore note, to make sure it happens
- * correctly within the shrink wrapping (I think).
- *
- * Note that 'restore' in this case merely means the rule is the same as
- * it was on function entry, not that we have actually done a register
- * restore (which of course, we haven't).
- *
- * If we do not do this, the DWARF code will emit sufficient restores to
- * provide balance on its own initiative, which in the presence of
- * -fshrink-wrap may actually _introduce_ unbalance (whereby we only
- * .cfi_offset a register sometimes, but will always .cfi_restore it.
- * This will trip an assert.)
- */
- int start = cfun->returns_struct;
- int nsaved = ix86_nsaved_args();
- int i;
-
- for (i = start + nsaved - 1; i >= start; i--)
- queued_cfa_restores
- = alloc_reg_note (REG_CFA_RESTORE,
+ /*
+ * For each saved argument, emit a restore note, to make sure it happens
+ * correctly within the shrink wrapping (I think).
+ *
+ * Note that 'restore' in this case merely means the rule is the same as
+ * it was on function entry, not that we have actually done a register
+ * restore (which of course, we haven't).
+ *
+ * If we do not do this, the DWARF code will emit sufficient restores to
+ * provide balance on its own initiative, which in the presence of
+ * -fshrink-wrap may actually _introduce_ unbalance (whereby we only
+ * .cfi_offset a register sometimes, but will always .cfi_restore it.
+ * This will trip an assert.)
+ */
+ if (TARGET_SAVE_ARGS && frame.nmsave_args > 0) {
+ int start = cfun->returns_struct;
+ int i;
+
+ for (i = start + frame.nmsave_args - 1; i >= start; i--)
+ queued_cfa_restores
+ = alloc_reg_note (REG_CFA_RESTORE,
gen_rtx_REG(Pmode,
- x86_64_int_parameter_registers[i]),
+ x86_64_int_parameter_registers[i]),
queued_cfa_restores);
-
- gcc_assert(m->fs.fp_valid);
}
/* If we used a stack pointer and haven't already got rid of it,