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8480a37e14
We currently pass frames to function by value, as `frame_info_ptr`.
This is somewhat expensive:
- the size of `frame_info_ptr` is 64 bytes, which is a bit big to pass
by value
- the constructors and destructor link/unlink the object in the global
`frame_info_ptr::frame_list` list. This is an `intrusive_list`, so
it's not so bad: it's just assigning a few points, there's no memory
allocation as if it was `std::list`, but still it's useless to do
that over and over.
As suggested by Tom Tromey, change many function signatures to accept
`const frame_info_ptr &` instead of `frame_info_ptr`.
Some functions reassign their `frame_info_ptr` parameter, like:
void
the_func (frame_info_ptr frame)
{
for (; frame != nullptr; frame = get_prev_frame (frame))
{
...
}
}
I wondered what to do about them, do I leave them as-is or change them
(and need to introduce a separate local variable that can be
re-assigned). I opted for the later for consistency. It might not be
clear why some functions take `const frame_info_ptr &` while others take
`frame_info_ptr`. Also, if a function took a `frame_info_ptr` because
it did re-assign its parameter, I doubt that we would think to change it
to `const frame_info_ptr &` should the implementation change such that
it doesn't need to take `frame_info_ptr` anymore. It seems better to
have a simple rule and apply it everywhere.
Change-Id: I59d10addef687d157f82ccf4d54f5dde9a963fd0
Approved-By: Andrew Burgess <aburgess@redhat.com>
91 lines
3.0 KiB
C
91 lines
3.0 KiB
C
/* Target-dependent header for the Nios II architecture, for GDB.
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Copyright (C) 2012-2024 Free Software Foundation, Inc.
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Contributed by Mentor Graphics, Inc.
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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#ifndef NIOS2_TDEP_H
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#define NIOS2_TDEP_H
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#include "gdbarch.h"
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/* Nios II ISA specific encodings and macros. */
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#include "opcode/nios2.h"
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/* Registers. */
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#define NIOS2_Z_REGNUM 0 /* Zero */
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#define NIOS2_R2_REGNUM 2 /* used for return value */
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#define NIOS2_R3_REGNUM 3 /* used for return value */
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/* Used for hidden zero argument to store ptr to struct return value. */
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#define NIOS2_R4_REGNUM 4
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#define NIOS2_R7_REGNUM 7
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#define NIOS2_GP_REGNUM 26 /* Global Pointer */
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#define NIOS2_SP_REGNUM 27 /* Stack Pointer */
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#define NIOS2_FP_REGNUM 28 /* Frame Pointer */
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#define NIOS2_EA_REGNUM 29 /* Exception address */
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#define NIOS2_BA_REGNUM 30 /* Breakpoint return address */
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#define NIOS2_RA_REGNUM 31 /* Return address */
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#define NIOS2_PC_REGNUM 32
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/* Control registers. */
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#define NIOS2_STATUS_REGNUM 33
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#define NIOS2_ESTATUS_REGNUM 34
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#define NIOS2_BSTATUS_REGNUM 35
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#define NIOS2_IENABLE_REGNUM 36
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#define NIOS2_IPENDING_REGNUM 37
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#define NIOS2_CPUID_REGNUM 38
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#define NIOS2_EXCEPTION_REGNUM 40
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#define NIOS2_PTEADDR_REGNUM 41
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#define NIOS2_TLBACC_REGNUM 42
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#define NIOS2_TLBMISC_REGNUM 43
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#define NIOS2_ECCINJ_REGNUM 44
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#define NIOS2_BADADDR_REGNUM 45
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#define NIOS2_CONFIG_REGNUM 46
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#define NIOS2_MPUBASE_REGNUM 47
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#define NIOS2_MPUACC_REGNUM 48
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/* R4-R7 are used for argument passing. */
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#define NIOS2_FIRST_ARGREG NIOS2_R4_REGNUM
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#define NIOS2_LAST_ARGREG NIOS2_R7_REGNUM
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/* Number of all registers. */
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#define NIOS2_NUM_REGS 49
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/* Size of an instruction, in bytes. */
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#define NIOS2_OPCODE_SIZE 4
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#define NIOS2_CDX_OPCODE_SIZE 2
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/* Target-dependent structure in gdbarch. */
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struct nios2_gdbarch_tdep : gdbarch_tdep_base
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{
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/* Assumes FRAME is stopped at a syscall (trap) instruction; returns
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the expected next PC. */
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CORE_ADDR (*syscall_next_pc) (const frame_info_ptr &frame,
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const struct nios2_opcode *op) = nullptr;
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/* Returns true if PC points to a kernel helper function. */
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bool (*is_kernel_helper) (CORE_ADDR pc) = nullptr;
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/* Offset to PC value in jump buffer.
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If this is negative, longjmp support will be disabled. */
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int jb_pc = 0;
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};
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extern const struct target_desc *tdesc_nios2_linux;
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extern const struct target_desc *tdesc_nios2;
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#endif /* NIOS2_TDEP_H */
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