fd8d687051
Let the assembler handle the low-level details of generating .eh_frame, and use .cfi_escape to output the DWARF3 DW_CFA_def_cfa_expression and DW_CFA_expression instructions. Explicitly output a nop instruction between the FDE start (.cfi_startproc) and the trampoline symbol. x86_64: remove the rsp instruction, which is redundant with the CFA itself. Bug: http://b/169383888 Test: compare `objdump -Wf` output before and after Test: bionic-unit-tests Change-Id: Ie2a6d111cb473596be8c9f4fd64534e91d88f2a1
101 lines
4.1 KiB
C
101 lines
4.1 KiB
C
/*
|
|
* Copyright (C) 2020 The Android Open Source Project
|
|
* All rights reserved.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
* * Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* * Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in
|
|
* the documentation and/or other materials provided with the
|
|
* distribution.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
|
|
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
|
|
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
|
|
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
|
|
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
|
|
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
|
|
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
|
|
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
|
|
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
|
|
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
|
|
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
* SUCH DAMAGE.
|
|
*/
|
|
|
|
// Define assembler macros for generating DWARF CFI instructions that use DWARF expressions.
|
|
// Assemblers don't natively support DWARF expressions, so use the C preprocessor and assembler
|
|
// macros to lower them to .cfi_escape directives.
|
|
//
|
|
// Signal trampolines need to use DWARF expressions to record the locations of saved registers,
|
|
// because the offsets from the restored SP to the saved registers is variable. e.g. A signal frame
|
|
// can have optional FP/SIMD extensions, and there may be extra padding if the interrupted SP wasn't
|
|
// aligned.
|
|
|
|
// DWARF constants.
|
|
#define DW_CFA_def_cfa_expression 0x0f
|
|
#define DW_CFA_expression 0x10
|
|
#define DW_OP_breg0 0x70
|
|
#define DW_OP_deref 0x06
|
|
|
|
// Return the size of a small uleb128 value: either 1 or 2 bytes
|
|
#define ULEB128_14BIT_SIZE(val) \
|
|
(1 + (((val) > 0x7f) & 1))
|
|
|
|
// Return the size of a small sleb128 value: either 1 or 2 bytes
|
|
#define SLEB128_14BIT_SIZE(val) \
|
|
(1 + (((val) < -0x40) & 1) + \
|
|
(((val) > 0x3f) & 1) )
|
|
|
|
// Output a 1 or 2-byte CFI uleb128 absolute value.
|
|
.macro m_cfi_uleb128 val
|
|
.if (\val) < 0 || (\val) > 0x3fff
|
|
.error "m_cfi_uleb128 value is out of range (\val)"
|
|
.elseif (\val) > 0x7f
|
|
.cfi_escape ((\val) & 0x7f) | 0x80
|
|
.cfi_escape (\val) >> 7
|
|
.else
|
|
.cfi_escape (\val)
|
|
.endif
|
|
.endm
|
|
|
|
// Output a 1 or 2-byte CFI sleb128 absolute value.
|
|
.macro m_cfi_sleb128 val
|
|
.if (\val) < -0x2000 || (\val) > 0x1fff
|
|
.error "m_cfi_sleb128 value is out of range (\val)"
|
|
.elseif (\val) < -0x40 || (\val) > 0x3f
|
|
.cfi_escape ((\val) & 0x7f) | 0x80
|
|
.cfi_escape ((\val) >> 7) & 0x7f
|
|
.else
|
|
.cfi_escape (\val) & 0x7f
|
|
.endif
|
|
.endm
|
|
|
|
.macro check_base_reg reg_no
|
|
.if (\reg_no) < 0 || (\reg_no) > 31
|
|
.error "base register is out of range for DW_OP_breg0..DW_OP_breg31 (\reg_no)"
|
|
.endif
|
|
.endm
|
|
|
|
// Set CFA to the expression, *(base_reg + offset)
|
|
.macro m_cfi_def_cfa_deref base_reg, offset
|
|
check_base_reg (\base_reg)
|
|
.cfi_escape DW_CFA_def_cfa_expression
|
|
m_cfi_uleb128 (1 + SLEB128_14BIT_SIZE(\offset) + 1) // size of DWARF expression in bytes
|
|
.cfi_escape DW_OP_breg0 + (\base_reg) // expr: 1 byte
|
|
m_cfi_sleb128 (\offset) // expr: 1 or 2 bytes
|
|
.cfi_escape DW_OP_deref // expr: 1 byte
|
|
.endm
|
|
|
|
// Set the address of the register's previous value to the expression, (base_reg + offset)
|
|
.macro m_cfi_breg_offset dest_reg, base_reg, offset
|
|
check_base_reg (\base_reg)
|
|
.cfi_escape DW_CFA_expression
|
|
m_cfi_uleb128 (\dest_reg)
|
|
m_cfi_uleb128 (1 + SLEB128_14BIT_SIZE(\offset)) // size of DWARF expression in bytes
|
|
.cfi_escape DW_OP_breg0 + (\base_reg) // expr: 1 byte
|
|
m_cfi_sleb128 (\offset) // expr: 1 or 2 bytes
|
|
.endm
|