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-rw-r--r--tools/fdegen/main.cpp372
1 files changed, 372 insertions, 0 deletions
diff --git a/tools/fdegen/main.cpp b/tools/fdegen/main.cpp
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+++ b/tools/fdegen/main.cpp
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+/****************************************************************************
+**
+** Copyright (C) 2012 Digia Plc and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of the V4VM module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and Digia. For licensing terms and
+** conditions see http://qt.digia.com/licensing. For further information
+** use the contact form at http://qt.digia.com/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Digia gives you certain additional
+** rights. These rights are described in the Digia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3.0 as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU General Public License version 3.0 requirements will be
+** met: http://www.gnu.org/copyleft/gpl.html.
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include <libdwarf.h>
+#include <dwarf.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+#define DEBUG
+
+#ifdef DEBUG
+#include <libelf.h>
+#endif
+
+#include <qglobal.h>
+
+enum DwarfRegs {
+#if defined(Q_PROCESSOR_X86_64)
+ // X86-64
+ RAX = 0,
+ RDX = 1,
+ RCX = 2,
+ RBX = 3,
+ RSI = 4,
+ RDI = 5,
+ RBP = 6,
+ RSP = 7,
+ R8 = 8,
+ R9 = 9,
+ R10 = 10,
+ R11 = 11,
+ R12 = 12,
+ R13 = 13,
+ R14 = 14,
+ R15 = 15,
+ RIP = 16,
+
+ InstructionPointerRegister = RIP,
+ StackPointerRegister = RSP,
+ StackFrameRegister = RBP
+#elif defined(Q_PROCESSOR_X86)
+ // x86
+ EAX = 0,
+ EDX = 1,
+ ECX = 2,
+ EBX = 3,
+ ESI = 4,
+ EDI = 5,
+ EBP = 6,
+ ESP = 7,
+ EIP = 8,
+
+ InstructionPointerRegister = EIP,
+ StackPointerRegister = ESP,
+ StackFrameRegister = EBP
+#else
+#error Not ported yet
+#endif
+};
+
+static const DwarfRegs calleeSavedRegisters[] = {
+#if defined(Q_PROCESSOR_X86_64)
+ R12,
+ R14
+#endif
+};
+static const int calleeSavedRegisterCount = sizeof(calleeSavedRegisters) / sizeof(calleeSavedRegisters[0]);
+
+#if QT_POINTER_SIZE == 8
+#define Elf_Ehdr Elf64_Ehdr
+#define elf_newehdr elf64_newehdr
+#define Elf_Shdr Elf64_Shdr
+#define elf_getshdr elf64_getshdr
+#else
+#define Elf_Ehdr Elf32_Ehdr
+#define elf_newehdr elf32_newehdr
+#define Elf_Shdr Elf32_Shdr
+#define elf_getshdr elf32_getshdr
+#endif
+
+static void die(const char *msg)
+{
+ fprintf(stderr, "error: %s\n", msg);
+ exit(1);
+}
+
+static int createSectionCallback(
+ char *name,
+ int size,
+ Dwarf_Unsigned /*type*/,
+ Dwarf_Unsigned /*flags*/,
+ Dwarf_Unsigned /*link*/,
+ Dwarf_Unsigned /*info*/,
+ Dwarf_Unsigned* /*sect_name_index*/,
+ void * /*user_data*/,
+ int* /*error*/)
+{
+ if (strcmp(name, ".debug_frame"))
+ return 0;
+ fprintf(stderr, "createsection called with %s and size %d\n", name, size);
+ return 1;
+}
+
+static unsigned char cie_init_instructions[] = {
+ DW_CFA_def_cfa, StackPointerRegister, /*offset in bytes */QT_POINTER_SIZE,
+ DW_CFA_offset | InstructionPointerRegister, 1,
+};
+
+int main()
+{
+ Dwarf_Error error = 0;
+ Dwarf_P_Debug dw = dwarf_producer_init_c(DW_DLC_WRITE | DW_DLC_SIZE_64,
+ createSectionCallback,
+ /* error handler */0,
+ /* error arg */0,
+ /* user data */0,
+ &error);
+ if (error != 0)
+ die("dwarf_producer_init_c failed");
+
+ Dwarf_Unsigned cie = dwarf_add_frame_cie(dw,
+ "",
+ /* code alignment factor */QT_POINTER_SIZE,
+ /* data alignment factor */-QT_POINTER_SIZE,
+ /* return address reg*/InstructionPointerRegister,
+ cie_init_instructions,
+ sizeof(cie_init_instructions),
+ &error);
+ if (error != 0)
+ die("dwarf_add_frame_cie failed");
+
+ Dwarf_P_Fde fde = dwarf_new_fde(dw, &error);
+ if (error != 0)
+ die("dwarf_new_fde failed");
+
+ /* New entry in state machine for code offset 1 after push rbp instruction */
+ dwarf_add_fde_inst(fde,
+ DW_CFA_advance_loc,
+ /*offset in code alignment units*/ 1,
+ /* unused*/ 0,
+ &error);
+
+ /* After "push rbp" the offset to the CFA is now 2 instead of 1 */
+ dwarf_add_fde_inst(fde,
+ DW_CFA_def_cfa_offset_sf,
+ /*offset in code alignment units*/ -2,
+ /* unused*/ 0,
+ &error);
+
+ /* After "push rbp" the value of rbp is now stored at offset 1 from CFA */
+ dwarf_add_fde_inst(fde,
+ DW_CFA_offset,
+ StackFrameRegister,
+ 2,
+ &error);
+
+ /* New entry in state machine for code offset 3 for mov rbp, rsp instruction */
+ dwarf_add_fde_inst(fde,
+ DW_CFA_advance_loc,
+ /*offset in code alignment units*/ 3,
+ /* unused */ 0,
+ &error);
+
+ /* After "mov rbp, rsp" the cfa is reachable via rbp */
+ dwarf_add_fde_inst(fde,
+ DW_CFA_def_cfa_register,
+ StackFrameRegister,
+ /* unused */0,
+ &error);
+
+ /* Callee saved registers */
+ for (int i = 0; i < calleeSavedRegisterCount; ++i) {
+ dwarf_add_fde_inst(fde,
+ DW_CFA_offset,
+ calleeSavedRegisters[i],
+ i + 3,
+ &error);
+ }
+
+ dwarf_add_frame_fde(dw, fde,
+ /* die */0,
+ cie,
+ /*virt addr */0,
+ /* length of code */0,
+ /* symbol index */0,
+ &error);
+ if (error != 0)
+ die("dwarf_add_frame_fde failed");
+
+ dwarf_transform_to_disk_form(dw, &error);
+ if (error != 0)
+ die("dwarf_transform_to_disk_form failed");
+
+ Dwarf_Unsigned len = 0;
+ Dwarf_Signed elfIdx = 0;
+ unsigned char *bytes = (unsigned char *)dwarf_get_section_bytes(dw, /* section */1,
+ &elfIdx, &len, &error);
+ if (error != 0)
+ die("dwarf_get_section_bytes failed");
+
+ // libdwarf doesn't add a terminating FDE with zero length, so let's add one
+ // ourselves.
+ unsigned char *newBytes = (unsigned char *)alloca(len + 4);
+ memcpy(newBytes, bytes, len);
+ newBytes[len] = 0;
+ newBytes[len + 1] = 0;
+ newBytes[len + 2] = 0;
+ newBytes[len + 3] = 0;
+ newBytes[len + 4] = 0;
+ bytes = newBytes;
+ len += 4;
+
+ // Reset CIE-ID back to 0 as expected for .eh_frames
+ bytes[4] = 0;
+ bytes[5] = 0;
+ bytes[6] = 0;
+ bytes[7] = 0;
+
+ unsigned fde_offset = bytes[0] + 4;
+
+ bytes[fde_offset + 4] = fde_offset + 4;
+
+ printf("static const unsigned char cie_fde_data[] = {\n");
+ int i = 0;
+ while (i < len) {
+ printf(" ");
+ for (int j = 0; i < len && j < 8; ++j, ++i)
+ printf("0x%x, ", bytes[i]);
+ printf("\n");
+ }
+ printf("};\n");
+
+ printf("static const int fde_offset = %d;\n", fde_offset);
+ printf("static const int initial_location_offset = %d;\n", fde_offset + 8);
+ printf("static const int address_range_offset = %d;\n", fde_offset + 8 + QT_POINTER_SIZE);
+
+#ifdef DEBUG
+ {
+ if (elf_version(EV_CURRENT) == EV_NONE)
+ die("wrong elf version");
+ int fd = open("debug.o", O_WRONLY | O_CREAT, 0777);
+ if (fd < 0)
+ die("cannot create debug.o");
+
+ Elf *e = elf_begin(fd, ELF_C_WRITE, 0);
+ if (!e)
+ die("elf_begin failed");
+
+ Elf_Ehdr *ehdr = elf_newehdr(e);
+ if (!ehdr)
+ die(elf_errmsg(-1));
+
+ ehdr->e_ident[EI_DATA] = ELFDATA2LSB;
+#if defined(Q_PROCESSOR_X86_64)
+ ehdr->e_machine = EM_X86_64;
+#elif defined(Q_PROCESSOR_X86)
+ ehdr->e_machine = EM_386;
+#else
+#error port me :)
+#endif
+ ehdr->e_type = ET_EXEC;
+ ehdr->e_version = EV_CURRENT;
+
+ Elf_Scn *section = elf_newscn(e);
+ if (!section)
+ die("elf_newscn failed");
+
+ Elf_Data *data = elf_newdata(section);
+ if (!data)
+ die(elf_errmsg(-1));
+ data->d_align = 4;
+ data->d_off = 0;
+ data->d_buf = bytes;
+ data->d_size = len;
+ data->d_type = ELF_T_BYTE;
+ data->d_version = EV_CURRENT;
+
+ Elf_Shdr *shdr = elf_getshdr(section);
+ if (!shdr)
+ die(elf_errmsg(-1));
+
+ shdr->sh_name = 1;
+ shdr->sh_type = SHT_PROGBITS;
+ shdr->sh_entsize = 0;
+
+ char stringTable[] = {
+ 0,
+ '.', 'e', 'h', '_', 'f', 'r', 'a', 'm', 'e', 0,
+ '.', 's', 'h', 's', 't', 'r', 't', 'a', 'b', 0
+ };
+
+ section = elf_newscn(e);
+ if (!section)
+ die("elf_newscn failed");
+
+ data = elf_newdata(section);
+ if (!data)
+ die(elf_errmsg(-1));
+ data->d_align = 1;
+ data->d_off = 0;
+ data->d_buf = stringTable;
+ data->d_size = sizeof(stringTable);
+ data->d_type = ELF_T_BYTE;
+ data->d_version = EV_CURRENT;
+
+ shdr = elf_getshdr(section);
+ if (!shdr)
+ die(elf_errmsg(-1));
+
+ shdr->sh_name = 11;
+ shdr->sh_type = SHT_STRTAB;
+ shdr->sh_flags = SHF_STRINGS | SHF_ALLOC;
+ shdr->sh_entsize = 0;
+
+ ehdr->e_shstrndx = elf_ndxscn(section);
+
+ if (elf_update(e, ELF_C_WRITE) < 0)
+ die(elf_errmsg(-1));
+
+ elf_end(e);
+ close(fd);
+ }
+#endif
+
+ dwarf_producer_finish(dw, &error);
+ if (error != 0)
+ die("dwarf_producer_finish failed");
+ return 0;
+}
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