Gcc的spec中arch什么的指定

日期：2020-06-08 栏目：程序人生浏览：次

gcc/gcc.c中的set_collect_gcc_options这里面有COLLECT_GCC_OPTIONS='-march=armv4t' '-mtune=arm920t

(gdb) p switches[0]
$15 = {part1 = 0x80792b1 "march=armv4t", args = 0x0, live_cond = 1,
validated = 1 '\001', ordering = 0 '\000'}
(gdb) p switches[1]
$16 = {part1 = 0x80792c1 "mtune=arm920t", args = 0x0, live_cond = 0,
validated = 1 '\001', ordering = 0 '\000'}
(gdb) p switches[2]
$17 = {part1 = 0x80792d1 "mfloat-abi=soft", args = 0x0, live_cond = 0,
validated = 1 '\001', ordering = 0 '\000'}
(gdb) p switches[3]
$18 = {part1 = 0x0, args = 0xf7fb3420, live_cond = 1768697683,
validated = 98 'b', ordering = 47 '/'}
(gdb) p n_switches
$19 = 3

switches的赋值在do_self_spec和process_command

多次调用do_self_spec

Breakpoint 1, do_self_spec (
    spec=0xffffd150 "%{!march=*:%{!mcpu=*:-mcpu=arm920t}}")
    at ../../gcc-4.4.5/gcc/gcc.c:4614
4614      do_spec_2 (spec);

Breakpoint 1, do_self_spec (
    spec=0xffffd150 "%{!march=*:%{!mcpu=*:-march=armv4t}}")
    at ../../gcc-4.4.5/gcc/gcc.c:4614
4614      do_spec_2 (spec);

bt的结果为：

(gdb) bt
#0 do_self_spec (spec=0xffffd150 "%{!march=*:%{!mcpu=*:-mcpu=arm920t}}")
    at ../../gcc-4.4.5/gcc/gcc.c:4614
#1 0x080523e2 in do_option_spec (name=<value optimized out>,
    spec=<value optimized out>) at ../../gcc-4.4.5/gcc/gcc.c:4605
#2 0x0805349b in main (argc=2, argv=0xffffd334)
    at ../../gcc-4.4.5/gcc/gcc.c:6376

现在我看来看看main函数是怎么调用do_option_spec的

Breakpoint 2, do_option_spec (name=0x805f57a "tune",
    spec=0x8062370 "%{!mcpu=*:%{!mtune=*:-mtune=%(VALUE)}} ")
    at ../../gcc-4.4.5/gcc/gcc.c:4572
4572      for (i = 0; i < ARRAY_SIZE (configure_default_options); i++)
(gdb) c
Continuing.

Breakpoint 1, do_self_spec (
    spec=0xffffd150 "%{!mcpu=*:%{!mtune=*:-mtune=arm920t}} ")
    at ../../gcc-4.4.5/gcc/gcc.c:4614
4614      do_spec_2 (spec);
看到转变了吧，我说调用gcc的 -dumpspecs找不到arm920t这样的关键字。。。

在do_option_spec中的configure_default_options

(gdb) p configure_default_options
$23 = {{name = 0x805f576 "cpu", value = 0x805fdf8 "arm920t"}, {
    name = 0x805f571 "arch", value = 0x805fe00 "armv4t"}, {
    name = 0x805f57a "tune", value = 0x805fdf8 "arm920t"}, {
    name = 0x8066f0a "float", value = 0x8066fb1 "soft"}}

configure_default_option是哪来的呢

cat > configargs.h <<EOF
/* Generated automatically. */
static const char configuration_arguments[] = "$gcc_config_arguments_str";
static const char thread_model[] = "$thread_file";

static const struct {
const char *name, *value;
} configure_default_options[] = $configure_default_options;
EOF

specs文件要放在

gcc -print-libgcc-file-name这个文件所在的文件夹中。

现在，用Android里的编译器改下specs就可以编译在mini2440上跑的android了嘿嘿。

不过目前还不知道android调用哪个版本的编译器。。。

说到这还是不知道怎么编辑specs文件我们再来看看在main函数中是怎么调用do_option_spec的

Breakpoint 1, do_option_spec (name=0x805f571 "arch",
    spec=0x8062320 "%{!march=*:%{!mcpu=*:-march=%(VALUE)}}")
    at ../../gcc-4.4.5/gcc/gcc.c:4572
4572    ../../gcc-4.4.5/gcc/gcc.c: No such file or directory.
    in ../../gcc-4.4.5/gcc/gcc.c

static void do_option_spec (const char *name, const char *spec)

在main函数中

for (i = 0; i < ARRAY_SIZE (option_default_specs); i++)
do_option_spec (option_default_specs[i].name,
option_default_specs[i].spec);

(gdb) p option_default_specs
$1 = {{name = 0x805f571 "arch",
    spec = 0x8062320 "%{!march=*:%{!mcpu=*:-march=%(VALUE)}}"}, {
    name = 0x805f576 "cpu",
    spec = 0x8062348 "%{!march=*:%{!mcpu=*:-mcpu=%(VALUE)}}"}, {
    name = 0x805f57a "tune",
    spec = 0x8062370 "%{!mcpu=*:%{!mtune=*:-mtune=%(VALUE)}}"}, {
    name = 0x8066f0a "float",
    spec = 0x8062398 "%{!msoft-float:%{!mhard-float:%{!mfloat-abi=*:-mfloat-abi=%(VALUE)}}}"}, {name = 0x805f57f "fpu",
    spec = 0x805f583 "%{!mfpu=*:-mfpu=%(VALUE)}"}, {name = 0x8065fd3 "abi",
    spec = 0x805f59d "%{!mabi=*:-mabi=%(VALUE)}"}, {name = 0x805f5b7 "mode",
    spec = 0x80623e0 "%{!marm:%{!mthumb:-m%(VALUE)}}"}}

static const struct default_spec
option_default_specs[] = { OPTION_DEFAULT_SPECS };

OPTION_DEFAULT_SPECS在gcc/config/arm/arm.h中定义

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Gcc的spec中arch什么的指定

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