tl;dr
我如何将Ada源代码编译成适用于在运行iOS的iPad目标应用程序中链接的静态库文件？（GCC不是必需的。使用LLVM或其他解决方案也可以！）
我拥有一个大型可移植的Ada代码库，我想在iPad/iOS项目中使用它。我的主机操作系统是Mac OS X 10.9（安装了MacPorts中的GCC 4.8.1）。为此，我正在尝试构建带有Ada支持的GCC ARM交叉编译器。
我能够构建创建ARM可执行文件的工作GCC和GNAT，但似乎无法构建或安装Ada标准库，这是构建我的Ada代码所必需的。
我正在使用的源包：
gcc-4.8.1
binutils-2.24
libiconv-1.14
gmp-5.1.3
mpc-1.0.2
mpfr-3.1.2
GCC的构建配置：
$ bin/arm-none-eabi-gcc -v --version
Using built-in specs.
COLLECT_GCC=bin/arm-none-eabi-gcc
COLLECT_LTO_WRAPPER=/Users/ardnew/cross/libexec/gcc/arm-none-eabi/4.8.1/lto-wrapper
arm-none-eabi-gcc (GCC) 4.8.1
Copyright (C) 2013 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
Target: arm-none-eabi
Configured with: /Users/ardnew/cross/src/gcc-4.8.1/configure --target=arm-none-eabi --prefix=/Users/ardnew/cross --with-cpu=cortex-a8 --enable-languages=c,ada --disable-multilib --enable-interwork --disable-threads --disable-shared --disable-nls --disable-lto --disable-libssp --disable-decimal-float --disable-libgomp --disable-libmudflap
Thread model: single
gcc version 4.8.1 (GCC)
COLLECT_GCC_OPTIONS='-v' '--version' '-mcpu=cortex-a8'
/Users/ardnew/cross/libexec/gcc/arm-none-eabi/4.8.1/cc1 -quiet -v -D__USES_INITFINI__ help-dummy -quiet -dumpbase help-dummy -mcpu=cortex-a8 -auxbase help-dummy -version --version -o /var/folders/4c/y_sll7bj6b9bt15389wr66_80000gn/T//ccrSSKFx.s
GNU C (GCC) version 4.8.1 (arm-none-eabi)
compiled by GNU C version 4.8.1, GMP version 5.1.3, MPFR version 3.1.2, MPC version 1.0.2
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
COLLECT_GCC_OPTIONS='-v' '--version' '-mcpu=cortex-a8'
/Users/ardnew/cross/lib/gcc/arm-none-eabi/4.8.1/../../../../arm-none-eabi/bin/as -mcpu=cortex-a8 -meabi=5 --version -o /var/folders/4c/y_sll7bj6b9bt15389wr66_80000gn/T//ccZYvQLp.o /var/folders/4c/y_sll7bj6b9bt15389wr66_80000gn/T//ccrSSKFx.s
GNU assembler (GNU Binutils) 2.24
Copyright 2013 Free Software Foundation, Inc.
This program is free software; you may redistribute it under the terms of
the GNU General Public License version 3 or later.
This program has absolutely no warranty.
This assembler was configured for a target of `arm-none-eabi'.
COMPILER_PATH=/Users/ardnew/cross/libexec/gcc/arm-none-eabi/4.8.1/:/Users/ardnew/cross/libexec/gcc/arm-none-eabi/4.8.1/:/Users/ardnew/cross/libexec/gcc/arm-none-eabi/:/Users/ardnew/cross/lib/gcc/arm-none-eabi/4.8.1/:/Users/ardnew/cross/lib/gcc/arm-none-eabi/:/Users/ardnew/cross/lib/gcc/arm-none-eabi/4.8.1/../../../../arm-none-eabi/bin/
LIBRARY_PATH=/Users/ardnew/cross/lib/gcc/arm-none-eabi/4.8.1/:/Users/ardnew/cross/lib/gcc/arm-none-eabi/4.8.1/../../../../arm-none-eabi/lib/
COLLECT_GCC_OPTIONS='-v' '--version' '-mcpu=cortex-a8'
/Users/ardnew/cross/libexec/gcc/arm-none-eabi/4.8.1/collect2 -X --version /Users/ardnew/cross/lib/gcc/arm-none-eabi/4.8.1/crti.o /Users/ardnew/cross/lib/gcc/arm-none-eabi/4.8.1/crtbegin.o crt0.o -L/Users/ardnew/cross/lib/gcc/arm-none-eabi/4.8.1 -L/Users/ardnew/cross/lib/gcc/arm-none-eabi/4.8.1/../../../../arm-none-eabi/lib /var/folders/4c/y_sll7bj6b9bt15389wr66_80000gn/T//ccZYvQLp.o --start-group -lgcc -lc --end-group /Users/ardnew/cross/lib/gcc/arm-none-eabi/4.8.1/crtend.o /Users/ardnew/cross/lib/gcc/arm-none-eabi/4.8.1/crtn.o
collect2 version 4.8.1
/Users/ardnew/cross/lib/gcc/arm-none-eabi/4.8.1/../../../../arm-none-eabi/bin/ld -X --version /Users/ardnew/cross/lib/gcc/arm-none-eabi/4.8.1/crti.o /Users/ardnew/cross/lib/gcc/arm-none-eabi/4.8.1/crtbegin.o crt0.o -L/Users/ardnew/cross/lib/gcc/arm-none-eabi/4.8.1 -L/Users/ardnew/cross/lib/gcc/arm-none-eabi/4.8.1/../../../../arm-none-eabi/lib /var/folders/4c/y_sll7bj6b9bt15389wr66_80000gn/T//ccZYvQLp.o --start-group -lgcc -lc --end-group /Users/ardnew/cross/lib/gcc/arm-none-eabi/4.8.1/crtend.o /Users/ardnew/cross/lib/gcc/arm-none-eabi/4.8.1/crtn.o
GNU ld (GNU Binutils) 2.24
Copyright 2013 Free Software Foundation, Inc.
This program is free software; you may redistribute it under the terms of
the GNU General Public License version 3 or (at your option) a later version.
This program has absolutely no warranty.
测试程序以确保构建ARM二进制文件:
$ cat told_unit1.adb told_unit1.ads
--
-- FILE: told_unit1.adb
--
with Ada.Text_IO;
use Ada.Text_IO;
package body told_unit1 is
procedure hello is
begin
put_line("hello, world");
end hello;
function double(x : in float) return float is
begin
return x + x;
end double;
end told_unit1;
--
-- FILE: told_unit1.ads
--
package told_unit1 is
procedure hello;
pragma Export
(
convention => C,
entity => hello,
external_name => "ada_hello"
);
function double(x : in float) return float;
pragma Export
(
convention => C,
entity => double,
external_name => "ada_double"
);
end told_unit1;
然后编译Ada代码并使用file检查它：
$ arm-none-eabi-gcc -c told_unit1.adb
$ file told_unit1.o
told_unit1.o: ELF 32-bit LSB relocatable, ARM, version 1 (SYSV), not stripped
然后当我尝试绑定库对象文件时，它会出错：
$ arm-none-eabi-gnatbind -aO$ADA_OBJECT_PATH -Ltold told_unit1
error: "a-textio.ali" not found, "a-textio.adb" must be compiled
回顾我的GCC构建日志，我发现libada（我相信它是GNAT的一部分）从未被构建。当我尝试从GCC构建目录运行
make all-target-libada时，它最终告诉我：Configuring in arm-none-eabi/libada
configure: loading cache ./config.cache
checking build system type... x86_64-apple-darwin13.1.0
checking host system type... arm-none-eabi
checking target system type... arm-none-eabi
checking for arm-none-eabi-gcc... /Users/ardnew/cross/src/gcc-4.8.1-obj/./gcc/xgcc -B/Users/ardnew/cross/src/gcc-4.8.1-obj/./gcc/ -B/Users/ardnew/cross/arm-none-eabi/bin/ -B/Users/ardnew/cross/arm-none-eabi/lib/ -isystem /Users/ardnew/cross/arm-none-eabi/include -isystem /Users/ardnew/cross/arm-none-eabi/sys-include
checking for C compiler default output file name...
configure: error: in `/Users/ardnew/cross/src/gcc-4.8.1-obj/arm-none-eabi/libada':
configure: error: C compiler cannot create executables
See `config.log' for more details.
make: *** [configure-target-libada] Error 1
于是我检查了它所提到的config.log，发现如下内容：
configure:2351: $? = 0
configure:2340: /Users/ardnew/cross/src/gcc-4.8.1-obj/./gcc/xgcc -B/Users/ardnew/cross/src/gcc-4.8.1-obj/./gcc/ -B/Users/ardnew/cross/arm-none-eabi/bin/ -B/Users/ardnew/cross/arm-none-eabi/lib/ -isystem /Users/ardnew/cross/arm-none-eabi/include -isystem /Users/ardnew/cross/arm-none-eabi/sys-include -v >&5
COLLECT_LTO_WRAPPER=/Users/ardnew/cross/src/gcc-4.8.1-obj/./gcc/lto-wrapper
Target: arm-none-eabi
Configured with: /Users/ardnew/cross/src/gcc-4.8.1/configure --target=arm-none-eabi --prefix=/Users/ardnew/cross --with-cpu=cortex-a8 --enable-languages=c,ada --disable-multilib --enable-interwork --disable-threads --disable-shared --disable-nls --disable-lto --disable-libssp --disable-decimal-float --disable-libgomp --disable-libmudflap
configure:2351: $? = 0
xgcc: error: unrecognized command line option '-qversion'
xgcc: fatal error: no input files
compilation terminated.
configure:2351: $? = 1
configure:2371: checking for C compiler default output file name
configure:2393: /Users/ardnew/cross/src/gcc-4.8.1-obj/./gcc/xgcc -B/Users/ardnew/cross/src/gcc-4.8.1-obj/./gcc/ -B/Users/ardnew/cross/arm-none-eabi/bin/ -B/Users/ardnew/cross/arm-none-eabi/lib/ -isystem /Users/ardnew/cross/arm-none-eabi/include -isystem /Users/ardnew/cross/arm-none-eabi/sys-include -g -O2 conftest.c >&5
/Users/ardnew/cross/arm-none-eabi/bin/ld: cannot find crt0.o: No such file or directory
/Users/ardnew/cross/arm-none-eabi/bin/ld: cannot find -lg
/Users/ardnew/cross/arm-none-eabi/bin/ld: cannot find -lc
collect2: error: ld returned 1 exit status
configure:2397: $? = 1
configure:2434: result:
configure: failed program was:
| /* confdefs.h */
| #define PACKAGE_NAME ""
| #define PACKAGE_TARNAME ""
| #define PACKAGE_VERSION ""
| #define PACKAGE_STRING ""
| #define PACKAGE_BUGREPORT ""
| #define PACKAGE_URL ""
| /* end confdefs.h. */
|
| int
| main ()
| {
|
| ;
| return 0;
| }
configure:2440: error: in `/Users/ardnew/cross/src/gcc-4.8.1-obj/arm-none-eabi/libada':
configure:2444: error: C compiler cannot create executables
See `config.log' for more details.
现在我已经超出了自己的能力范围，不太确定接下来该怎么办。看起来我可能缺少ARM平台的C运行时库？
如果有任何帮助配置GNAT/libada用于ARM目标的方法，那就太好了。
或者，是否有更简单的方法从Xcode iOS项目中链接到Ada库？
arm-none-eabi交叉编译器是否生成 ELF 或 Macho 二进制文件 - 后者在 MacOSX 上都是必需的，但我强烈怀疑配置会生成 ELF，而你无法使用。这不是一个很大的问题，但你可能需要自己构建一个带有 Mach-o 支持的交叉编译 GCC 和 bin-utils。 - markoarm-apple-darwin-前缀或类似的内容。您的错误很可能与可执行文件格式不匹配有关。 - marko