Getting started with GCC - Revision history

Lvosandi at 12:00, 13 October 2016

2016-10-13T12:00:42Z

← Older revision		Revision as of 15:00, 13 October 2016
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	cat libfib.s		cat libfib.s

	~~Follow the~~ [https://~~www~~.ic.~~unicamp~~.br/~~~ranido/mc404/arm/arm-instructionset~~.~~pdf~~ ARM mnemonics ~~list on page 3]~~ and ~~try to understand what goes on inside the processor with execution of each instruction~~.		If most of this make sense so far, try to do some [https://wiki.itcollege.ee/index.php/Category:I600_Introduction_to_Computers_and_Informatics#Assignment:_Investigating_compilers exercises]. ARM mnemonics and all relevant links are there.

Lvosandi: /* Makefiles */

2015-10-15T13:51:10Z

Makefiles

← Older revision		Revision as of 16:51, 15 October 2015
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	CROSSCOMPILE=arm-linux-gnueabihf- make hello		CROSSCOMPILE=arm-linux-gnueabihf- make hello

			Generate ARM assembly for the function of calculating Fibonacci numbers:

			CROSSCOMPILE=arm-linux-gnueabihf- make libfib.s

			Store it for later:

			cat libfib.s

			Follow the [https://www.ic.unicamp.br/~ranido/mc404/arm/arm-instructionset.pdf ARM mnemonics list on page 3] and try to understand what goes on inside the processor with execution of each instruction.

Lvosandi: /* Compiling assembly */

2015-10-15T13:45:02Z

Compiling assembly

← Older revision		Revision as of 16:45, 15 October 2015
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	Investigate the assembly corresponding to <code>fib</code>:		Investigate the assembly corresponding to <code>fib</code>:

	~~gcc -static~~ libfib.~~c hello.c -o hello-simple-static~~		cat libfib.s



	== Dynamic vs static linking ==		== Dynamic vs static linking ==

Lvosandi: /* Sample source files */

2015-10-15T13:21:30Z

Sample source files

← Older revision		Revision as of 16:21, 15 October 2015
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	} else {		} else {
	int n;		int n;
	sscanf("%d"~~, argv[1]~~, &n);		sscanf(argv[1], "%d", &n);
	printf("%dth fibonacci number is %d\n", n, fib(n));		printf("%dth fibonacci number is %d\n", n, fib(n));
	return 0;		return 0;

Lvosandi at 13:19, 15 October 2015

2015-10-15T13:19:25Z

← Older revision		Revision as of 16:19, 15 October 2015
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	}		}

	Create another plain-text file to invoke the function described above:		Create another plain-text file <code>hello.c</code> to invoke the function described above:

	#include <stdio.h>		#include <stdio.h>

Lvosandi at 12:03, 15 October 2015

2015-10-15T12:03:58Z

← Older revision		Revision as of 15:03, 15 October 2015
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	The point of this article is to get familiar with tools provided by GCC toolchain.		The point of this article is to get familiar with tools provided by GCC toolchain.
	GCC, especially as a cross-compiler is widely used to compile firmware for Raspberry Pi, Arduino, Ubuntu, routers and other embedded devices.		GCC, especially as a cross-compiler is widely used to compile firmware for [[Getting started with Raspberry Pi\|Raspberry Pi]], Arduino, Ubuntu, routers and other embedded devices.
	You can also manually compile a compiler for foreign architectures which isn't supported out of the box for your distribution,		You can also manually compile a compiler for foreign architectures which isn't supported out of the box for your distribution,
	see [http://lauri.vosandi.com/tub/computer-architecture/building-mips-toolchain.html here] for more information		see [http://lauri.vosandi.com/tub/computer-architecture/building-mips-toolchain.html here] for more information

Lvosandi at 12:01, 15 October 2015

2015-10-15T12:01:04Z

← Older revision		Revision as of 15:01, 15 October 2015
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	The point of this article is to get familiar with tools provided by GCC toolchain.		The point of this article is to get familiar with tools provided by GCC toolchain.
	GCC, especially as a cross-compiler is widely used to compile firmware for routers and other embedded devices.		GCC, especially as a cross-compiler is widely used to compile firmware for Raspberry Pi, Arduino, Ubuntu, routers and other embedded devices.
	You can also manually compile a compiler for foreign architectures which isn't supported out of the box for your distribution,		You can also manually compile a compiler for foreign architectures which isn't supported out of the box for your distribution,
	see [http://lauri.vosandi.com/tub/computer-architecture/building-mips-toolchain.html here] for more information		see [http://lauri.vosandi.com/tub/computer-architecture/building-mips-toolchain.html here] for more information

Lvosandi at 11:39, 15 October 2015

2015-10-15T11:39:04Z

← Older revision		Revision as of 14:39, 15 October 2015
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	objdump -D mylibs/libfib-native.so		objdump -D mylibs/libfib-native.so


			== Cross-compiling ==

			Use ARM cross-compiler to compile ARM binaries on x86:

			arm-linux-gnueabihf-gcc libfib.c hello.c -static -o hello-foreign

			Use <code>file</code>, <code>ldd</code> and <code>objdump</code> to inspect the binary.
			Assuming <code>binfmt-support</code> has been set up properly and QEMU emulation layer is available a static ARM binary can be invoked on x86 host via emulation:

			./hello-foreign

			For dynamically linked binaries you need also dependant libraries, the simplest way is to bootstrap a [http://lauri.vosandi.com/cfgmgmt/linux-containers.html#voora-arhitektuuriga-konteinerid LXC container for ARM].



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	make		make

	~~== Cross-compiling ==~~		To clean binaries:

	~~Use ARM cross-compiler to compile ARM~~ binaries ~~on x86~~:

	~~arm-linux-gnueabihf-gcc libfib.c hello.c -static -o hello-foreign~~

	~~Use <code>file</code>, <code>ldd</code> and <code>objdump</code> to inspect the binary.~~		make clean
	~~Assuming <code>binfmt-support</code> has been set up properly and QEMU emulation layer is available a static ARM binary can be invoked on x86 host via emulation:~~

	~~./hello~~-~~foreign~~		To cross-compile:

	~~For dynamically linked binaries you need also dependant libraries, the simplest way is to bootstrap a [http://lauri.vosandi.com/cfgmgmt/~~linux-~~containers.html#voora-arhitektuuriga~~-~~konteinerid LXC container for ARM].~~		CROSSCOMPILE=arm-linux-gnueabihf- make hello

Lvosandi: /* Makefiles */

2015-10-15T11:37:33Z

Makefiles

← Older revision		Revision as of 14:37, 15 October 2015
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	Makefiles are used to simplify building a software project.		Makefiles are used to simplify building a software project.
	[http://ant.apache.org/ Ant] is a corresponding tool for Java ~~project~~.		[http://ant.apache.org/ Ant] is a corresponding tool for Java projects.
	[https://maven.apache.org/] complements Ant with automatic JAR downloading capabilities.		[https://maven.apache.org/ Maven] complements Ant with automatic JAR downloading capabilities.
	Python does dependency tracking already internally, <code>pip</code> also installs dependant libraries if ~~necesary~~.		Python does dependency tracking already internally, <code>pip</code> also installs dependant libraries if necessary.

	Create file <code>Makefile</code>:		Create file <code>Makefile</code>:

Lvosandi at 11:36, 15 October 2015

2015-10-15T11:36:59Z

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