Restructured build section. Created smaller files. Created (hidden) sub-ToCs. Added out-dated build instructions for Windows GNAT GPL flow from private README.md.

1 files changed, 92 insertions, 0 deletions

diff --git a/doc/building/gcc/index.rst b/doc/building/gcc/index.rst
new file mode 100644
index 000000000..73c9d1e97
--- /dev/null
+++ b/doc/building/gcc/index.rst
@@ -0,0 +1,92 @@
+.. _BUILD:gcc:
+
+GCC Backend
+###########
+
+.. rubric:: Requirements
+
+* GCC (Gnu Compiler Collection)
+* GNAT (Ada compiler for GCC)
+
+
+.. rubric:: Supported platforms
+
+* :ref:`GNU/Linux with GCC <BUILD:mcode:GNULinux-GCC>`
+* :ref:`Windows (x86_64) with GNAT GPL (x86) <BUILD:mcode:Windows-GNATGPL>`
+* :ref:`Windows (x86_64) with MinGW32/MinGW64 <BUILD:mcode:Windows-WinGW>`
+
+.. toctree::
+   :hidden:
+
+   GNULinux-GNAT
+   Windows-WinGW
+
+	 
+	 
+.. TODO::
+
+	- You need to download and untar the sources of GCC version 4.9.x, 5.x or 6.x
+	- gcc object dir
+	- Notes for developpers developping with the GCC backend: once GCC (with GHDL) has been built once, it is possible to work on the GHDL source tree without copying it in the GCC tree. Commands are::
+	
+		$ make ghdl1-gcc           # Build the compiler
+		$ make ghdl_gcc            # Build the driver
+		$ make libs.vhdl.local_gcc # Compile the vhdl libraries
+		$ make grt-all             # Build the GHDL runtime
+		$ make grt.links           # Locally install the GHDL runtime	
+
+GNU/Linux
+---------
+
+- First configure GHDL, specify GCC source dir and :samp:`prefix` (replace :samp:`/usr/local` with your desired installation directory)::
+
+	./configure --with-gcc=/path/to/gcc/source/dir --prefix=/usr/local
+	
+- Then, invoke :samp:`make` to copy GHDL sources in the source dir::
+
+	make copy-sources
+
+.. HINT:: There are some dependencies for building GCC (:samp:`gmp`, :samp:`mpfr` and :samp:`mpc`). If you have not them installed on your system, you can either build them manually or use the :samp:`download_prerequisite` script provided in the GCC source tree (recommended): :samp:`cd /path/to/gcc/source/dir && ./contrib/download_prerequisites`
+
+- Then, configure GCC. The list of :samp:`--disable` configure options can be adjusted to your needs. GHDL does not require all these optional libraries and disabling them will speed-up the build::
+
+	../gcc-4.9.3/configure --prefix=/usr/local --enable-languages=c,vhdl \
+	--disable-bootstrap --disable-lto --disable-multilib --disable-libssp \
+	--disable-libgomp --disable-libquadmath ``.
+
+.. HINT:: Note that the prefix directory must be the same as the one used to configure GHDL. If you have manually built :samp:`gmp`/:samp:`mpfr`/:samp:`mpc` (without using the script in :samp:`contrib`) and if you have installed them in a non-standard directory, you may need to add :samp:`--with-gmp=GMP_INSTALL_DIR`.
+
+- Then, build and install GCC::
+
+	make -j2 && make install
+
+.. HINT:: If you don't want to install :samp:`makeinfo`, do :samp:`make install MAKEINFO=false` instead.
+
+- Last, build and install GHDL libraries::
+
+	cd /path/to/ghdl/source/dir
+	make ghdllib
+	make install
+
+Windows?
+--------
+
+.. TODO:
+
+    Since the content of BUILD.txt is moved to the docs, what shall we do with this line? +gcc version 6.3 [do not modify this line as this is read by scripts].
+
+	Note for ppc64 (and AIX ?) platform: the object file format contains an identifier for the source language. Because gcc doesn't know about the VHDL, gcc crashes very early. This could be fixed with a very simple change in gcc/config/rs6000/rs6000.c, function rs6000_output_function_epilogue (as of gcc 4.8):
+	
+	.. CODE:: C
+	
+		else if (! strcmp (language_string, "GNU Objective-C"))
+			i = 14;
+		else
+		-  gcc_unreachable ();
+		+  i = 0;
+		fprintf (file, "%d,", i);
+
+       /* 8 single bit fields: global linkage (not set for C extern linkage,
+
+	Install file for the binary distribution of GHDL. The binary are installed in /usr/local directory.  You cannot change this default location, unless you set links. You must be root to install this distribution. To install ghdl: `tar -C / -jxvf @TARFILE@.tar.bz2`. Note: you must also have a C compiler and zlib installed.
+	 
\ No newline at end of file