Use vcs to sim systemc file

My ubuntu is 10.04, the default g++ is 4.4. But for simulating systemc file, you need to specify the lower version of g++.

The problem can be solved as follows:
1.  Go to the archive link to download the following five files:
    gcc-3.4-base_3.4.6-6Ubuntu3_i386.deb、
    gcc-3.4_3.4.6-6Ubuntu3_i386.deb、
    cpp-3.4_3.4.6-6Ubuntu3_i386.deb、
    g++-3.4_3.4.6-6Ubuntu3_i386.deb、
    libstdc++6-dev_3.4.6-6Ubuntu3_i386.deb
Put them into the same folder, like g++-3.4, and then run command "dpkg -i *.deb";

2. redirect the g++ link to use the lower version
   You can find the g++-3.4 with find / -name g++-3.4* command, however, it is already inside the /usr/bin if you are familiar. All you need to do right now is to redirect the g++ to your newly installed file.
   The command is "ln -sf /usr/bin/g++-3.4 /usr/bin/g++";
   There is also another way, check the reference link(in Chinese)

With the user guide, the easiest way is to run simulations of your systemc file is :
   syscan adder.cpp
   syscan adder_tb.cpp adder_main.cpp
   vcs -sysc sc_main
   ./simv

llvm patched with systemc library

By Rui Chen

In this article, I will get into the IR generated by the llvm-g++ along with the systemc library.

Understand the installation flow of PinaVM
The project is to mimic the idea of PinaVM, but I have to repeat the first few steps to understand the relationship between llvm-g++ and systemc library. Check out the /doc/install document for details.

One limit is that you have to use LLVM 2.6, which may suffer incompatible features with the latest version.

Start from autoconf part, which is Step 3 in the manual
1. autoconf
What the autoconf do is to seek a file named configure.ac (or configure.in for backward compatibility), and then runs the M4 macro processor to create the configure script.

2. configrue
command ./configure --with-tools-dir=$DOWNLOAD
Part of the output:

configure: Summary of variables:

DOWNLOAD_AND_COMPILE_DIR: /home/chenrui/Desktop/pinavm/download
INSTALL_PATH_LLVM: /home/chenrui/Desktop/pinavm/lib/llvm-2.7
INSTALL_PATH_LLVMGCC: /home/chenrui/Desktop/pinavm/lib/llvm-gcc
INSTALL_PATH_SYSTEMC_LLVM: /home/chenrui/Desktop/pinavm/lib/systemc-2.2.0-llvm
INSTALL_PATH_SYSTEMC_GCC: /home/chenrui/Desktop/pinavm/lib/systemc-2.2.0-gcc

configure: creating ./config.status
config.status: creating config.mk
config.status: creating config.sh

The code in the configure.ac file:

DOWNLOAD_AND_COMPILE_DIR="${TOOLS_DIR}/download"
INSTALL_PATH_LLVM=${TOOLS_DIR}/lib/llvm-2.7
INSTALL_PATH_LLVMGCC=${TOOLS_DIR}/lib/llvm-gcc
INSTALL_PATH_SYSTEMC_LLVM=${TOOLS_DIR}/lib/systemc-2.2.0-llvm
INSTALL_PATH_SYSTEMC_GCC=${TOOLS_DIR}/lib/systemc-2.2.0-gcc

So the "--with-tools-dir" means specifying the $DOWNLOAD directory for ${TOOLS_DIR}.

Another part of configure.ac:

# Defining files to be generated
AC_CONFIG_FILES([config.mk
                 config.sh])

Then config.mk and config.sh will be generated.
NOTE: normally, AC_CONFIG_FILES([Makefile]) is used(ref link).

Motivation to use SystemC and LLVM
I have done a simple literal translator with SystemC-to-VHDL translator with ANTLR, and I think it needs tremendous effort to crack the whole C++ grammar.
Besides, sc2v and gsc and many tools are based on their self-made compilers, which suffers a severe issue that only a small set of systemc grammar can be compiled.

Based on this understanding, it is very important to immigrate the translation method from ANTLR literal way to llvm-g++ based.


Generate simple backend first.
Another idea about working with C++ & Systemc with LLVM is that I can generate a VHDL experiment backend for test first and then connect it to the systemc frontend.

enum的翻译

By Rui Chen

VHDL 与systemc在enum的定义上有很大的不同。

VHDL-ref
Important Notes

• It is illegal to define an enumeration type with a range.
• It is assumed that the values are defined in ascending order. For this reason it is recommended to order the literals in such a way that the default value is the first one (it is referred to through the attribute 'left').
• Objects of enumeration types are typically synthesizeable.

所以，VHDL的