User guide

3-3
Compiling and Elaborating Your Design
For a complete description of the syntax of the vcs command, see
Appendix B, "Compile-Time Options".
Incremental Compilation
VCS compiles your source code on a module-by-module basis. By
default, when you recompile the design, VCS recompiles only the
modules that have changed since the last compilation. This is called
incremental compilation.
During compilation VCS creates a subdirectory named csrc to store
the files generated by compilation. These files are as follows:
• A makefile that controls the compilation process.
• The object files output from compilation. VCS links these files with
the simulation engine to create the simv executable. If you use
native code generation (available only on Solaris, HP, and Linux),
VCS generates these files directly.
• Intermediate C or assembly files. If you are not using native code
generation, VCS by default compiles or assembles the object files
for the modules in your design.
In incremental compilation, when you enter a vcs command line,
VCS compares the modules in your source files to the descriptor
information in the generated files from the previous compilation. If a
module’s contents are different from what VCS recorded in the
descriptor information, VCS recompiles the module. If the module’s
contents match what is recorded in the descriptor information, VCS
does not recompile the module.