TASKING VX-toolset for ARM User Guide

Chapter 4. Using the C CompilerThis chapter describes the compilation process and explains how to call the C compiler.The TASKING VX-toolset for ARM under Eclipse can use the internal builder (default) or the TASKINGmakefile generator (external builder) to build your entire embedded project, from C source till the finalELF/DWARF object file which serves as input for the debugger.Although in Eclipse you cannot run the C compiler separately from the other tools, this section discussesthe options that you can specify for the C compiler.On the command line it is possible to call the C compiler separately from the other tools. However, it isrecommended to use the control program for command line invocations of the toolset (see Section 10.1,Control Program). With the control program it is possible to call the entire toolset with only one commandline.The C compiler takes the following files for input and output:This chapter first describes the compilation process which consists of a frontend and a backend part.Next it is described how to call the C compiler and how to use its options. An extensive list of all optionsand their descriptions is included in Section 12.2, C Compiler Options. Finally, a few important basic tasksare described, such as including the C startup code and performing various optimizations.4.1. Compilation ProcessDuring the compilation of a C program, the C compiler runs through a number of phases that are dividedinto two parts: frontend and backend.The backend part is not called for each C statement, but starts after a complete C module or set of moduleshas been processed by the frontend (in memory). This allows better optimization.The C compiler requires only one pass over the input file which results in relative fast compilation.Frontend phases1. The preprocessor phase:The preprocessor includes files and substitutes macros by C source. It uses only string manipulationson the C source. The syntax for the preprocessor is independent of the C syntax but is also describedin the ISO/IEC 9899:1999(E) standard.147