gcc/doc/frontends.texi

   1 @c Copyright (C) 1988-2018 Free Software Foundation, Inc.
   2 @c This is part of the GCC manual.
   3 @c For copying conditions, see the file gcc.texi.
   4
   5 @node G++ and GCC
   6 @chapter Programming Languages Supported by GCC
   7
   8 @cindex GCC
   9 @cindex GNU Compiler Collection
  10 @cindex GNU C Compiler
  11 @cindex Ada
  12 @cindex Fortran
  13 @cindex Go
  14 @cindex Objective-C
  15 @cindex Objective-C++
  16 GCC stands for ``GNU Compiler Collection''.  GCC is an integrated
  17 distribution of compilers for several major programming languages.  These
  18 languages currently include C, C++, Objective-C, Objective-C++,
  19 Fortran, Ada, Go, and BRIG (HSAIL).
  20
  21 The abbreviation @dfn{GCC} has multiple meanings in common use.  The
  22 current official meaning is ``GNU Compiler Collection'', which refers
  23 generically to the complete suite of tools.  The name historically stood
  24 for ``GNU C Compiler'', and this usage is still common when the emphasis
  25 is on compiling C programs.  Finally, the name is also used when speaking
  26 of the @dfn{language-independent} component of GCC: code shared among the
  27 compilers for all supported languages.
  28
  29 The language-independent component of GCC includes the majority of the
  30 optimizers, as well as the ``back ends'' that generate machine code for
  31 various processors.
  32
  33 @cindex COBOL
  34 @cindex Mercury
  35 The part of a compiler that is specific to a particular language is
  36 called the ``front end''.  In addition to the front ends that are
  37 integrated components of GCC, there are several other front ends that
  38 are maintained separately.  These support languages such as
  39 Mercury, and COBOL@.  To use these, they must be built together with
  40 GCC proper.
  41
  42 @cindex C++
  43 @cindex G++
  44 @cindex Ada
  45 @cindex GNAT
  46 Most of the compilers for languages other than C have their own names.
  47 The C++ compiler is G++, the Ada compiler is GNAT, and so on.  When we
  48 talk about compiling one of those languages, we might refer to that
  49 compiler by its own name, or as GCC@.  Either is correct.
  50
  51 @cindex compiler compared to C++ preprocessor
  52 @cindex intermediate C version, nonexistent
  53 @cindex C intermediate output, nonexistent
  54 Historically, compilers for many languages, including C++ and Fortran,
  55 have been implemented as ``preprocessors'' which emit another high
  56 level language such as C@.  None of the compilers included in GCC are
  57 implemented this way; they all generate machine code directly.  This
  58 sort of preprocessor should not be confused with the @dfn{C
  59 preprocessor}, which is an integral feature of the C, C++, Objective-C
  60 and Objective-C++ languages.