NAME

       gccgo - A GCC-based compiler for the Go language

SYNOPSIS

       gccgo [-c|-S]
             [-g] [-pg] [-Olevel]
             [-Idir...] [-Ldir...]
             [-o outfile] infile...

       Only the most useful options are listed here; see below for the remainder.

DESCRIPTION

       The gccgo command is a frontend to gcc and supports many of the same options.    This
       manual only documents the options specific to gccgo.

       The gccgo command may be used to compile Go source code into an object file, link a
       collection of object files together, or do both in sequence.

       Go source code is compiled as packages.  A package consists of one or more Go source
       files.  All the files in a single package must be compiled together, by passing all the
       files as arguments to gccgo.  A single invocation of gccgo may only compile a single
       package.

       One Go package may "import" a different Go package.  The imported package must have
       already been compiled; gccgo will read the import data directly from the compiled package.
       When this package is later linked, the compiled form of the package must be included in
       the link command.

       Go programs must generally be compiled with debugging information, and -g1 is the default
       as described below.  Stripping a Go program will generally cause it to misbehave or fail.

OPTIONS

       -Idir
           Specify a directory to use when searching for an import package at compile time.

       -Ldir
           When linking, specify a library search directory, as with gcc.

       -fgo-pkgpath=string
           Set the package path to use.  This sets the value returned by the PkgPath method of
           reflect.Type objects.  It is also used for the names of globally visible symbols.  The
           argument to this option should normally be the string that will be used to import this
           package after it has been installed; in other words, a pathname within the directories
           specified by the -I option.

       -fgo-prefix=string
           An alternative to -fgo-pkgpath.  The argument will be combined with the package name
           from the source file to produce the package path.  If -fgo-pkgpath is used,
           -fgo-prefix will be ignored.

           Go permits a single program to include more than one package with the same name in the
           "package" clause in the source file, though obviously the two packages must be
           imported using different pathnames.  In order for this to work with gccgo, either
           -fgo-pkgpath or -fgo-prefix must be specified when compiling a package.

           Using either -fgo-pkgpath or -fgo-prefix disables the special treatment of the "main"
           package and permits that package to be imported like any other.

       -fgo-relative-import-path=dir
           A relative import is an import that starts with ./ or ../.  If this option is used,
           gccgo will use dir as a prefix for the relative import when searching for it.

       -frequire-return-statement
       -fno-require-return-statement
           By default gccgo will warn about functions which have one or more return parameters
           but lack an explicit "return" statement.  This warning may be disabled using
           -fno-require-return-statement.

       -fgo-check-divide-zero
           Add explicit checks for division by zero.  In Go a division (or modulos) by zero
           causes a panic.  On Unix systems this is detected in the runtime by catching the
           "SIGFPE" signal.  Some processors, such as PowerPC, do not generate a SIGFPE on
           division by zero.  Some runtimes do not generate a signal that can be caught.  On
           those systems, this option may be used.  Or the checks may be removed via
           -fno-go-check-divide-zero.  This option is currently on by default, but in the future
           may be off by default on systems that do not require it.

       -fgo-check-divide-overflow
           Add explicit checks for division overflow.  For example, division overflow occurs when
           computing "INT_MIN / -1".  In Go this should be wrapped, to produce "INT_MIN".  Some
           processors, such as x86, generate a trap on division overflow.  On those systems, this
           option may be used.  Or the checks may be removed via -fno-go-check-divide-overflow.
           This option is currently on by default, but in the future may be off by default on
           systems that do not require it.

       -fno-go-optimize-allocs
           Disable escape analysis, which tries to allocate objects on the stack rather than the
           heap.

       -fgo-debug-escapen
           Output escape analysis debugging information.  Larger values of n generate more
           information.

       -fgo-debug-escape-hash=n
           A hash value to debug escape analysis.  n is a binary string.  This runs escape
           analysis only on functions whose names hash to values that match the given suffix n.
           This can be used to binary search across functions to uncover escape analysis bugs.

       -fgo-debug-optimization
           Output optimization diagnostics.

       -fgo-c-header=file
           Write top-level named Go struct definitions to file as C code.  This is used when
           compiling the runtime package.

       -fgo-compiling-runtime
           Apply special rules for compiling the runtime package.  Implicit memory allocation is
           forbidden.  Some additional compiler directives are supported.

       -fgo-embedcfg=file
           Identify a JSON file used to map patterns used with special "//go:embed" comments to
           the files named by the patterns.  The JSON file should have two components: "Patterns"
           maps each pattern to a list of file names, and "Files" maps each file name to a full
           path to the file.  This option is intended for use by the go command to implement
           "//go:embed".

       -g  This is the standard gcc option.  It is mentioned here because by default gccgo turns
           on debugging information generation with the equivalent of the standard option -g1.
           This is because Go programs require debugging information to be available in order to
           get backtrace information.  An explicit -g0 may be used to disable the generation of
           debugging information, in which case certain standard library functions, such as
           "runtime.Callers", will not operate correctly.

SEE ALSO

       gpl(7), gfdl(7), fsf-funding(7), gcc(1) and the Info entries for gccgo and gcc.

COPYRIGHT

       Copyright (c) 2010-2021 Free Software Foundation, Inc.

       Permission is granted to copy, distribute and/or modify this document under the terms of
       the GNU Free Documentation License, Version 1.3 or any later version published by the Free
       Software Foundation; with no Invariant Sections, the Front-Cover Texts being (a) (see
       below), and with the Back-Cover Texts being (b) (see below).  A copy of the license is
       included in the man page gfdl(7).

       (a) The FSF's Front-Cover Text is:

            A GNU Manual

       (b) The FSF's Back-Cover Text is:

            You have freedom to copy and modify this GNU Manual, like GNU
            software.  Copies published by the Free Software Foundation raise
            funds for GNU development.