gcc960 Compiler Driver

gcc960 is a driver program that manages invocation of the preprocessor, compiler proper, assembler and linker. The invocation syntax is:

gcc960 { - | / } [-option ] ... file ...

Each invocation option must be preceded by a - character. (On DOS, you can also use a / character.) Click on option for information on compiler driver options. All options that take an argument allow optional white space between the option and the argument. When conflicting options are given, the last one specified is used. The compiler driver passes the following linker options and their arguments to the linker: e, gcdm, L, l, r, s, u, X, x, y and z.

The compilation system determines each input file's type by its filename extension:

The compilation system passes any other filename to the linker, which determines whether the file is an object file, library or configuration file by its contents.

Other invocation command elements are taken to be either linker options or object modules, typically produced by an earlier gcc960 invocation, or perhaps libraries of compatible routines. These modules, together with the result of any compilations specified, are linked (in the order given) to produce an executable program.

When generating b.out modules, the default output filename is b.out. When generating COFF modules, the default output filename is a.out. When generating ELF/DWARF modules, the default filename is e.out.

gcc960 Driver Options

Each option requires an option delimiter (- or /). When conflicting options are given, the last one specified is used. For information about an option, click on the option name (underlined).

A { CA | CF | HA | HD | HT | JA | JD | JF | KA | KB | RP | SA | SB }

(Architecture)

Compile code for a particular model of the i960 processor. If the environment variable G960ARCH is set and non-empty, its value is the default architecture. Otherwise the default is KB.

ansi (ANSI)

Flag non-standard (that is, non-ANSI) constructs. Using ansi disables inline assembly language statements and can override the w (No Warnings) option. This option causes the preprocessor macro __STRICT_ANSI to be defined.

C (Keep Comments)

Keep comments in preprocessor output. Works only with E.

c (Create Object)

Terminate the compilation process after the assembler generates an object file. If you do not specify the o (Output) option, the compiler writes the object file to filename.o, where filename is the source filename.

clist arg... (Listing)

Create a listing file with the suffix .L for each C source file. arg is a string containing one or more of the following letters:

crt (Startup)

Do not use the standard startup file.

Dsymbol[=value] (Define)

Define a macro with a given value. If =value is omitted, symbol is defined to be 1.

darg (Definitions)

Control macro processing.

E (Preprocess)

After the link phase of the compilation process is complete, produce an executable file.

Fbout | Fcoff | Felf (OMF)

Generate b.out, COFF or ELF objects. Fbout is the default.

fdb (Program Database)

All modules subject to program-wide optimization must be initially compiled with the fdb option. This option causes the insertion of program database information in the object modules, and it implies a minimum module-local optimization level of O1 (although higher module-local optimization levels are allowed).

This option does not otherwise change the code or data generated for the object modules in any way; it simply makes available to the global decision making and optimization process information collected during initial compilation of the modules.

Before using the fdb option, you should read Chapter 4, Program-Wide Analysis and Optimization, and Chapter 6, gcdm Decision Maker Option, in the i960 Processor Compiler User's Guide.

If you intend to use execution profiles when optimizing your application, you should read Chapter 5, Profile Data Merging and Data Format, in the i960 Processor Compiler User's Guide.

fprof (Instrument)

This option inserts execution profile instrumentation code into the module(s) during compilation, so that when the linked program is executed, a profile can be collected.

It also implies fdb, which causes the insertion of program database information in the object modules, and it implies a minimum module-local optimization level of O1.

When you compile with the fprof option, a special profiling library required for profile collection (libqf) is linked automatically. If your target environment does not support file I/O, you must explicitly link an alternate profiling library (libq). The profiling libraries provided are identified in Chapter 2 of the i960 Processor Library Supplement.

Note that when the fprof compiler option is used in this manner (as distinct from the corresponding +fprof gcdm960 Decision Maker option) the generated object module contains code that is unsuitable for linking into programs which are not supposed to collect profile information. To solve this problem, and avoid having inappropriate instrumentation in widely used libraries, for example, use +fprof with the gcdm,subst option.

Before using the fprof option, you should read Chapter 4, Program-Wide Analysis and Optimization, and Chapter 5, Profile Data Merging and Data Format, in the i960 Processor Compiler User's Guide.

f[no-]arg (Enable/Disable Optimization)

Enable/disable optimization. arg is one of:

asm
treat asm, inline, and typeof as keywords.
bbr
enable basic block rearrangement.
coalesce
coalesce adjacent memory references.
coerce
enable byte/short optimization.
cond-mismatch
allow type mismatch in operands of the ?: operator.
condxform
enable 80960 conditional instructions.
constprop
enable constant propagation and folding.
copyprop
enable copy propagation.
cse-follow-jumps
enable a limited form of global CSE.
cse-skip-blocks
enable a limited form of global CSE.
expensive-optimizations
enable some minor optimizations.
float-store
store floating-point variables in registers, and perform CSE on floating-point expressions.
force-addr
place address constants in registers before use.
inline-functions
inline all simple functions into their callers.
int-alias-ptr
indicates to the compiler that pointer objects may be referenced as 32-bit integers and vice versa.
int-alias-real
indicates to the compiler that float, double and long double objects (or parts thereof) may be referenced as 32-bit integers and vice versa.
int-alias-short
indicates to the compiler that four-byte integer objects may be referenced as two-byte objects and vice versa.
keep-inline-functions
emit out-of-line code for inlined functions.
marry_mem
rejoin multi-word moves split by fsplit_mem.
rerun-cse-after-loop
reiterate CSE after loop optimization.
sblock
enable superblock formation.
schedule-insns2
perform post-register-allocation scheduling.
shadow-globals
shadow memory locations in registers.
shadow-mem
like shadow-globals, but more thorough.
signed-char
make type char be signed (or unsigned).
space-opt
optimize for memory space.
split_mem
split multi-word moves for copy propagation.
strength-reduce
enable loop strength reduction.
thread-jumps
enable an advanced branch optimization.
unroll-all-loops
unroll all loops.
unroll-loops
unroll loops where deemed beneficial.
unsigned-char
make type char be unsigned (or signed).
verbose-asm
emit explanatory assembly language comments.
volatile
treat indirect memory references as volatile.
volatile-global
treat all memory references as volatile.
writable-strings
place string literals in .data section.

G (Big-endian)
Causes compiler to generate big-endian module(s).

g[level] (Debug)

Put symbolic debug information into the object module. level is:

gcdm,arg[,arg]... (Decision Maker)

Invoke gcdm960 decision maker to perform optimization or related tasks. Click gcdm option for information on this option.

h (Help)

Print a summary of gcc960 driver options and exit without processing any files.

I dir (Searchinclude)

Add the directory dir to the search list for #include files.

I | I. (I-dash, I-dot)

Any directories specified with I options before the I- option are searched only for #include "file"; they are not searched for #include <file>.

If additional directories are specified with I options after the I-, these directories are searched for all #include directives. (Ordinarily all I directories are searched this way.)

The I- option inhibits the use of the current directory as the first search directory for #include "file". The current directory is searched for #include "file" only if it is requested explicitly with I. (I "dot"). It is not searched automatically with I-. Specifying both I- and I. allows you to control precisely which directories are searched before the current one and which are searched after.

ic960 (iC-960)

Accept iC-960 R3.0 source dialect. For code compatibility, also use mic3.0-compat.

imacros filename (Macros File)

Specify macros file for preinclusion. Process file as input, discarding the resulting output, before processing the regular input file. Because the output generated from file is discarded, the only effect of imacros file is to make the macros defined in file available for use in the main input. Any D and U options on the command line are always processed before imacros file, regardless of the order in which they are written. All the include and imacros options are processed in the order in which they are written. All imacros options are processed before all include options.

include filename (Preinclude)

Include the specified source file as if a #include of that file existed at line zero of each primary source file. In effect, the contents of file are compiled first. Any D and U options on the command line are always processed before include file, regardless of the order in which they are written. All the include and imacros options are processed in the order in which they are written. All imacros options are processed before all include options.

jnum (Errata)

Use the j (Errata) option to cause the compilation system to generate code with workarounds for specified processor errata. A num argument of 1 generates code to work around the Cx processors' DMA errata.

L directory (Library Directory)

Specify directory for library search.

llibrary (Library)

Specify library for linking.

M | MD | MM | MMD (Make)

Generate make tool information.

M
Tells the preprocessor to output a rule suitable for a make tool describing the dependencies of each source file. For each source file, the preprocessor outputs one make rule whose target is the object file name for that source file and whose dependencies are all the files #included in it. This rule can be a single line or can be continued with \newline if it is long. Using this option stops compilation after preprocessing.
MD
Like M but the dependency information is written to files with names made by replacing .c with .d at the end of the input file names. This is in addition to compiling the file as specified; MD does not inhibit ordinary compilation the way M does.
MM
Like M, but the output mentions only the user-header files included with #include "file". System header files included with #include <file> are omitted.
MMD
Like MD except mention only user header files, not system header files.

mstring (Machine)

Enables various machine-specific options.

mabi
Generate 80960 ABI-conformant code.
masm-compat
Generate special Intel pseudo-operations for long compare-and-branch operations. gas960 or gas960c do not require these pseudo-ops in order to generate correct code, but the ASM960 R3.5 or earlier assembler will generate out-of-range errors for these instructions if this option is not used. This should not be used if gas960, gas960c, or gas960e are used, because the split compare-and-branch instructions are slower and larger than the combined ones.
mcave
Generate all functions as CAVE secondary.
mcmpbr | mno-cmpbr
Generate code that uses compare-and-branch instructions whenever possible, or that has no compare-and-branch instructions.
mcode-align | mno-nocode-align
Generate (do not generate) alignment directives prior to labels that are not entered from above. mcode-align is the default if the Cx or Hx architecture is specified.
mdouble4
Generate code so that the size and alignment of double is the same as float.
mlong-double4
Generate code so that the size and alignment of long double is the same as float.
mi960_align=n
Aligns struct data on the byte boundary which is a multiple of n.
mic-compat | mic2.0-compat
Use ic960 R2.0's rules for size and alignment of types. This option also causes the compiler to use ic960's rules for promotion of char, unsigned char, short, and unsigned short types at function call and return.
mic3.0-compat
Use ic960 R3.0's rules for size and alignment of types and other conventions. These are largely the same as gcc960's, but ic960 R3.0 selects the size of enums based on their value, and gcc960 emulates this. Additionally, ic960 R3.0 assumes that type char is signed by default, whereas gcc960 assumes it is unsigned. The mic3.0-compat option emulates ic960's behavior.
mleaf-procedures | mno-leaf-procedures
Generate output which contains (does not contain) leaf procedures: these are procedures that may be entered with the bal instruction rather than call. The linker automatically promotes call instructions into bal instructions when appropriate. This option makes debugging more difficult. mleaf-procedures is the default at O2 or higher.
mlong-calls
Generate all call instructions as calljx instead of callj. This is used where the distance between the call site and the called function exceeds callj's range. Using this option degrades code execution speed and increases code size.
mpic
Generate position-independent references to any objects in the text section. Such objects are functions, const file-scope variables, switch tables, and strings. Position independent code references are made relative to the current instruction pointer (IP).
mpid
Generate position-independent references to objects in the bss, common, and data sections. Such objects are non-const file-scope variables, and strings if the fwritable-strings option is used. Position independent code references are made relative to register g12. Register g12 is not used for any other purpose.
mpid-safe
Reserve register g12 as the position independent data bias register, but do not generate code for position independent data.
msoft-float
Generates output containing library calls for architectures without on-chip floating point support (all except KB, SB). This is set automatically, based on the architecture option.
mstrict-align | mno-strict-align
This option determines whether or not the compiler will risk generating memory references which are not provably aligned. If mstrict-align is disabled, the compiler will occasionally generate potentially unaligned references when it seems advantageous to do so. When mstrict-align is enabled, sequences of smaller memory references are used instead of larger ones which might not be correctly aligned. The default is on for C-series and J-series processors.
mstrict-ref-def
Generate code so that an uninitialized file-scope variable definition causes space to be allocated in the .bss section instead of as a .comm symbol. This enforces a single unique definition of a variable.
mtail-call | mno-tail-call
Generate output which converts (does not convert) call instructions immediately followed by ret instructions to branches to the call target. While generating faster code, this option makes debugging more difficult. mtail-call is the default at O2 or higher.
mwait=n
Specifies the expected number of wait-states for the memory being used in the target. This can make a difference in which optimizations are cost effective and in the instruction scheduling optimization. n must be in the range 0..32.

nostdinc (No Standard Includes)

Excludes standard header (include) files. Only the directories specified with I options (and the current directory, if appropriate) are searched. Using nostdinc and I-, you can eliminate all directories from the search path except those you specify.

nostdlib (No Standard Libraries)

Excludes standard libraries.

O[level] (Optimize)

Specify the optimization level to be used. Supported levels are 0, 1, 2, 3 and 4.

The O[level] option specifies the level of optimization as described below.

O0
Turns optimization off, and additionally disables default optimizations that may interfere with debugging. This is the default.
O[1]
This option turns on basic optimizations, including: advanced register allocation, common subexpression elimination, loop invariant code motion, expression simplification and instruction combination, jump optimization, dead-code elimination, and i960 processor-specific peephole optimization. O1 is equivalent to O. This is the default setting when you use the fdb (Program Database) or fprof (Instrument) option.
O2
This level includes the O[1] optimizations described above, and the following additional optimizations:
fcopyprop, fcondxform, fcse-follow-jumps, fcse-skip-blocks, fexpensive-optimizations, frerun-cse-after-loop, fschedule-insns, fschedule-insns2, fshadow-globals, fstrength-reduce.
The O2 level enables strength-reduction, combination of more than one variable value into a single register, copy propagation, and instruction reordering (scheduling) to make use of the particular i960 processor's pipeline and superscalar capabilities.
O3
This level includes the O2 optimizations described above, and the following additional optimizations:
fcoerce, fconstprop, finline-functions, fshadow-mem, funroll-loops.
O4
This level includes the O3 optimizations described above, and the following additional optimizations:
fcoalesce, fmarry_mem, fsplit_mem.

o filename (Output)

Names the output file, which can be either preprocessing output, assembly code, an object module, or linker output.

outz filename (Listname)

Directs the listing to the named file. This option implies the clist (List) option and s argument.

P (Preprocessor Output)

Inhibits generation of #-lines with line-number information in the output of the preprocessor.

pedantic[-errors] (Pedantic)

Controls ANSI message generation.

pedantic causes the compilation system to issue all the warnings specified by ANSI C (such as when text other than a comment follows #else or #endif) and to reject programs that use forbidden extensions.

Valid ANSI standard C programs should compile properly with or without this option (though a rare few will require ansi). However, without this option, certain GNU extensions and traditional C features are supported as well. With this option, they are rejected.

pedantic does not cause warning messages for use of the alternate keywords whose names begin and end with _ _ (double underscore).

pedantic-errors is the same as pedantic, except that it causes the compilation system to issue errors instead of warnings.

Q (No Quiet)

Suppresses passing quiet to compiler phases.

S (Save Assembly)

After the link phase of the compilation process, the compiler produces an executable file. Assembly language output is not saved. If you do not specify a filename with the o (Output) option, the compiler writes the assembly language output to filename.s, where filename is the source filename without its extension.

save-temps (Save Intermediates)

Store the usual "temporary" intermediate files permanently; place them in the current directory and name them based on the source file. Thus, compiling foo.c with -c -save-temps would produce files foo.i and foo.s, as well as foo.o.

Tfile[.gld] (Target)

Specifies a configuration file, which causes the compilation system to configure itself for a particular target board.

traditional (Traditional)

Allow some aspects of traditional C, as summarized below.

See the discussion of traditional in your compiler manual for a list of the macros defined when the traditional or ansi option is used.

trigraphs (Trigraphs)

Support ANSI trigraphs. (The ansi option also enables trigraphs.)

U symbol (Undefine)

Undefine a preprocessor symbol. By default, no symbols are undefined.

V (Version)

Display a version message and other information. By default, the compiler does not display version information.

v960 (Version, terminate)

Display version and terminate.

v (Verbose)

Display the driver's invocation command, and the preprocessor, compiler, assembler, and linker phase invocations. By default, the driver does not display individual phase invocations.

W [[no-]arg] (Warnings)

Enables/disables warnings. With no arg, this option prints extra warning messages for certain events, including:

longjmp() warnings
Warn if a nonvolatile automatic variable might be changed by a call to longjmp(). These warnings are possible only in an optimizing compilation.
The compiler sees only the calls to setjmp(). It cannot know where longjmp() will be called; in fact a signal handler could call it at any point in the code. As a result, you may get a warning even when there is in fact no problem because longjmp() cannot actually be called at the place that would cause a problem.
return and return(value)
Warn if a function can return either with or without a value. (Falling off the end of the function body is considered returning with a value.)
null effect
Warn if an expression-statement contains no side effects.
no-op comparison
Warn if an unsigned value is compared against zero with < or <=.
between-ness comparison
Warn if a comparison like x<=y<=z is used; this is equivalent to {(x<=y ? 1 : 0) <=z}, which is a different interpretation from that of ordinary mathematical notation.
obsolete storage class specification
Warn if storage-class specifiers like static are not the first things in a declaration. According to the ANSI C standard, this usage is obsolescent.
partially bracketed initializer
Warn if an aggregate has a partly bracketed initializer.

W[no-]arg can be:

aggregate-return
Warn if any functions return structures or unions.
all
Enable several useful warnings, as indicated in the list below. Has no Wno-all form.
cast-align
Warn if a pointer cast may not have required alignment.
cast-qual
Warn if a pointer cast removes a type qualifier.
char-subscripts
Warn if an array subscript has type char. Enabled by Wall.
comment
Warn whenever /* occurs within a comment. Enabled by Wall.
conversion
Warn if a prototyped parameter causes a different conversion than if not prototyped.
error
Treat all warnings as errors.
format
Check types of printf family arguments at compile time. Enabled by Wall.
id-clash-n
Warn if two identifiers match in the first n characters. Has no [no-] form.
implicit
Warn if a function is used before being declared. Enabled by Wall.
missing-braces
Warn if an aggregate initializer is not fully braced.
missing-prototypes
Warn if a function is defined before it is prototyped. Enabled by Wall.
nested-externs
Warn if an extern declaration is seen within a function.
parentheses
Warn if parentheses are suggested around an expression. Enabled by Wall.
pointer-arith
Warn if the size of a function type or type void is used.
redundant-decls
Warn if an object is declared twice in the same scope.
return-type
Warn if any function implicitly returns int, and if a non-void function does not return a value. Enabled by Wall.
shadow
Warn if a local variable shadows another local variable.
strict-prototypes
Warn if a function is declared without a prototype.
switch
Warn if a switch statement on an enumeration type does not have a case for each enumerator. Enabled by Wall.
traditional
Warn about constructs that behave differently under traditional C and ANSI C.
trigraphs
Warn if any trigraphs are encountered. Enabled by Wall.
uninitialized
Warn if use of an uninitialized local variable is detected. Enabled by Wall.
unused
Warn about objects that are never used. Enabled by Wall.
write-strings
Warn if string constants are used in a writable context.

w (No Warnings)

Inhibits all warning messages.

Zdir (Specify PDB)

Specifies the name of a program database directory.

Linker Options

e
Defines program entry point.

gcdm
Invoke gcdm960 decision maker.

Ldir
Add the library dir to the linker's search list.

l lib
Add the library lib to the linker's list of input libraries.

r
Retain relocation information in output object file.

s
Strip line-number and symbol-table entries from linker COFF output file.

u
Introduce unresolved symbol.

X
Remove all symbols from output symbol table.

x
Remove local symbols from output symbol table.

y
Trace a symbol.

z
Suppress COFF time stamp in linker output file.

Go to the top of this page.

Return to the gcc960 Interface Index.