D Front End for GCC

D Front End for GCC - Release 0.24

Last update: August 22, 2007

Supported Systems

GCC 3.4.x, 4.0.x, 4.1.x
Linux (tested on Fedora Core 5 x86, x86_64, and PowerPC)
Mac OS X 10.3.9, 10.4.x
FreeBSD 6.x
Cygwin
MinGW
AIX (tested on 5.1)

Similar versions of the above systems should work and other Unix platforms may work. Although the compiler will probably work on most architectures, the D runtime library will still need to be updated to support them.

Requirements

The MacOS X universal binary package requires XCode 2.4.1 or the equivalent version of cctools.

Downloads

Contact

David Friedman
e-mail: dvdfrdmn <at> users.sf.net

Status

Known Issues

See the DStress page for known failing cases.
Debugging information may have a few problems. To enable D name mangling in gdb, apply this patch.
Some targets do not support once-only linking. A workaround is to manually control template emission. See the -femit-templates option below. For Darwin, Apple's GCC 3.x compiler supports one-only linking, but GDC does not build with those sources. There are no problems with the stock GCC 4.x on Darwin.

Complex floating point operations may not work the same as DMD.
Some math functions behave differently due to different implementations of the extended floating-point type.
Volatile statements may not always do the right thing.
Because of a problem on AIX, the linker will pull in more modules than needed.
Some C libraries (Cygwin, MinGW, AIX) don't handle floating-point formatting and parsing in a standard way.

Known Differences from DMD

The type of _argptr in variadic functions is the target-specific va_list type. The only portable way to use _argptr is the std.stdarg.va_arg template. In particular, you cannot construct a va_list from a pointer to data an expect it to work.
In assembler code, direct access to parameters in naked functions works differently. Frame relative addressing through [ESP+4] does work the same way.
Currently, GDC uses the C calling convention for all functions except those declared extern (Windows).
GDC allows catch statements in finally blocks.
pragma(lib) is not supported.
Some targets do not have a distinct extended floating-point type. On these targets, real and double are the same size.
On Win32, GDC allocates 12 bytes for the real type, while DMD allocates 10 bytes. This also applies to the components of the creal type.

Inline Assembler Notes

Getting GCC to respect the "naked" attribute is difficult. It is recommended that you use only assembler statements in a naked function. When generating position-independent code, accessing global symbols in a naked function will result in an error.
Jumps from assembler statements will not run cleanups (auto and finally)

Usage

Invoking gdc and gdmd

The compiler driver is named 'gdc' and accepts the standard GCC options. There is also a script named 'gdmd' which has the same interface as the Digital Mars dmd.

The mapping from DMD options to GCC is as follows:

-c	-c
-D	-fdoc
-Dd<docdir>	-fdoc-dir=<docdir>
-Df<filename>	-fdoc-file=<filename>
-d	-fdeprecated
-debug[=<arg>]	-fdebug[=<arg>]
-g	-g
-inline	-finline-functions
-I<path>	-I <path>
-J<path>	-J<path>
-L<arg>	-Wl,<arg>
-O	-O3 without inlining (may not be equivalent)
-o-	-fsyntax-only
-od<dir>	no equivalent; use the wrapper script
-of<file>	-o <file>
-op<dir>	no equivalent; use the wrapper script
-profile	(see the GCC manual for profiling options)
-quiet	no equivalent
-release	-frelease
-run	no equivalent; use the wrapper script
-unittest	-funittest
-version=<arg>	-fversion=<arg>
-w	-Wall
<.ddoc file>	-fdoc-inc=<.ddoc file>

Other options:

-f[no-]bounds-check	Controls array bounds checking
-femit-templates[=normal\|private\|all\|none\|auto] -f[no-]emit-templates	Controls whether or not template code is emitted. "normal" -- Emit templates, expecting multiple copies to be merged by the linker. "private" -- Emit templates, but make them private to the translation unit. The executable will have multiple copies of code and data. "all" -- Emit all template instances with public visibility. Do this even if they would not normally be emitted. "none" -- Do not emit templates at all. "auto" -- For targets that support templates, the "full" mode is used. Otherwise, the "private" mode is used. "none" and -fno-emit-templates are synonyms. "auto" and -femit-templates are synonyms.
-fall-sources	For each source file on the command line, semantically process each file preceding it. Use this if compilation errors occur due to complicated circular module references. This will slow compilation noticeably.
-fdump-source	Dump decoded UTF-8 text and source from HTML to <source>.utf-8 and <source>.d.utf-8.

Extensions

Extended Assembler

GDC implements a GCC extension that allows inline assembler with D expression operands. It is available on nearly all targets, not just i386. The syntax differs from the C language extension in the follow ways.

Statements start with 'asm { ...', just like the regular DMD inline assembler.
It is not necesary to put parentheses around operands.
Instruction templates can be compile-time string constants, not just string literals. If the template is not a string literal, use parenthesis to indicate that it is not an opcode.

Unlike i386 inline assembler statements, extended assembler statements do not prevent a function from being inlined.

See the GCC manual for more information about this extension.

Example:

uint invert(uint v)
{
    uint result;
    version(X86)
    asm{ "notl %[iov]" : [iov] "=r" result : "0" v; }
    else version(PPC)
    asm{ "nor %[oresult],%[iv],%[iv]" : [oresult] "=r" result : [iv] "r" v; }
    return result;
}

Declaration and Type Attributes

(This extension is a work in progress.)

GDC implements the GCC __attribute__ extension with two pragmas:

pragma(GNU_attribute, name1(arg1, arg2, ...), ...) declarations...

pragma(GNU_set_attribute, symbol, name1(arg1, arg2...), ...);

If an attribute has no arguments, the argument list may be omitted.

The first form applies to declarations directly contained in the pragma. The second form affects the given symbol. See the GCC manual for a list of attributes that can be set. Not all attributes are supported yet by GDC. Also, the interaction between these extended attributes and D languge attributes (alignment, for example) is not well defined.

Changes

0.24:

Removed support for GCC 3.3.x
Updated to DMD 1.020
Fixed Bugzilla 1037, 1038 (gdc specific), 1043, 1045, 1046,
Fixed SourceForge issues 1689634, 1749622, 1721496, 1721435

0.23:

Added support for 64-bit targets
Added multilib support
Updated to DMD 1.007
Fixed Bugzilla 984, 1013

0.22:

Added support for GCC 4.1.x
Support for GCC 3.3.x is deprecated
Updated to DMD 1.004
Fixed Bugzilla 836, 837, 838, 839, 841, 843, 844, 889, 896
Fixed problems with missing debug information
Added Rick Mann's -frameowrk patch for gdmd

0.21:

Updated to DMD 1.00
Fixed Bugzilla 695, 696, 737, 738, 739, 742, 743, 745
Implemented GCC extended assembler
Implemented basic support for GCC attributes

0.20:

Updated to DMD 0.177
Fixes for synchronized code generation
Better support for cross-hosted builds
Fixed Bugzilla 307, 375, 403, 575, 578
Applied Anders Björklund's MacOS X build patches

0.19:

Fixed D Bugzilla bugs 141(gdc), 157, 162, 164, 171, 174, 175, 192, 229
Applied Dave Fladebo's suggestion for -O3 in gdmd
Updated to DMD 0.162
The version symbol for FreeBSD is now "freebsd"
Enabled std.loader for FreeBSD
Implement offsetof in assembler
Support building with Apple's GCC (4.0 only)
Fix parallel builds

0.18:

Fixes

ICE on assignment arithmetic
Problems mixing D and assembler floating point operations
Mac OS X 10.2 build problems
The gdc driver no longer compiles C source as C++.
Many others...

Improvements

Updated to DMD 0.157.
Added support for PowerPC Linux.
Added partial support for SkyOS.
Compiler can be relocated to another directory.

0.17:

Fixes

Mixed complex/float operations on GCC 4.0 (D.gnu/1485)
Applied Thomas Kuhne's HTML line number fix
Foreach/nested functions in templates (D.gnu/1514)
Use correct default initializer when allocating arrays of typedef'd types
Recursive calls to nested functions (D.gnu/1525)

Improvements

Updated to DMD 0.140

0.16:

Fixes

Concatenating a array and single element
"__arrayArg already defined"
ICE on nested foreach statements (D.gnu/1393)
Inline assembler

Functions returning floating point types

Spurious error on scaled register without a base register
Access to locals by var+ofs[EBP] now works with optimization.
Can now guess operand size from referenced variables.

Thunks errors with reimplemented interfaces (e.g., Mango)

Improvements

Support GCC 4.0.x
Updated to DMD 0.137
Support DW_LANG_D for DWARF debugging
Support compiling multiple sources to a single object with GCC 3.4.x.

0.15:

Updated to DMD 0.128

0.14:

Fixes

Classes nested in functions actually work now.
Fix for newest versions of the GNU assembler.

Improvements

Updated to DMD 0.127

0.13:

Fixes

Cygwin/MinGW assembler problem

Improvements

Updated to DMD 0.126.
Calling nested functions with delegates is faster.
The "check-target-libphobos" uses unit tests and runtime checks.

0.12.1:

Fixes

Compilation errors and crashes with -fpic
Crashes with interfaces on Cygwin/MinGW
Support the -mno-cygwin option

0.12:

Fixes

Various problems building MinGW in MSYS
Mango "endless output"
Build problems with gcc 3.4.1
Various problems revealed by dmdscript
Error message now go to standard error
DStress catch_01, catch_02, new_04, switch_19, throw_02, and others.

Improvements

Updated to DMD 0.125
New target: AIX
GDC and DMD versions are reported with "gcc --version"
Take advantage of DMD template improvements on

Changes

std.c.unix is now std.c.unix.unix
The runtime library is now "libgphobos" to avoid conflicts with DMD.
The dmd wrapper script...

Is now named "gdmd".
Looks for gdc in its own directory instead of searching the path
Requires a comma after the "-q" option.

0.11:

Fixes

Reversed structure compare
Correct meaning of '-L' option in wrapper script
Static data GC bug on Linux

Improvements

Updated to DMD 0.121
New target: MingGW
Included Anders F Björklund's man pages.
It is now possible to build a cross-compiler. Only MingGW is supported out-of-the-box, however.

License

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA