When we've discussed the v8 pointer/type situation before, it seemed like there would need to be some discussion on typedefs and style so that the types could really make sense internally for V8. It's hard, because there are pointers, pointers get tagged, they have certain bits used, and a lot of arithmetic can happen on them. The GC code will only work for 32-bits. All of the object tagging is designed only for 32-bits.
Making V8 work on 64-bits is much much bigger than changing some types around and changing the scons. It probably deserves some fairly big design discussions, and I would guess it would take at least a few months, and it will be hard not to fracture the code a bunch, with separate code for 32/64 bit (GC, object layout, etc). On Thu, Jan 22, 2009 at 4:21 PM, Jeff Bailey <[email protected]> wrote: > > Thanks! > > On x86_64 without -m32, this becomes a problem (as it would on ia64, > alpha, or other Debian architectures I might wind up porting this > to). I've heard from others that 64 bit targets aren't really > interesting to the V8 team, so I assume I'll keep keeping some fixes > out of tree for now, but in cases where I can push patches in upstream > that won't get in the way, I'd like to. > > I have a patch in my tree to make doing this build easy while still > letting me test the 32bit build. Debian and Ubuntu have a tool called > 'linux32' which will have the system report that it's running on ia32 > rather than x86_64. With the following patch, using "linux32 scons" > on amd64 produces the build the way you guys are used to and "scons" > attempts to build it for x86_64. Note that I haven't tested this on > arm as I don't have that environment setup. I don't remember off hand > if arm-linux-gcc accepts -m32. If not, I would need to tweak this > further. I also think the hack to tools/utils.py is probably wrong. > platform.machine() seems to always return the value we want, except > for i[3-7]86 where we want ia32. I suspect it should just test for > that and otherwise return whatever was handed to it. Distros and > whatnot would usually expect to use linux32 and a 32bit chroot to do > ia32 builds. > > Patch follows: > > Index: tools/utils.py > =================================================================== > --- tools/utils.py (revision 1129) > +++ tools/utils.py (working copy) > @@ -63,6 +63,8 @@ > id = platform.machine() > if id.startswith('arm'): > return 'arm' > + if id.startswith('x86_64'): > + return 'x86_64' > elif (not id) or (not re.match('(x|i[3-6])86', id) is None): > return 'ia32' > else: > Index: SConstruct > =================================================================== > --- SConstruct (revision 1129) > +++ SConstruct (working copy) > @@ -57,10 +57,10 @@ > 'os:freebsd': { > 'LIBS': ['execinfo'] > }, > - 'wordsize:64': { > + 'wordsize:32': { > 'CCFLAGS': ['-m32'], > 'LINKFLAGS': ['-m32'] > - } > + }, > }, > 'msvc': { > 'all': { > @@ -175,7 +175,7 @@ > 'all': { > 'LIBPATH': [abspath('.')] > }, > - 'wordsize:64': { > + 'wordsize:32': { > 'CCFLAGS': ['-m32'], > 'LINKFLAGS': ['-m32'] > }, > @@ -204,7 +204,7 @@ > 'os:freebsd': { > 'LIBS': ['execinfo'] > }, > - 'wordsize:64': { > + 'wordsize:32': { > 'CCFLAGS': ['-m32'], > 'LINKFLAGS': ['-m32'] > }, > @@ -298,7 +298,7 @@ > 'help': 'the os to build for' > }, > 'arch': { > - 'values':['arm', 'ia32'], > + 'values':['arm', 'ia32', 'x86_64'], > 'default': ARCH_GUESS, > 'help': 'the architecture to build for' > }, > > > On Jan 22, 9:03 am, Mads Sig Ager <[email protected]> wrote: >> Thanks for the patch! Using %p is the right thing here. It has been >> committed in V8 bleeding_edge revision 1128. :-) >> >> Do you have a build setup where this is a problem? If you do, we >> would be interested in more details of the setup so we can test >> against it. >> >> Cheers, -- Mads >> >> On Wed, Jan 21, 2009 at 7:10 PM, Jeff Bailey <[email protected]> wrote: >> >> > Hi! There seem to be a number of places that assume that a pointer is >> > the same size as an int (or an ILP32 system in general). Will fixes >> > like this be accepted? >> >> > 2009-01-20 Jeff Bailey <[email protected]> >> >> > * src/checks.h: Use %p modifier for displaying pointers. >> >> > Index: src/checks.h >> > =================================================================== >> > --- src/checks.h (revision 1112) >> > +++ src/checks.h (working copy) >> > @@ -136,9 +136,9 @@ >> > void* value) { >> > if (expected != value) { >> > V8_Fatal(file, line, >> > - "CHECK_EQ(%s, %s) failed\n# Expected: %i\n# Found: >> > %i", >> > + "CHECK_EQ(%s, %s) failed\n# Expected: %p\n# Found: >> > %p", >> > expected_source, value_source, >> > - reinterpret_cast<int>(expected), reinterpret_cast<int> >> > (value)); >> > + expected, value); >> > } >> > } >> >> > @@ -150,8 +150,8 @@ >> > const char* value_source, >> > void* value) { >> > if (expected == value) { >> > - V8_Fatal(file, line, "CHECK_NE(%s, %s) failed\n# Value: %i", >> > - expected_source, value_source, reinterpret_cast<int> >> > (value)); >> > + V8_Fatal(file, line, "CHECK_NE(%s, %s) failed\n# Value: %p", >> > + expected_source, value_source, value); >> > } >> > } > > > --~--~---------~--~----~------------~-------~--~----~ v8-dev mailing list [email protected] http://groups.google.com/group/v8-dev -~----------~----~----~----~------~----~------~--~---
