Add unit test for 64-bit assembler

Add a unit test for V8's 64-bit assembler.

Committed: http://code.google.com/p/v8/source/detail?r=2051

[Kevin Millikin (Chromium), 2009-05-22 13:20:54]

Change the commit message to say "Add unit test for the 64-bit assembler."

I'm concerned about multiplication of testing configurations.  Is it possible to
arch=x64 on Windows and Mac?  If so, does this test pass?

http://codereview.chromium.org/115707/diff/11/12
File test/cctest/test-assembler-x64.cc (right):

http://codereview.chromium.org/115707/diff/11/12#newcode47
Line 47: // convention is used on 64-bit windows.
What happens if the tests are run for arch=x64 on Windows or Mac?  Does it not
even get this far?

http://codereview.chromium.org/115707/diff/11/12#newcode57
Line 57: v8::internal::byte* buffer;
It seems easier to just use OS:Allocate here instead of virtual memory.

You don't have to write v8::internal:: here, do you?  I think it reads better to
use it everywhere or not use it at all, consistently.

[William Hesse, 2009-05-22 15:09:21]

Comments addressed.  Windows platform is currently not implemented.

http://codereview.chromium.org/115707/diff/11/12
File test/cctest/test-assembler-x64.cc (right):

http://codereview.chromium.org/115707/diff/11/12#newcode57
Line 57: v8::internal::byte* buffer;
On 2009/05/22 13:20:54, Kevin Millikin wrote:
> It seems easier to just use OS:Allocate here instead of virtual memory.
> 
> You don't have to write v8::internal:: here, do you?  I think it reads better
to
> use it everywhere or not use it at all, consistently.

Done.

[iposva, 2009-05-22 16:02:32]

http://codereview.chromium.org/115707/diff/18/1006
File test/cctest/test-assembler-x64.cc (right):

http://codereview.chromium.org/115707/diff/18/1006#newcode46
Line 46: // This calling convention is used on Linux, with GCC.  A different
Please check if the same calling convention is used on Mac OS with gcc and
update the comment.

[William Hesse, 2009-05-25 10:54:32]

http://codereview.chromium.org/115707/diff/18/1006
File test/cctest/test-assembler-x64.cc (right):

http://codereview.chromium.org/115707/diff/18/1006#newcode46
Line 46: // This calling convention is used on Linux, with GCC.  A different
On 2009/05/22 16:02:32, iposva wrote:
> Please check if the same calling convention is used on Mac OS with gcc and
> update the comment.

Done.  The Mac does use the same calling convention. Added.

[William Hesse, 2009-05-26 07:18:37]

I need an LGTM, or more comments to address.

[Lasse Reichstein, 2009-05-26 07:49:21]

LGTM

http://codereview.chromium.org/115707/diff/18/1006
File test/cctest/test-assembler-x64.cc (right):

http://codereview.chromium.org/115707/diff/18/1006#newcode43
Line 43: // The AMD64 calling convention is used, with the first five arguments
"first six arguments"

http://codereview.chromium.org/115707/diff/18/1006#newcode45
Line 45: // the XMM registers.  The return value is in RAX.
To be pedantic, if one of the first six arguments is a floating point value,
it's put in the XMM register, and the seventh argument ends up in R9.
I think it's safer to just say that we don't use floating point arguments,
exclamation point.

http://codereview.chromium.org/115707/diff/18/1006#newcode47
Line 47: // convention is used on 64-bit windows.
The MSVC calling convention uses RCX, RDX, R8 and R9 for arguments - meaning the
test below will not work there.
Add a TODO saying that until we fix on a way to specify parameters.

http://codereview.chromium.org/115707/diff/18/1006#newcode56
Line 56: TEST(AssemblerX640) {
X640 sounds large. Try giving it a more meaningful name than "0".

http://codereview.chromium.org/115707/diff/18/1006#newcode59
Line 59: byte* buffer =
static_cast<byte*>(OS::Allocate(Assembler::kMinimalBufferSize,
Don't use "minimal buffer size" here without asserting that it's large enough
for what you plan to do. 
It's better to use some arbitrary, but large enough, size, since the assembler
can't grow it anyway.
And test that the actual size is large enough too.