Fix some out-of-line constant pool garbage collection bugs.

Fix some out-of-line constant pool garbage collection bugs.

This CL fixes some bugs in the out of line constant pool implementation when
constant pools are GCed.  Namely:
  - Push/Pop pp register in exit frames and VisitPointer on it to ensure it is
    updated if the ConstantPoolArray is moved by GC.
  - Mark pp as a SafePoint Register for optimized functions.
  - Ensure that StandardFrame::IterateExpressions also iterates over the
    constant pool pointer in the stackframe.
  - Fix calculation of last_ptr_offset in ConstantPoolArray body iterator.
  - Make ensure that CONSTANT_POOL_ARRAY_TYPE is a pointer object InstanceType.

R=ulan@chromium.org

Committed: https://code.google.com/p/v8/source/detail?r=18473

[rmcilroy, 2014-01-03 18:19:27]

Ulan, please review this CL.

[ulan, 2014-01-07 08:32:03]

LGTM, good catches!

https://codereview.chromium.org/123263005/diff/30001/src/arm/lithium-codegen-...
File src/arm/lithium-codegen-arm.cc (right):

https://codereview.chromium.org/123263005/diff/30001/src/arm/lithium-codegen-...
src/arm/lithium-codegen-arm.cc:983: // Register pp always contains a pointer to
the context.
Register pp always contains a pointer to the constant pool?

[rmcilroy, 2014-01-07 14:57:29]

Thanks Ulan!

https://codereview.chromium.org/123263005/diff/30001/src/arm/lithium-codegen-...
File src/arm/lithium-codegen-arm.cc (right):

https://codereview.chromium.org/123263005/diff/30001/src/arm/lithium-codegen-...
src/arm/lithium-codegen-arm.cc:983: // Register pp always contains a pointer to
the context.
On 2014/01/07 08:32:03, ulan wrote:
> Register pp always contains a pointer to the constant pool?

Good catch :). Done.

[rmcilroy, 2014-01-07 15:54:07]

Committed patchset #4 manually as r18473 (presubmit successful).