The motivation for this is that CompilationInfo really shouldn't
explicitly know anything about CodeStubs. This is evident in
the TurboFan stubs pipeline, which only needs to pass down
information about Code::Flags to the code generator and not
any of the CallInterfaceDescriptor silliness that Hydrogen has
to push around, since TF has the Linkage class that
encapsulates everything that is needed for the stub ABI. So,
instead of threading CodeStub machinery through the TF stub
pipeline, it is now removed from CompilationInfo and replaced
by only the explicit bits needed both by the Crankshaft and
TF pipelines in code generation.
Review URL: https://codereview.chromium.org/1604543002
Cr-Commit-Position: refs/heads/master@{#33410}
* Add a sibling interface to InterpreterAssembler called
CodeStubAssembler which provides a wrapper around the
RawMachineAssembler and is intented to make it easy to build
efficient cross-platform code stubs. Much of the implementation
of CodeStubAssembler is shamelessly stolen from the
InterpreterAssembler, and the idea is to eventually merge the
two interfaces somehow, probably moving the
InterpreterAssembler interface over to use the
CodeStubAssembler. Short-term, however, the two interfaces
shall remain decoupled to increase our velocity developing the
two systems in parallel.
* Implement the StringLength stub in TurboFan with the new
CodeStubAssembler. Replace and remove the old Hydrogen-stub
version.
* Remove a whole slew of machinery to support JavaScript-style
code stub generation, since it ultimately proved unwieldy,
brittle and baroque. This cleanup includes removing the shared
code stub context, several example stubs and a tangle of build
file changes.
BUG=v8:4587
LOG=n
Review URL: https://codereview.chromium.org/1475953002
Cr-Commit-Position: refs/heads/master@{#32508}
