Removes the new.target slot from the interpreter's fixed frame. Instead
adds a field to BytecodeArray to get the bytecode's incoming
new.target or generator object register. The InterpreterEntryTrampoline
then sets this register with the incoming new.target (or generator object)
when the function is called. This register can be directly the new.target
or generator object variable if they are LOCAL location, otherwise it is a
temporary register which is then moved to the variable's location during the
function prologue.

This fixes a hack in the deoptimizer where we would set the new.target fixed
slot to undefined in order to avoid extending it's lifetime through the
optimized code - now it's just a standard register and can be optimized away
as normal.

Bug=v8:6644

Change-Id: Ieb8cc34cccefd9fb6634a90cbc77c6002a54f2ae
Reviewed-on: https://chromium-review.googlesource.com/608966
Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47320}

Goal of this CL: explicit return from non-async function has position after
return expression as return position (will unblock [1]).

BytecodeArrayBuilder has SetStatementPosition and SetExpressionPosition methods.
If one of these methods is called then next generated bytecode will get passed
position. It's general treatment for most cases.
Unfortunately it doesn't work for Returns:
- debugger requires source positions exactly on kReturn bytecode in stepping
  implementation,
- BytecodeGenerator::BuildReturn and BytecodeGenerator::BuildAsyncReturn
  generates more then one bytecode and general solution will put return position
  on first generated bytecode,
- it's not easy to split BuildReturn function into two parts to allow something
  like following in BytecodeGenerator::VisitReturnStatement since generated
  bytecodes are actually controlled by execution_control().
..->BuildReturnPrologue();
..->SetReturnPosition(stmt);
..->Return();

In this CL we pass ReturnStatement through ExecutionControl and use it for
position when we emit return bytecode right here.

So this CL only will improve return position for returns inside of non-async
functions, I'll address async functions later.

[1] https://chromium-review.googlesource.com/c/543161/

Change-Id: Iede512c120b00c209990bf50c20e7d23dc0d65db
Reviewed-on: https://chromium-review.googlesource.com/560738
Commit-Queue: Aleksey Kozyatinskiy <kozyatinskiy@chromium.org>
Reviewed-by: Adam Klein <adamk@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46687}

In some codes flushing the registers was costly: we processed each
register whereas all the registers alone in their equivalence class need
not to be processed. We now overapproximate easily which classes are of
size 2 so as to save many iterations in the Flush() loop in some cases.

Bug: v8:6432
Change-Id: I945e151736e8a515263ac76312127d930fd20d74
Reviewed-on: https://chromium-review.googlesource.com/525795
Commit-Queue: Alexandre Talon <alexandret@google.com>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/master@{#45805}

This removes the execute_ flag, which was always the negation of top_level_.

R=rmcilroy@chromium.org
BUG=

Review-Url: https://codereview.chromium.org/2390163003
Cr-Commit-Position: refs/heads/master@{#39961}

This fixes a corner-case where the bytecode was using the <new.target>
register directly without going through the local variable. The value
might be clobbered because the deoptimizer doesn't properly restore the
value. The label will causes bytecode pipeline to be flushed and hence
ensure {BytecodeRegisterOptimizer} doesn't reuse <new.target> anymore.

R=rmcilroy@chromium.org
TEST=mjsunit/regress/regress-crbug-645103
BUG=chromium:645103

Review-Url: https://codereview.chromium.org/2325133002
Cr-Commit-Position: refs/heads/master@{#39306}

For historical reasons, the interpreter's bytecode expectations tests
required a type for the constant pool. This had two disadvantages:

 1. Strings and numbers were not visible in mixed pools, and
 2. Mismatches of pool types (e.g. when rebaselining) would cause parser
    errors

This removes the pool types, making everything 'mixed', but appending
the values to string and number valued constants. Specifying a pool type
in the *.golden header now prints a warning (for backwards compatibility).

BUG=v8:5350

Review-Url: https://codereview.chromium.org/2310103002
Cr-Commit-Position: refs/heads/master@{#39216}

The old code was using VariableMode, but that signal is both
over-pessimistic (some CONST and LET variables need no hole-initialization)
and inconsistent with other uses of the InitializationFlag enum (such
as %LoadLookupSlot).

This changes no observable behavior, but removes unnecessary hole
initialization and hole checks in a few places, including
block-scoped function declarations, super property lookups,
and new.target.

R=bmeurer@chromium.org, neis@chromium.org

Review-Url: https://codereview.chromium.org/2201193004
Cr-Commit-Position: refs/heads/master@{#38395}

This change requires a single pass over the register set during
bytecode pipeline flushes.

A few bytecode tests are updated too because the order of register
flushes is different.

BUG=v8:4280
LOG=N

Review-Url: https://codereview.chromium.org/2033013002
Cr-Commit-Position: refs/heads/master@{#36726}

Online optimization stage for reducing redundant transfers between registers.

BUG=V8:4280
LOG=N

Review-Url: https://codereview.chromium.org/1997653002
Cr-Commit-Position: refs/heads/master@{#36551}

Prints source position information alongside bytecode.

BUG=v8:4280
LOG=N

Review-Url: https://codereview.chromium.org/1963663002
Cr-Commit-Position: refs/heads/master@{#36171}

Bytecode expectations have been moved to external (.golden) files,
one per test. Each test in the suite builds a representation of the
the compiled bytecode using BytecodeExpectationsPrinter. The output is
then compared to the golden file. If the comparision fails, a textual
diff can be used to identify the discrepancies.

Only the test snippets are left in the cc file, which also allows to
make it more compact and meaningful. Leaving the snippets in the cc
file was a deliberate choice to allow keeping the "truth" about the
tests in the cc file, which will rarely change, as opposed to golden
files.

Golden files can be generated and kept up to date using
generate-bytecode-expectations, which also means that the test suite
can be batch updated whenever the bytecode or golden format changes.

The golden format has been slightly amended (no more comments about
`void*`, add size of the bytecode array) following the consideration
made while converting the tests.

There is also a fix: BytecodeExpectationsPrinter::top_level_ was left
uninitialized, leading to undefined behaviour.

BUG=v8:4280
LOG=N

Review URL: https://codereview.chromium.org/1717293002

Cr-Commit-Position: refs/heads/master@{#34285}