[Interpreter] Ensure ToBoolean bytecodes are correctly emitted at the start of basic blocks

[Interpreter] Ensure ToBoolean bytecodes are correctly emitted at the start of basic blocks

Existing code was assuming that 'lexical' blocks were the same as basic
blocks, therefore code which emitted jumps within a lexical block (e.g.,
logical or) would in some occassions incorrectly omit a necessary
ToBoolean.

This change removes Enter/LeaveBlock from BytecodeArrayBuilder and
instead tracks basic blocks via label bindings and jump operations. The
change also ensures we don't emit dead code at the end of a basic block,
and adds tests of the edge cases.

BUG=v8:4280
LOG=N

Committed: https://crrev.com/2e1bdea8ad80dc63fb5ed19396934db801e69fde
Cr-Commit-Position: refs/heads/master@{#31741}

[rmcilroy, 2015-11-02 17:38:58]

The CQ bit was checked by rmcilroy@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2015-11-02 17:39:12]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1406983010/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1406983010/1

[rmcilroy, 2015-11-02 17:39:16]

rmcilroy@chromium.org changed reviewers:
+ mythria@chromium.org, oth@chromium.org

[rmcilroy, 2015-11-02 17:39:17]

Orion / Mythri, PTAL, thanks.

[commit-bot: I haz the power, 2015-11-02 17:56:44]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-11-02 17:56:45]

Dry run: This issue passed the CQ dry run.

[oth, 2015-11-02 20:45:59]

lgtm. Very elegant. A handful of missing semi-colon nits.

https://codereview.chromium.org/1406983010/diff/1/test/cctest/interpreter/tes...
File test/cctest/interpreter/test-bytecode-generator.cc (right):

https://codereview.chromium.org/1406983010/diff/1/test/cctest/interpreter/tes...
test/cctest/interpreter/test-bytecode-generator.cc:4941: {"var a = 1; if (a || a
< 0) { return 1 }",
missing semi-colon

https://codereview.chromium.org/1406983010/diff/1/test/cctest/interpreter/tes...
test/cctest/interpreter/test-bytecode-generator.cc:4958: {"var a = 1; if (a && a
< 0) { return 1 }",
missing semi-colon

https://codereview.chromium.org/1406983010/diff/1/test/cctest/interpreter/tes...
test/cctest/interpreter/test-bytecode-generator.cc:4975: {"var a = 1; a = (a ||
a < 0) ? 2 : 3",
missing semi-colon

[mythria, 2015-11-03 11:02:00]

lgtm

https://codereview.chromium.org/1406983010/diff/1/test/cctest/interpreter/tes...
File test/cctest/interpreter/test-bytecode-generator.cc (right):

https://codereview.chromium.org/1406983010/diff/1/test/cctest/interpreter/tes...
test/cctest/interpreter/test-bytecode-generator.cc:1678: },
May be we can have another test where we have return in else and no return in
then. Something similar to
var a = 1;
 if (a) { 
  a = a + 1
 } else {
   return;
 }

[rmcilroy, 2015-11-03 11:10:12]

https://codereview.chromium.org/1406983010/diff/1/test/cctest/interpreter/tes...
File test/cctest/interpreter/test-bytecode-generator.cc (right):

https://codereview.chromium.org/1406983010/diff/1/test/cctest/interpreter/tes...
test/cctest/interpreter/test-bytecode-generator.cc:1678: },
On 2015/11/03 11:01:59, mythria wrote:
> May be we can have another test where we have return in else and no return in
> then. Something similar to
> var a = 1;
>  if (a) { 
>   a = a + 1
>  } else {
>    return;
>  }

SGTM, done.

https://codereview.chromium.org/1406983010/diff/1/test/cctest/interpreter/tes...
test/cctest/interpreter/test-bytecode-generator.cc:4941: {"var a = 1; if (a || a
< 0) { return 1 }",
On 2015/11/02 20:45:58, oth wrote:
> missing semi-colon

Done.

https://codereview.chromium.org/1406983010/diff/1/test/cctest/interpreter/tes...
test/cctest/interpreter/test-bytecode-generator.cc:4958: {"var a = 1; if (a && a
< 0) { return 1 }",
On 2015/11/02 20:45:58, oth wrote:
> missing semi-colon

Done.

https://codereview.chromium.org/1406983010/diff/1/test/cctest/interpreter/tes...
test/cctest/interpreter/test-bytecode-generator.cc:4975: {"var a = 1; a = (a ||
a < 0) ? 2 : 3",
On 2015/11/02 20:45:58, oth wrote:
> missing semi-colon

Done.

[rmcilroy, 2015-11-03 11:10:31]

The CQ bit was checked by rmcilroy@chromium.org

[rmcilroy, 2015-11-03 11:10:32]

The patchset sent to the CQ was uploaded after l-g-t-m from oth@chromium.org,
mythria@chromium.org
Link to the patchset: https://codereview.chromium.org/1406983010/#ps20001
(title: "Review comments.")

[commit-bot: I haz the power, 2015-11-03 11:10:36]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1406983010/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1406983010/20001

[commit-bot: I haz the power, 2015-11-03 11:27:57]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-11-03 11:28:17]

Patchset 2 (id:??) landed as
https://crrev.com/2e1bdea8ad80dc63fb5ed19396934db801e69fde
Cr-Commit-Position: refs/heads/master@{#31741}