[csa] add utilities for printf-style debugging

[csa] add utilities for printf-style debugging

Adds CSA::Print(const char* s), which generates a runtime call to
Runtime::kGlobalPrint with a line-terminated ASCII string constant,
and CSA::DebugPrint(const char* prefix, Node* tagged_value), which
emits a runtime call to Runtime::kDebugPrint() with the tagged
value, optionally prefixed by an ascii string constant.

These simplify debugging TF builtins by providing a tool to easily
observe the contents of values at arbitrary points in a program,
without stepping endlessly through assembly in a debugger, and to
easily observe the path taken through a TF builtin.

These methods do not generate code in release builds.

BUG=v8:5268
R=ishell@chromium.org, danno@chromium.org, bmeurer@chromium.org

Review-Url: https://codereview.chromium.org/2651673003
Cr-Commit-Position: refs/heads/master@{#42660}
Committed: https://chromium.googlesource.com/v8/v8/+/c18d4216a431d54813e79a7719e17a30c8a3ec24

[caitp, 2017-01-23 19:12:58]

PTAL

This doesn't do much, but it makes it easier to write quick prints to more
easily see the path taken through a builtin, and to easily inspect a tagged
value at a particular point (without invoking
`_v8_internal_Print_Object(<register>)` manually in a debugger), which is nice.

I've found it very useful during the implementation of the async iteration
proposal, and think it could help debugging issues with these things more
quickly

[caitp, 2017-01-23 19:22:15]

Description was changed from

==========
[code-stub-assembler] add utilities for printf-style debugging

Adds CSA::Print(const char* s), which generates a runtime call to
Runtime::kGlobalPrint with a line-terminated ASCII string constant,
and CSA::DebugPrint(const char* prefix, Node* tagged_value), which
emits a runtime call to Runtime::kDebugPrint() with the tagged
value, optionally prefixed by an ascii string constant.

These simplify debugging TF builtins by providing a tool to easily
observe the contents of values at arbitrary points in a program,
without stepping endlessly through assembly in a debugge, and to
easily observe the path taken through a TF builtin.

These methods do not generate code in release builds.

BUG=v8:5268
R=ishell@chromium.org, danno@chromium.org, bmeurer@chromium.org
==========

to

==========
[code-stub-assembler] add utilities for printf-style debugging

Adds CSA::Print(const char* s), which generates a runtime call to
Runtime::kGlobalPrint with a line-terminated ASCII string constant,
and CSA::DebugPrint(const char* prefix, Node* tagged_value), which
emits a runtime call to Runtime::kDebugPrint() with the tagged
value, optionally prefixed by an ascii string constant.

These simplify debugging TF builtins by providing a tool to easily
observe the contents of values at arbitrary points in a program,
without stepping endlessly through assembly in a debugger, and to
easily observe the path taken through a TF builtin.

These methods do not generate code in release builds.

BUG=v8:5268
R=ishell@chromium.org, danno@chromium.org, bmeurer@chromium.org
==========

[Igor Sheludko, 2017-01-24 09:24:24]

Description was changed from

==========
[code-stub-assembler] add utilities for printf-style debugging

Adds CSA::Print(const char* s), which generates a runtime call to
Runtime::kGlobalPrint with a line-terminated ASCII string constant,
and CSA::DebugPrint(const char* prefix, Node* tagged_value), which
emits a runtime call to Runtime::kDebugPrint() with the tagged
value, optionally prefixed by an ascii string constant.

These simplify debugging TF builtins by providing a tool to easily
observe the contents of values at arbitrary points in a program,
without stepping endlessly through assembly in a debugger, and to
easily observe the path taken through a TF builtin.

These methods do not generate code in release builds.

BUG=v8:5268
R=ishell@chromium.org, danno@chromium.org, bmeurer@chromium.org
==========

to

==========
[csa] add utilities for printf-style debugging

Adds CSA::Print(const char* s), which generates a runtime call to
Runtime::kGlobalPrint with a line-terminated ASCII string constant,
and CSA::DebugPrint(const char* prefix, Node* tagged_value), which
emits a runtime call to Runtime::kDebugPrint() with the tagged
value, optionally prefixed by an ascii string constant.

These simplify debugging TF builtins by providing a tool to easily
observe the contents of values at arbitrary points in a program,
without stepping endlessly through assembly in a debugger, and to
easily observe the path taken through a TF builtin.

These methods do not generate code in release builds.

BUG=v8:5268
R=ishell@chromium.org, danno@chromium.org, bmeurer@chromium.org
==========

[Igor Sheludko, 2017-01-24 09:24:56]

lgtm.

BTW, we have a set of useful gbd macros defined in tools/gdbinit. So instead of
typing 
  call _v8_internal_Print_Object(<register>)
you can just type
  job <register>
or
  job 0xblahblah

https://codereview.chromium.org/2651673003/diff/20001/src/code-stub-assembler.h
File src/code-stub-assembler.h (right):

https://codereview.chromium.org/2651673003/diff/20001/src/code-stub-assembler...
src/code-stub-assembler.h:1172: void DebugPrint(const char* prefix, Node*
tagged_value);
How about calling all these functions just Print()? Otherwise the Print() looks
like it is semantically different than DebugPrint().

[caitp, 2017-01-24 13:16:04]

On 2017/01/24 09:24:56, Igor Sheludko wrote:
> lgtm.
> 
> BTW, we have a set of useful gbd macros defined in tools/gdbinit. So instead
of
> typing 
>   call _v8_internal_Print_Object(<register>)
> you can just type
>   job <register>
> or
>   job 0xblahblah

Yeah, I am mainly using lldb, which doesn't seem to understand gdbinit, far as I
can tell. I keep meaning to write a similar python script for lldb, but usually
just end up copy/pasting commands from the gdbinit file. But even so, using the
printf approach can avoid spending a lot of time stepping through large chunks
of assembly for the right moment.

https://codereview.chromium.org/2651673003/diff/20001/src/code-stub-assembler.h
File src/code-stub-assembler.h (right):

https://codereview.chromium.org/2651673003/diff/20001/src/code-stub-assembler...
src/code-stub-assembler.h:1172: void DebugPrint(const char* prefix, Node*
tagged_value);
On 2017/01/24 09:24:56, Igor Sheludko wrote:
> How about calling all these functions just Print()? Otherwise the Print()
looks
> like it is semantically different than DebugPrint().

Sounds good

[caitp, 2017-01-24 13:30:37]

https://codereview.chromium.org/2651673003/diff/40001/src/code-stub-assembler.cc
File src/code-stub-assembler.cc (right):

https://codereview.chromium.org/2651673003/diff/40001/src/code-stub-assembler...
src/code-stub-assembler.cc:8421: CallRuntime(Runtime::kGlobalPrint,
NoContextConstant(), tagged_value);
Is there any way to assert that the value outputs from the `tagged_value` node
have a tagged representation during graph generation?

[Igor Sheludko, 2017-01-24 14:20:08]

On 2017/01/24 13:30:37, caitp wrote:
>
https://codereview.chromium.org/2651673003/diff/40001/src/code-stub-assembler.cc
> File src/code-stub-assembler.cc (right):
> 
>
https://codereview.chromium.org/2651673003/diff/40001/src/code-stub-assembler...
> src/code-stub-assembler.cc:8421: CallRuntime(Runtime::kGlobalPrint,
> NoContextConstant(), tagged_value);
> Is there any way to assert that the value outputs from the `tagged_value` node
> have a tagged representation during graph generation?

The machine graph verifier should check that (it's on by default in debug mode).

[caitp, 2017-01-24 15:11:20]

The CQ bit was checked by caitp@igalia.com

[caitp, 2017-01-24 15:11:20]

The patchset sent to the CQ was uploaded after l-g-t-m from ishell@chromium.org
Link to the patchset: https://codereview.chromium.org/2651673003/#ps40001
(title: "rename DebugPrint macro to Print")

[commit-bot: I haz the power, 2017-01-24 15:11:25]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-01-24 15:17:57]

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

[commit-bot: I haz the power, 2017-01-24 15:17:58]

Try jobs failed on following builders:
  v8_linux_chromium_gn_rel on master.tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_linux_chromium_gn_rel/bu...)

[caitp, 2017-01-25 15:01:56]

The CQ bit was checked by caitp@igalia.com

[commit-bot: I haz the power, 2017-01-25 15:02:02]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-01-25 15:45:58]

CQ is committing da patch.

Bot data: {"patchset_id": 40001, "attempt_start_ts": 1485356516065210,
"parent_rev": "7c30fcf22dfd3a22874b4525bcfbe59e8786635b", "commit_rev":
"c18d4216a431d54813e79a7719e17a30c8a3ec24"}

[commit-bot: I haz the power, 2017-01-25 15:46:02]

Description was changed from

==========
[csa] add utilities for printf-style debugging

Adds CSA::Print(const char* s), which generates a runtime call to
Runtime::kGlobalPrint with a line-terminated ASCII string constant,
and CSA::DebugPrint(const char* prefix, Node* tagged_value), which
emits a runtime call to Runtime::kDebugPrint() with the tagged
value, optionally prefixed by an ascii string constant.

These simplify debugging TF builtins by providing a tool to easily
observe the contents of values at arbitrary points in a program,
without stepping endlessly through assembly in a debugger, and to
easily observe the path taken through a TF builtin.

These methods do not generate code in release builds.

BUG=v8:5268
R=ishell@chromium.org, danno@chromium.org, bmeurer@chromium.org
==========

to

==========
[csa] add utilities for printf-style debugging

Adds CSA::Print(const char* s), which generates a runtime call to
Runtime::kGlobalPrint with a line-terminated ASCII string constant,
and CSA::DebugPrint(const char* prefix, Node* tagged_value), which
emits a runtime call to Runtime::kDebugPrint() with the tagged
value, optionally prefixed by an ascii string constant.

These simplify debugging TF builtins by providing a tool to easily
observe the contents of values at arbitrary points in a program,
without stepping endlessly through assembly in a debugger, and to
easily observe the path taken through a TF builtin.

These methods do not generate code in release builds.

BUG=v8:5268
R=ishell@chromium.org, danno@chromium.org, bmeurer@chromium.org

Review-Url: https://codereview.chromium.org/2651673003
Cr-Commit-Position: refs/heads/master@{#42660}
Committed:
https://chromium.googlesource.com/v8/v8/+/c18d4216a431d54813e79a7719e17a30c8a...
==========

[commit-bot: I haz the power, 2017-01-25 15:46:03]

Committed patchset #3 (id:40001) as
https://chromium.googlesource.com/v8/v8/+/c18d4216a431d54813e79a7719e17a30c8a...