Hi, Richard,
You are right, setting UNKNOWN_LOCATION will not affect addr2line
result. Here is the updated patch:
Passed bootstrap and gcc regression tests.
Is it ok for trunk?
Thanks,
Dehao
Index: tree-inline.c
===================================================================
--- tree-inline.c (revision 188926)
+++ tree-inline.c (working copy)
@@ -3836,8 +3836,7 @@
/* Set input_location here so we get the right instantiation context
if we call instantiate_decl from inlinable_function_p. */
saved_location = input_location;
- if (gimple_has_location (stmt))
- input_location = gimple_location (stmt);
+ input_location = gimple_location (stmt);
/* From here on, we're only interested in CALL_EXPRs. */
if (gimple_code (stmt) != GIMPLE_CALL)
On Mon, Jun 25, 2012 at 10:00 PM, Richard Guenther
<richard.guent...@gmail.com> wrote:
> On Mon, Jun 25, 2012 at 3:48 PM, Dehao Chen <de...@google.com> wrote:
>> Hi, Richard,
>>
>> Thanks for the prompt response.
>>
>> On Mon, Jun 25, 2012 at 8:02 PM, Richard Guenther
>> <richard.guent...@gmail.com> wrote:
>>> On Mon, Jun 25, 2012 at 1:43 PM, Dehao Chen <de...@google.com> wrote:
>>>> During function inlining, a lexical block is added for each cloned
>>>> callee, and source info is attached to this block for addr2line to
>>>> derive the inline stack.
>>>
>>> Well - the bug is then clearly
>>>
>>> /* Set input_location here so we get the right instantiation context
>>> if we call instantiate_decl from inlinable_function_p. */
>>> saved_location = input_location;
>>> if (gimple_has_location (stmt))
>>> input_location = gimple_location (stmt)
>>>
>>> which retails input_location instead of setting it to UNKNOWN_LOCATION.
>>>
>>> Not adding a BLOCK will make debug information incorrect, no?
>>
>> The only case I can think of that gimple_has_location is false for
>> call stmt is for function split.
>>
>> If we have function foo, which is split into:
>>
>> foo
>> foo.part1
>>
>> And a callsite foo->foo.part1 is created in foo.
>>
>> If the ipa-inline decided to inline this callsite, for an instruction
>> in foo.part1, it will have an inline stack of size 2. In the original
>> buggy code, the bottom of the inline stack will be random. Using your
>> proposed approach, the bottom of the inline stack would be
>> UNKNOW_LOCATION, but still has two levels. For function split, this
>> inline will not create any lexical block, but resumes the original
>> lexical block before the split. Thus my change simply not add a new
>> lexical block. Do you think this makes sense?
>
> I don't think it behaves sensibly for any other call without a location.
> Basically you assume that this only happens for split functions but
> I don't see why that should be true. Why would BLOCKs with
> UNKOWN_LOCATION have any effect on addr2line anyways?
> That seems to be something to check and fix.
>
> Richard.
>
>
>> Thanks,
>> Dehao
>>
>>
>>>
>>>> However, some callsites do not have source
>>>> information attached to it. Adding a lexical block would be misleading
>>>> in this case. E.g. If a function is split, when the split callsite is
>>>> inlined back, the cloned callee should stay in the same lexical block
>>>> with its caller. This patch ensures that lexical blocks are only added
>>>> when the callsite has source location info in it.
>>>>
>>>> Bootstrapped and passed gcc regression tests.
>>>>
>>>> Is it ok for trunk?
>>>
>>> I'd rather see an unconditional set of input_location from gimple_location
>>> of the statement.
>>>
>>> Richard.
>>>
>>>> Thanks,
>>>> Dehao
>>>>
>>>> gcc/ChangeLog:
>>>> 2012-06-25 Dehao Chen <de...@google.com>
>>>>
>>>> * tree-profile.c: (expand_call_inline): Make a new lexical block
>>>> only
>>>
>>> ^^^^^
>>> tree-inline.c
>>>
>>>> when the call stmt has source location.
>>>>
>>>> Index: gcc/tree-inline.c
>>>> ===================================================================
>>>> --- gcc/tree-inline.c (revision 188926)
>>>> +++ gcc/tree-inline.c (working copy)
>>>> @@ -3950,10 +3950,17 @@
>>>> actual inline expansion of the body, and a label for the return
>>>> statements within the function to jump to. The type of the
>>>> statement expression is the return type of the function call. */
>>>> - id->block = make_node (BLOCK);
>>>> - BLOCK_ABSTRACT_ORIGIN (id->block) = fn;
>>>> - BLOCK_SOURCE_LOCATION (id->block) = input_location;
>>>> - prepend_lexical_block (gimple_block (stmt), id->block);
>>>> + if (gimple_has_location (stmt))
>>>> + {
>>>> + id->block = make_node (BLOCK);
>>>> + BLOCK_ABSTRACT_ORIGIN (id->block) = fn;
>>>> + BLOCK_SOURCE_LOCATION (id->block) = input_location;
>>>
>>> Please use gimple_location (stmt) instead of input_location (yes, I realize
>>> its set from that).
>>>
>>>> + prepend_lexical_block (gimple_block (stmt), id->block);
>>>> + }
>>>> + else
>>>> + {
>>>> + id->block = gimple_block (stmt);
>>>> + }
>>>
>>>> /* Local declarations will be replaced by their equivalents in this
>>>> map. */
