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Mantis - GCC-XML
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Viewing Issue Advanced Details |
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ID:
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Category:
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Severity:
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Reproducibility:
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Date Submitted:
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Last Update:
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9915 |
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major |
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2009-11-18 06:40 |
2009-11-18 16:49 |
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Reporter:
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Gustavo J. A. M. Carneiro |
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Assigned To:
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Brad King |
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Priority:
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normal |
OS Version:
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Status:
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closed |
Product Version:
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Product Build:
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Resolution:
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suspended |
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Projection:
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none |
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ETA:
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none |
Fixed in Version:
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Summary:
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0009915: parameter default value parsed wrong with template class |
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Description:
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A simple constructor:
Test (Time lifetime = MilliSeconds (0));
In this case, MilliSeconds is a function that returns Time, which is a templated instantiation class. GCC-XML reports the default value as default="MilliSeconds(uint64_t)()", which is clearly wrong. After going through pygccxml, what I get is MilliSeconds(). |
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Steps To Reproduce:
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Additional Information:
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A bug I found in NS-3 (www.nsnam.org) Python bindings.
To reproduce, parse the attached test file:
$ gccxml -I . -fxml=/tmp/test.xml test.h
$ grep /tmp/test.xml -e Constructor -A10 |grep Milli
<Argument name="lifetime" type="_89" location="f2:21" file="f2" line="21" default="MilliSeconds(uint64_t)()"/>
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Attached Files:
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 test.h [^] (354 bytes) 2009-11-18 06:40 |
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Issue History |
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Date Modified |
Username |
Field |
Change |
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2009-11-18 06:40 |
Gustavo J. A. M. Carneiro |
New Issue |
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2009-11-18 06:40 |
Gustavo J. A. M. Carneiro |
File Added: test.h |
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2009-11-18 15:28 |
Roman Yakovenko |
Note Added: 0018478 |
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2009-11-18 15:33 |
Roman Yakovenko |
Note Edited: 0018478 |
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2009-11-18 16:41 |
Brad King |
Status |
new => assigned |
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2009-11-18 16:41 |
Brad King |
Assigned To |
=> Brad King |
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2009-11-18 16:48 |
Brad King |
Note Added: 0018483 |
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2009-11-18 16:49 |
Brad King |
Status |
assigned => closed |
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2009-11-18 16:49 |
Brad King |
Resolution |
open => suspended |
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Notes |
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(0018478)
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Roman Yakovenko
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2009-11-18 15:28
(edited on: 2009-11-18 15:33) |
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In order to dump right a default argument, GCCXML has to implement the following algorithm:
* split the default argument expression to identifiers
* resolve every identifier ( find out fully qualified name )
* re-write the expression using fully qualified identifiers
This is a huge amount of work and I am not sure it worse it. After all, the work around is easy
* ask the user to create a new function overload
* ask the user to specify the default argument expression in a code generator.
pygccxml uses second approach and many users seems to be happy with it, once they understand the complexity of the task.
In pygccxml package, I implemented few work-around's to the problem:
* resolve enum value:
* remove double call
- if written x()() pygccxml will replace it with x()
* fix invalid integers
- if the argument type is "int" and default value is [abcdef][0-9] then add 0x to the expression
* sometimes the default value expression is a call to the argument type constructor
- pygccxml will resolve the constructor identifier
I am pretty sure, that GCCXML should NOT implement any of them. The partial solution will only confuse the users more.
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(0018483)
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Brad King
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2009-11-18 16:48
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Thanks, Roman.
So, the problem is that the original user-specified default expression is simply lost by the time our XML dump code sees it. The default argument attribute in the XML is printed by gcc's expression dump code. That code is normally used just to print diagnostics, so it is not intended to create an expression that will re-parse correctly. Generating an expression that re-parses correctly is a very difficult problem in C++. |
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