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fix crash with templates containing shifts #6

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fix crash with templates containing shifts #6

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2d8d660
fix crash with templates containing shifts
facchinm Feb 23, 2016
eb6204b
C++: mitigate matching error on generics containing an expression
facchinm Feb 23, 2016
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18 changes: 17 additions & 1 deletion c.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1388,10 +1388,16 @@ static void skipToMatch (const char *const pair)
{
if (CollectingSignature)
vStringPut (Signature, c);


if (c == begin)
{
char s = cppGetc();
if (s == '<' && s == c) {
// templates can still contain "<<" ot "<<="
break;
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Doesn't breaking out of here put the parsing in a weird state, as now it will go forward parsing while inside a template parameter list?

(Also completely missed that there was already a pull request for this when one of my users pinged me about this being a problem w/FastLED).

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I can't really understand what you mean, this part of the patch looks for "<<" pattern inside a template, so going on parsing while ignoring the shift should be safe.
The other part takes care of not failing completely if we are unable to find the closing '>'

Whit this patch the snippet

template <int P> class c {};
c< 8 > bVar;
c< 1<<8 > aVar;
c< 1>>8 > cVar;

produces

bVar    /home/martino/arduino-builder/src/arduino.cc/builder/test/sketch11/sketch_fastleds.ino  /^c< 8 > bVar;$/;"  kind:variable   line:30
aVar    /home/martino/arduino-builder/src/arduino.cc/builder/test/sketch11/sketch_fastleds.ino  /^c< 1<<8 > aVar;$/;"   kind:variable   line:31
cVar    /home/martino/arduino-builder/src/arduino.cc/builder/test/sketch11/sketch_fastleds.ino  /^c< 1>>8 > cVar;$/;"   kind:variable   line:32

Should be ok, right? 😄

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There's still cases that it will miss - for example:

template <int P> class c {};
c< 8 > bVar;
c< 1<<8 > aVar;

template<int X> func( c< 1<<X> & aParam) {
}

it will fail to parse out the definition for func, only dumping out aVar/bVar - because it's punted on trying to keep things balanced, it's just going to walk forward until the {.

The desired output would be:

./ctags -u --language-force=c++ -f - --c++-kinds=svpf --fields=KSTtzns --line-directives /tmp/x.cpp --verbose
bVar    /tmp/x.cpp  /^c< 8 > bVar;$/;"  kind:variable   line:2
aVar    /tmp/x.cpp  /^c< 1<<8 > aVar;$/;"   kind:variable   line:3
func    /tmp/x.cpp  /^template<int X> func( c< 1<<X> & aVar) {$/;"  kind:function   line:5  signature:( c< 1<<X> & aVar)    returntype:template

} else {
cppUngetc(s);
}
++matchLevel;
if (braceFormatting && getDirectiveNestLevel () != initialLevel)
{
Expand All @@ -1408,6 +1414,16 @@ static void skipToMatch (const char *const pair)
break;
}
}
/* early out if matching "<>" and we encounter a ";" or "{" to mitigate
* match problems with C++ generics containing a static expression like
* foo<X<Y> bar;
* normally neither ";" nor "{" could appear inside "<>" anyway. */
else if (isLanguage (Lang_cpp) && begin == '<' &&
(c == ';' || c == '{'))
{
cppUngetc (c);
break;
}
}
if (c == EOF)
{
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