[llvm-dev] Is there a reason why MCAsmStreamer class doesn't have its own .h file?
Fraser Cormack via llvm-dev
llvm-dev at lists.llvm.org
Thu Feb 4 03:50:54 PST 2016
I know I'm a bit late to the party, but I wanted to chime in and say
that in my past two backends we've had to copy/paste MCAsmStreamer into
our target just to override one or two methods.
For instance, in our current project we need to override:
EmitLabel() - We must escape certain characters
EmitBytes() - We must also escape and disallow certain characters, and
fall back to emitting byte arrays
EmitLocalCommonSymbol() - We don't want the hard-coded "lcomm" symbol
EmitAssignment() - We don't use the hard-coded syntax
There will probably be more things we need to change further down the
I believe in the last project we had to override EmitLabel() because it
used label prefix instead of a label suffix.
Some of these things might be fixable using the current architecture
(like putting "lcomm" into MCAsmInfo) or by moving more into
MCTargetStreamer and allowing that to do the entire job, instead of only
part of it. For instance, I see MCAsmStreamer::EmitLabel calls
MCStreamer::EmitLabel which calls MCTargetStreamer::EmitLabel, but then
after all that happens, the MCAsmStreamer implementation still
unconditionally does its own logic.
That, or it could just allow targets to inherit from it as they like. Is
there a reason why it couldn't or shouldn't be done?
On 22/01/16 00:04, Craig Topper via llvm-dev wrote:
> Isn't it also marked 'final' so it can't be inherited from anyway? What's
> your need to inherit from it?
> On Thu, Jan 21, 2016 at 2:42 PM, Rail Shafigulin via llvm-dev <
> llvm-dev at lists.llvm.org> wrote:
>> Does anybody know if there is a particular reason why MCAsmStreamer
>> doesn't have its own .h file?
>> It seems like it is a good idea to have this class declared as its own
>> module ( its own .cpp and .h files). That would make it easier to inherit
>> from it if there is a need (like in my current case).
>> Any help is appreciated.
>> Rail Shafigulin
>> Software Engineer
>> Esencia Technologies
>> LLVM Developers mailing list
>> llvm-dev at lists.llvm.org
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