In the ARM backend, functions (and other 32 bit constants) are placed
in a pool and loaded when needed.
A problem with this is that ".weak" directives must be printed in the
pool. This is not supported in the standard printer, so I think that I
have found the first use for MachineConstantPoolValue 
Creating the constant is easy, but I have two problems:
1) what are the methods getExistingMachineCPValue and
AddSelectionDAGCSEId supposed to do?
2) printing is hard because we are outside the AsmPrinter.
In my current hack I am printing from
ARMAsmPrinter::EmitMachineConstantPoolValue 
Since this problem might also be significant to x86 (see my previous
email), maybe we should just teach the pool printer to emit ".weak"
directives...
Best Regards,
Rafael
P.S.: rest assured that what is attached is just a demo hack and will
not be committed
llvm-pool-hack.patch (4.26 KB)
ARMAsmPrinter.h (547 Bytes)
In the ARM backend, functions (and other 32 bit constants) are placed
in a pool and loaded when needed.
Has this approach been replaced with your later constant pool patch?
-Chris
A problem with this is that ".weak" directives must be printed in the
pool. This is not supported in the standard printer, so I think that I
have found the first use for MachineConstantPoolValue
Creating the constant is easy, but I have two problems:
1) what are the methods getExistingMachineCPValue and
AddSelectionDAGCSEId supposed to do?
2) printing is hard because we are outside the AsmPrinter.
In my current hack I am printing from
ARMAsmPrinter::EmitMachineConstantPoolValue
Since this problem might also be significant to x86 (see my previous
email), maybe we should just teach the pool printer to emit ".weak"
directives...
Best Regards,
Rafael
P.S.: rest assured that what is attached is just a demo hack and will
not be committed
-Chris
Yes. The constant pool patch solves the problem in a much simpler way.
Best Regards,
Rafael