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f09378397e
per-function subtarget. Currently, code-gen passes the default or generic subtarget to the constructors of MCInstPrinter subclasses (see LLVMTargetMachine::addPassesToEmitFile), which enables some targets (AArch64, ARM, and X86) to change their instprinter's behavior based on the subtarget feature bits. Since the backend can now use different subtargets for each function, instprinter has to be changed to use the per-function subtarget rather than the default subtarget. This patch takes the first step towards enabling instprinter to change its behavior based on the per-function subtarget. It adds a bit "PassSubtarget" to AsmWriter which tells table-gen to pass a reference to MCSubtargetInfo to the various print methods table-gen auto-generates. I will follow up with changes to instprinters of AArch64, ARM, and X86. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233411 91177308-0d34-0410-b5e6-96231b3b80d8
//===---------------------------------------------------------------------===// // MSP430 backend. //===---------------------------------------------------------------------===// DISCLAIMER: Thid backend should be considered as highly experimental. I never seen nor worked with this MCU, all information was gathered from datasheet only. The original intention of making this backend was to write documentation of form "How to write backend for dummies" :) Thes notes hopefully will be available pretty soon. Some things are incomplete / not implemented yet (this list surely is not complete as well): 1. Verify, how stuff is handling implicit zext with 8 bit operands (this might be modelled currently in improper way - should we need to mark the superreg as def for every 8 bit instruction?). 2. Libcalls: multiplication, division, remainder. Note, that calling convention for libcalls is incomptible with calling convention of libcalls of msp430-gcc (these cannot be used though due to license restriction). 3. Implement multiplication / division by constant (dag combiner hook?). 4. Implement non-constant shifts. 5. Implement varargs stuff. 6. Verify and fix (if needed) how's stuff playing with i32 / i64. 7. Implement floating point stuff (softfp?) 8. Implement instruction encoding for (possible) direct code emission in the future. 9. Since almost all instructions set flags - implement brcond / select in better way (currently they emit explicit comparison). 10. Handle imm in comparisons in better way (see comment in MSP430InstrInfo.td) 11. Implement hooks for better memory op folding, etc.