Thomas Lively 7987888a3f [WebAssembly][InstrEmitter] Foundation for multivalue call lowering ... Summary: WebAssembly is unique among upstream targets in that it does not at any point use physical registers to store values. Instead, it uses virtual registers to model positions in its value stack. This means that some target-independent lowering activities that would use physical registers need to use virtual registers instead for WebAssembly and similar downstream targets. This CL generalizes the existing `usesPhysRegsForPEI` lowering hook to `usesPhysRegsForValues` in preparation for using it in more places. One such place is in InstrEmitter for instructions that have variadic defs. On register machines, it only makes sense for these defs to be physical registers, but for WebAssembly they must be virtual registers like any other values. This CL changes InstrEmitter to check the new target lowering hook to determine whether variadic defs should be physical or virtual registers. These changes are necessary to support a generalized CALL instruction for WebAssembly that is capable of returning an arbitrary number of arguments. Fully implementing that instruction will require additional changes that are described in comments here but left for a follow up commit. Reviewers: aheejin, dschuff, qcolombet Subscribers: sbc100, jgravelle-google, hiraditya, sunfish, llvm-commits Tags: #llvm Differential Revision: https://reviews.llvm.org/D71484		2020-01-21 11:13:46 -08:00
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llvm	[WebAssembly][InstrEmitter] Foundation for multivalue call lowering	2020-01-21 11:13:46 -08:00
llvm-c	Move the sysroot attribute from DIModule to DICompileUnit	2020-01-17 12:55:40 -08:00