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Patch by Ana Pazos. 1.Added support for v1ix and v1fx types. 2.Added Scalar Pairwise Reduce instructions. 3.Added initial implementation of Scalar Arithmetic instructions. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@191263 91177308-0d34-0410-b5e6-96231b3b80d8
198 lines
9.8 KiB
TableGen
198 lines
9.8 KiB
TableGen
//==-- AArch64CallingConv.td - Calling Conventions for ARM ----*- tblgen -*-==//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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// This describes the calling conventions for AArch64 architecture.
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//===----------------------------------------------------------------------===//
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// The AArch64 Procedure Call Standard is unfortunately specified at a slightly
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// higher level of abstraction than LLVM's target interface presents. In
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// particular, it refers (like other ABIs, in fact) directly to
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// structs. However, generic LLVM code takes the liberty of lowering structure
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// arguments to the component fields before we see them.
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//
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// As a result, the obvious direct map from LLVM IR to PCS concepts can't be
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// implemented, so the goals of this calling convention are, in decreasing
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// priority order:
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// 1. Expose *some* way to express the concepts required to implement the
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// generic PCS from a front-end.
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// 2. Provide a sane ABI for pure LLVM.
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// 3. Follow the generic PCS as closely as is naturally possible.
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//
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// The suggested front-end implementation of PCS features is:
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// * Integer, float and vector arguments of all sizes which end up in
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// registers are passed and returned via the natural LLVM type.
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// * Structure arguments with size <= 16 bytes are passed and returned in
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// registers as similar integer or composite types. For example:
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// [1 x i64], [2 x i64] or [1 x i128] (if alignment 16 needed).
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// * HFAs in registers follow rules similar to small structs: appropriate
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// composite types.
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// * Structure arguments with size > 16 bytes are passed via a pointer,
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// handled completely by the front-end.
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// * Structure return values > 16 bytes via an sret pointer argument.
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// * Other stack-based arguments (not large structs) are passed using byval
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// pointers. Padding arguments are added beforehand to guarantee a large
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// struct doesn't later use integer registers.
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//
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// N.b. this means that it is the front-end's responsibility (if it cares about
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// PCS compliance) to check whether enough registers are available for an
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// argument when deciding how to pass it.
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class CCIfAlign<int Align, CCAction A>:
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CCIf<"ArgFlags.getOrigAlign() == " # Align, A>;
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def CC_A64_APCS : CallingConv<[
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// SRet is an LLVM-specific concept, so it takes precedence over general ABI
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// concerns. However, this rule will be used by C/C++ frontends to implement
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// structure return.
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CCIfSRet<CCAssignToReg<[X8]>>,
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// Put ByVal arguments directly on the stack. Minimum size and alignment of a
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// slot is 64-bit.
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CCIfByVal<CCPassByVal<8, 8>>,
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// Canonicalise the various types that live in different floating-point
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// registers. This makes sense because the PCS does not distinguish Short
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// Vectors and Floating-point types.
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CCIfType<[v1i16, v2i8], CCBitConvertToType<f16>>,
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CCIfType<[v1i32, v4i8, v2i16, v1f32], CCBitConvertToType<f32>>,
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CCIfType<[v8i8, v4i16, v2i32, v2f32, v1i64, v1f64], CCBitConvertToType<f64>>,
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CCIfType<[v16i8, v8i16, v4i32, v2i64, v4f32, v2f64],
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CCBitConvertToType<f128>>,
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// PCS: "C.1: If the argument is a Half-, Single-, Double- or Quad- precision
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// Floating-point or Short Vector Type and the NSRN is less than 8, then the
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// argument is allocated to the least significant bits of register
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// v[NSRN]. The NSRN is incremented by one. The argument has now been
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// allocated."
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CCIfType<[v1i8], CCAssignToReg<[B0, B1, B2, B3, B4, B5, B6, B7]>>,
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CCIfType<[f16], CCAssignToReg<[H0, H1, H2, H3, H4, H5, H6, H7]>>,
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CCIfType<[f32], CCAssignToReg<[S0, S1, S2, S3, S4, S5, S6, S7]>>,
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CCIfType<[f64], CCAssignToReg<[D0, D1, D2, D3, D4, D5, D6, D7]>>,
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CCIfType<[f128], CCAssignToReg<[Q0, Q1, Q2, Q3, Q4, Q5, Q6, Q7]>>,
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// PCS: "C.2: If the argument is an HFA and there are sufficient unallocated
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// SIMD and Floating-point registers (NSRN - number of elements < 8), then the
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// argument is allocated to SIMD and Floating-point registers (with one
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// register per element of the HFA). The NSRN is incremented by the number of
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// registers used. The argument has now been allocated."
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//
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// N.b. As above, this rule is the responsibility of the front-end.
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// "C.3: If the argument is an HFA then the NSRN is set to 8 and the size of
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// the argument is rounded up to the nearest multiple of 8 bytes."
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//
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// "C.4: If the argument is an HFA, a Quad-precision Floating-point or Short
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// Vector Type then the NSAA is rounded up to the larger of 8 or the Natural
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// Alignment of the Argument's type."
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//
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// It is expected that these will be satisfied by adding dummy arguments to
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// the prototype.
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// PCS: "C.5: If the argument is a Half- or Single- precision Floating-point
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// type then the size of the argument is set to 8 bytes. The effect is as if
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// the argument had been copied to the least significant bits of a 64-bit
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// register and the remaining bits filled with unspecified values."
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CCIfType<[f16, f32], CCPromoteToType<f64>>,
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// PCS: "C.6: If the argument is an HFA, a Half-, Single-, Double- or Quad-
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// precision Floating-point or Short Vector Type, then the argument is copied
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// to memory at the adjusted NSAA. The NSAA is incremented by the size of the
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// argument. The argument has now been allocated."
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CCIfType<[f64], CCAssignToStack<8, 8>>,
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CCIfType<[f128], CCAssignToStack<16, 16>>,
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// PCS: "C.7: If the argument is an Integral Type, the size of the argument is
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// less than or equal to 8 bytes and the NGRN is less than 8, the argument is
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// copied to the least significant bits of x[NGRN]. The NGRN is incremented by
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// one. The argument has now been allocated."
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// First we implement C.8 and C.9 (128-bit types get even registers). i128 is
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// represented as two i64s, the first one being split. If we delayed this
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// operation C.8 would never be reached.
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CCIfType<[i64],
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CCIfSplit<CCAssignToRegWithShadow<[X0, X2, X4, X6], [X0, X1, X3, X5]>>>,
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// Note: the promotion also implements C.14.
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CCIfType<[i8, i16, i32], CCPromoteToType<i64>>,
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// And now the real implementation of C.7
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CCIfType<[i64], CCAssignToReg<[X0, X1, X2, X3, X4, X5, X6, X7]>>,
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// PCS: "C.8: If the argument has an alignment of 16 then the NGRN is rounded
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// up to the next even number."
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//
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// "C.9: If the argument is an Integral Type, the size of the argument is
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// equal to 16 and the NGRN is less than 7, the argument is copied to x[NGRN]
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// and x[NGRN+1], x[NGRN] shall contain the lower addressed double-word of the
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// memory representation of the argument. The NGRN is incremented by two. The
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// argument has now been allocated."
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//
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// Subtlety here: what if alignment is 16 but it is not an integral type? All
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// floating-point types have been allocated already, which leaves composite
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// types: this is why a front-end may need to produce i128 for a struct <= 16
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// bytes.
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// PCS: "C.10 If the argument is a Composite Type and the size in double-words
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// of the argument is not more than 8 minus NGRN, then the argument is copied
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// into consecutive general-purpose registers, starting at x[NGRN]. The
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// argument is passed as though it had been loaded into the registers from a
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// double-word aligned address with an appropriate sequence of LDR
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// instructions loading consecutive registers from memory (the contents of any
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// unused parts of the registers are unspecified by this standard). The NGRN
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// is incremented by the number of registers used. The argument has now been
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// allocated."
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//
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// Another one that's the responsibility of the front-end (sigh).
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// PCS: "C.11: The NGRN is set to 8."
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CCCustom<"CC_AArch64NoMoreRegs">,
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// PCS: "C.12: The NSAA is rounded up to the larger of 8 or the Natural
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// Alignment of the argument's type."
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//
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// PCS: "C.13: If the argument is a composite type then the argument is copied
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// to memory at the adjusted NSAA. The NSAA is by the size of the
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// argument. The argument has now been allocated."
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//
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// Note that the effect of this corresponds to a memcpy rather than register
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// stores so that the struct ends up correctly addressable at the adjusted
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// NSAA.
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// PCS: "C.14: If the size of the argument is less than 8 bytes then the size
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// of the argument is set to 8 bytes. The effect is as if the argument was
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// copied to the least significant bits of a 64-bit register and the remaining
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// bits filled with unspecified values."
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//
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// Integer types were widened above. Floating-point and composite types have
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// already been allocated completely. Nothing to do.
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// PCS: "C.15: The argument is copied to memory at the adjusted NSAA. The NSAA
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// is incremented by the size of the argument. The argument has now been
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// allocated."
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CCIfType<[i64], CCIfSplit<CCAssignToStack<8, 16>>>,
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CCIfType<[i64], CCAssignToStack<8, 8>>
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]>;
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// According to the PCS, X19-X30 are callee-saved, however only the low 64-bits
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// of vector registers (8-15) are callee-saved. The order here is is picked up
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// by PrologEpilogInserter.cpp to allocate stack slots, starting from top of
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// stack upon entry. This gives the customary layout of x30 at [sp-8], x29 at
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// [sp-16], ...
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def CSR_PCS : CalleeSavedRegs<(add (sequence "X%u", 30, 19),
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(sequence "D%u", 15, 8))>;
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// TLS descriptor calls are extremely restricted in their changes, to allow
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// optimisations in the (hopefully) more common fast path where no real action
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// is needed. They actually have to preserve all registers, except for the
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// unavoidable X30 and the return register X0.
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def TLSDesc : CalleeSavedRegs<(add (sequence "X%u", 29, 1),
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(sequence "Q%u", 31, 0))>;
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