130 lines
4.8 KiB
C
130 lines
4.8 KiB
C
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//===-- AArch64SMEAttributes.h - Helper for interpreting SME attributes -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_LIB_TARGET_AARCH64_UTILS_AARCH64SMEATTRIBUTES_H
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#define LLVM_LIB_TARGET_AARCH64_UTILS_AARCH64SMEATTRIBUTES_H
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#include "llvm/IR/Function.h"
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namespace llvm {
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class Function;
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class CallBase;
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class AttributeList;
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/// SMEAttrs is a utility class to parse the SME ACLE attributes on functions.
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/// It helps determine a function's requirements for PSTATE.ZA and PSTATE.SM. It
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/// has interfaces to query whether a streaming mode change or lazy-save
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/// mechanism is required when going from one function to another (e.g. through
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/// a call).
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class SMEAttrs {
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unsigned Bitmask;
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public:
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enum class StateValue {
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None = 0,
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In = 1, // aarch64_in_zt0
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Out = 2, // aarch64_out_zt0
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InOut = 3, // aarch64_inout_zt0
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Preserved = 4, // aarch64_preserves_zt0
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New = 5 // aarch64_new_zt0
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};
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// Enum with bitmasks for each individual SME feature.
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enum Mask {
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Normal = 0,
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SM_Enabled = 1 << 0, // aarch64_pstate_sm_enabled
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SM_Compatible = 1 << 1, // aarch64_pstate_sm_compatible
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SM_Body = 1 << 2, // aarch64_pstate_sm_body
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ZA_Shared = 1 << 3, // aarch64_pstate_sm_shared
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ZA_New = 1 << 4, // aarch64_pstate_sm_new
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ZA_Preserved = 1 << 5, // aarch64_pstate_sm_preserved
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SME_ABI_Routine = 1 << 6, // Used for SME ABI routines to avoid lazy saves
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ZT0_Shift = 7,
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ZT0_Mask = 0b111 << ZT0_Shift
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};
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SMEAttrs(unsigned Mask = Normal) : Bitmask(0) { set(Mask); }
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SMEAttrs(const Function &F) : SMEAttrs(F.getAttributes()) {}
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SMEAttrs(const CallBase &CB);
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SMEAttrs(const AttributeList &L);
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SMEAttrs(StringRef FuncName);
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void set(unsigned M, bool Enable = true);
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// Interfaces to query PSTATE.SM
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bool hasStreamingBody() const { return Bitmask & SM_Body; }
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bool hasStreamingInterface() const { return Bitmask & SM_Enabled; }
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bool hasStreamingInterfaceOrBody() const {
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return hasStreamingBody() || hasStreamingInterface();
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}
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bool hasStreamingCompatibleInterface() const {
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return Bitmask & SM_Compatible;
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}
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bool hasNonStreamingInterface() const {
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return !hasStreamingInterface() && !hasStreamingCompatibleInterface();
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}
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bool hasNonStreamingInterfaceAndBody() const {
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return hasNonStreamingInterface() && !hasStreamingBody();
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}
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/// \return true if a call from Caller -> Callee requires a change in
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/// streaming mode.
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bool requiresSMChange(const SMEAttrs &Callee) const;
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// Interfaces to query PSTATE.ZA
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bool hasNewZABody() const { return Bitmask & ZA_New; }
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bool sharesZA() const { return Bitmask & ZA_Shared; }
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bool hasSharedZAInterface() const { return sharesZA() || sharesZT0(); }
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bool hasPrivateZAInterface() const { return !hasSharedZAInterface(); }
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bool preservesZA() const { return Bitmask & ZA_Preserved; }
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bool hasZAState() const { return hasNewZABody() || sharesZA(); }
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bool requiresLazySave(const SMEAttrs &Callee) const {
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return hasZAState() && Callee.hasPrivateZAInterface() &&
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!(Callee.Bitmask & SME_ABI_Routine);
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}
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// Interfaces to query ZT0 State
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static StateValue decodeZT0State(unsigned Bitmask) {
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return static_cast<StateValue>((Bitmask & ZT0_Mask) >> ZT0_Shift);
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}
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static unsigned encodeZT0State(StateValue S) {
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return static_cast<unsigned>(S) << ZT0_Shift;
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}
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bool isNewZT0() const { return decodeZT0State(Bitmask) == StateValue::New; }
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bool isInZT0() const { return decodeZT0State(Bitmask) == StateValue::In; }
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bool isOutZT0() const { return decodeZT0State(Bitmask) == StateValue::Out; }
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bool isInOutZT0() const {
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return decodeZT0State(Bitmask) == StateValue::InOut;
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}
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bool isPreservesZT0() const {
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return decodeZT0State(Bitmask) == StateValue::Preserved;
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}
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bool sharesZT0() const {
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StateValue State = decodeZT0State(Bitmask);
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return State == StateValue::In || State == StateValue::Out ||
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State == StateValue::InOut || State == StateValue::Preserved;
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}
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bool hasZT0State() const { return isNewZT0() || sharesZT0(); }
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bool requiresPreservingZT0(const SMEAttrs &Callee) const {
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return hasZT0State() && !Callee.sharesZT0();
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}
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bool requiresDisablingZABeforeCall(const SMEAttrs &Callee) const {
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return hasZT0State() && !hasZAState() && Callee.hasPrivateZAInterface() &&
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!(Callee.Bitmask & SME_ABI_Routine);
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}
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bool requiresEnablingZAAfterCall(const SMEAttrs &Callee) const {
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return requiresLazySave(Callee) || requiresDisablingZABeforeCall(Callee);
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}
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};
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} // namespace llvm
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#endif // LLVM_LIB_TARGET_AARCH64_UTILS_AARCH64SMEATTRIBUTES_H
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