From 319f4c03ba2909c7240ac157cc46216bf1518c10 Mon Sep 17 00:00:00 2001 From: Sander de Smalen Date: Fri, 2 Feb 2024 11:56:38 +0000 Subject: [PATCH] [Clang][AArch64] Emit 'unimplemented' diagnostic for SME (#80295) When a function F has ZA and ZT0 state, calls another function G that only shares ZT0 state with its caller, F will have to save ZA before the call to G, and restore it afterwards (rather than setting up a lazy-sve). This is not yet implemented in LLVM and does not result in a compile-time error either. So instead of silently generating incorrect code, it's better to emit an error saying this is not yet implemented. --- .../clang/Basic/DiagnosticSemaKinds.td | 6 +++ clang/lib/Sema/SemaChecking.cpp | 50 +++++++++---------- clang/test/Sema/aarch64-sme-func-attrs.c | 13 ++++- 3 files changed, 40 insertions(+), 29 deletions(-) diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td index 7638a7e84c3c03..21a767cfc5e5c3 100644 --- a/clang/include/clang/Basic/DiagnosticSemaKinds.td +++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td @@ -3711,6 +3711,12 @@ def err_sme_za_call_no_za_state : Error< "call to a shared ZA function requires the caller to have ZA state">; def err_sme_zt0_call_no_zt0_state : Error< "call to a shared ZT0 function requires the caller to have ZT0 state">; +def err_sme_unimplemented_za_save_restore : Error< + "call to a function that shares state other than 'za' from a " + "function that has live 'za' state requires a spill/fill of ZA, which is not yet " + "implemented">; +def note_sme_use_preserves_za : Note< + "add '__arm_preserves(\"za\")' to the callee if it preserves ZA">; def err_sme_definition_using_sm_in_non_sme_target : Error< "function executed in streaming-SVE mode requires 'sme'">; def err_sme_definition_using_za_in_non_sme_target : Error< diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp index 7b877da1a928f6..b071a02ca3713f 100644 --- a/clang/lib/Sema/SemaChecking.cpp +++ b/clang/lib/Sema/SemaChecking.cpp @@ -7513,47 +7513,43 @@ void Sema::checkCall(NamedDecl *FDecl, const FunctionProtoType *Proto, } } - // If the callee uses AArch64 SME ZA state but the caller doesn't define - // any, then this is an error. - FunctionType::ArmStateValue ArmZAState = + FunctionType::ArmStateValue CalleeArmZAState = FunctionType::getArmZAState(ExtInfo.AArch64SMEAttributes); - if (ArmZAState != FunctionType::ARM_None) { + FunctionType::ArmStateValue CalleeArmZT0State = + FunctionType::getArmZT0State(ExtInfo.AArch64SMEAttributes); + if (CalleeArmZAState != FunctionType::ARM_None || + CalleeArmZT0State != FunctionType::ARM_None) { bool CallerHasZAState = false; + bool CallerHasZT0State = false; if (const auto *CallerFD = dyn_cast(CurContext)) { auto *Attr = CallerFD->getAttr(); if (Attr && Attr->isNewZA()) CallerHasZAState = true; - else if (const auto *FPT = - CallerFD->getType()->getAs()) - CallerHasZAState = FunctionType::getArmZAState( - FPT->getExtProtoInfo().AArch64SMEAttributes) != - FunctionType::ARM_None; - } - - if (!CallerHasZAState) - Diag(Loc, diag::err_sme_za_call_no_za_state); - } - - // If the callee uses AArch64 SME ZT0 state but the caller doesn't define - // any, then this is an error. - FunctionType::ArmStateValue ArmZT0State = - FunctionType::getArmZT0State(ExtInfo.AArch64SMEAttributes); - if (ArmZT0State != FunctionType::ARM_None) { - bool CallerHasZT0State = false; - if (const auto *CallerFD = dyn_cast(CurContext)) { - auto *Attr = CallerFD->getAttr(); if (Attr && Attr->isNewZT0()) CallerHasZT0State = true; - else if (const auto *FPT = - CallerFD->getType()->getAs()) - CallerHasZT0State = + if (const auto *FPT = CallerFD->getType()->getAs()) { + CallerHasZAState |= + FunctionType::getArmZAState( + FPT->getExtProtoInfo().AArch64SMEAttributes) != + FunctionType::ARM_None; + CallerHasZT0State |= FunctionType::getArmZT0State( FPT->getExtProtoInfo().AArch64SMEAttributes) != FunctionType::ARM_None; + } } - if (!CallerHasZT0State) + if (CalleeArmZAState != FunctionType::ARM_None && !CallerHasZAState) + Diag(Loc, diag::err_sme_za_call_no_za_state); + + if (CalleeArmZT0State != FunctionType::ARM_None && !CallerHasZT0State) Diag(Loc, diag::err_sme_zt0_call_no_zt0_state); + + if (CallerHasZAState && CalleeArmZAState == FunctionType::ARM_None && + CalleeArmZT0State != FunctionType::ARM_None) { + Diag(Loc, diag::err_sme_unimplemented_za_save_restore); + Diag(Loc, diag::note_sme_use_preserves_za); + } } } diff --git a/clang/test/Sema/aarch64-sme-func-attrs.c b/clang/test/Sema/aarch64-sme-func-attrs.c index 97409ae7d6040c..2bf1886951f1f7 100644 --- a/clang/test/Sema/aarch64-sme-func-attrs.c +++ b/clang/test/Sema/aarch64-sme-func-attrs.c @@ -1,5 +1,5 @@ -// RUN: %clang_cc1 -triple aarch64-none-linux-gnu -target-feature +sme -fsyntax-only -verify %s -// RUN: %clang_cc1 -triple aarch64-none-linux-gnu -target-feature +sme -fsyntax-only -verify=expected-cpp -x c++ %s +// RUN: %clang_cc1 -triple aarch64-none-linux-gnu -target-feature +sme2 -fsyntax-only -verify %s +// RUN: %clang_cc1 -triple aarch64-none-linux-gnu -target-feature +sme2 -fsyntax-only -verify=expected-cpp -x c++ %s // Valid attributes @@ -445,3 +445,12 @@ void conflicting_state_attrs_preserves_out_zt0(void) __arm_preserves("zt0") __ar // expected-cpp-error@+2 {{conflicting attributes for state 'zt0'}} // expected-error@+1 {{conflicting attributes for state 'zt0'}} void conflicting_state_attrs_preserves_inout_zt0(void) __arm_preserves("zt0") __arm_inout("zt0"); + +// Test that we get a diagnostic for unimplemented case. +void unimplemented_spill_fill_za(void (*share_zt0_only)(void) __arm_inout("zt0")) __arm_inout("za", "zt0") { + // expected-cpp-error@+4 {{call to a function that shares state other than 'za' from a function that has live 'za' state requires a spill/fill of ZA, which is not yet implemented}} + // expected-cpp-note@+3 {{add '__arm_preserves("za")' to the callee if it preserves ZA}} + // expected-error@+2 {{call to a function that shares state other than 'za' from a function that has live 'za' state requires a spill/fill of ZA, which is not yet implemented}} + // expected-note@+1 {{add '__arm_preserves("za")' to the callee if it preserves ZA}} + share_zt0_only(); +}