From 8d4cb852856631543aa961a6149b9a22021a1573 Mon Sep 17 00:00:00 2001 From: Andrew Kelley Date: Thu, 8 Aug 2019 12:30:22 -0400 Subject: async functions in single threaded mode do not use atomic ops --- src/codegen.cpp | 34 +++++++++++++++++++++++++++++----- 1 file changed, 29 insertions(+), 5 deletions(-) (limited to 'src/codegen.cpp') diff --git a/src/codegen.cpp b/src/codegen.cpp index 3c1b7543dc..4ef81de4a0 100644 --- a/src/codegen.cpp +++ b/src/codegen.cpp @@ -2236,6 +2236,29 @@ static LLVMBasicBlockRef gen_suspend_begin(CodeGen *g, const char *name_hint) { return resume_bb; } +static LLVMValueRef gen_maybe_atomic_op(CodeGen *g, LLVMAtomicRMWBinOp op, LLVMValueRef ptr, LLVMValueRef val, + LLVMAtomicOrdering order) +{ + if (g->is_single_threaded) { + LLVMValueRef loaded = LLVMBuildLoad(g->builder, ptr, ""); + LLVMValueRef modified; + switch (op) { + case LLVMAtomicRMWBinOpXchg: + modified = val; + break; + case LLVMAtomicRMWBinOpXor: + modified = LLVMBuildXor(g->builder, loaded, val, ""); + break; + default: + zig_unreachable(); + } + LLVMBuildStore(g->builder, modified, ptr); + return loaded; + } else { + return LLVMBuildAtomicRMW(g->builder, op, ptr, val, order, false); + } +} + static LLVMValueRef ir_render_return_begin(CodeGen *g, IrExecutable *executable, IrInstructionReturnBegin *instruction) { @@ -2259,8 +2282,8 @@ static LLVMValueRef ir_render_return_begin(CodeGen *g, IrExecutable *executable, LLVMValueRef zero = LLVMConstNull(usize_type_ref); LLVMValueRef all_ones = LLVMConstAllOnes(usize_type_ref); - LLVMValueRef prev_val = LLVMBuildAtomicRMW(g->builder, LLVMAtomicRMWBinOpXor, g->cur_async_awaiter_ptr, - all_ones, LLVMAtomicOrderingAcquire, g->is_single_threaded); + LLVMValueRef prev_val = gen_maybe_atomic_op(g, LLVMAtomicRMWBinOpXor, g->cur_async_awaiter_ptr, + all_ones, LLVMAtomicOrderingAcquire); LLVMBasicBlockRef bad_return_block = LLVMAppendBasicBlock(g->cur_fn_val, "BadReturn"); LLVMBasicBlockRef early_return_block = LLVMAppendBasicBlock(g->cur_fn_val, "EarlyReturn"); @@ -5278,7 +5301,8 @@ static LLVMValueRef ir_render_atomic_rmw(CodeGen *g, IrExecutable *executable, LLVMValueRef casted_ptr = LLVMBuildBitCast(g->builder, ptr, LLVMPointerType(g->builtin_types.entry_usize->llvm_type, 0), ""); LLVMValueRef casted_operand = LLVMBuildPtrToInt(g->builder, operand, g->builtin_types.entry_usize->llvm_type, ""); - LLVMValueRef uncasted_result = LLVMBuildAtomicRMW(g->builder, op, casted_ptr, casted_operand, ordering, false); + LLVMValueRef uncasted_result = LLVMBuildAtomicRMW(g->builder, op, casted_ptr, casted_operand, ordering, + g->is_single_threaded); return LLVMBuildIntToPtr(g->builder, uncasted_result, get_llvm_type(g, operand_type), ""); } @@ -5441,8 +5465,8 @@ static LLVMValueRef ir_render_cancel(CodeGen *g, IrExecutable *executable, IrIns LLVMValueRef awaiter_ored_val = LLVMBuildOr(g->builder, awaiter_val, one, ""); LLVMValueRef awaiter_ptr = LLVMBuildStructGEP(g->builder, target_frame_ptr, coro_awaiter_index, ""); - LLVMValueRef prev_val = LLVMBuildAtomicRMW(g->builder, LLVMAtomicRMWBinOpXchg, awaiter_ptr, awaiter_ored_val, - LLVMAtomicOrderingRelease, g->is_single_threaded); + LLVMValueRef prev_val = gen_maybe_atomic_op(g, LLVMAtomicRMWBinOpXchg, awaiter_ptr, awaiter_ored_val, + LLVMAtomicOrderingRelease); LLVMBasicBlockRef complete_suspend_block = LLVMAppendBasicBlock(g->cur_fn_val, "CancelSuspend"); LLVMBasicBlockRef early_return_block = LLVMAppendBasicBlock(g->cur_fn_val, "EarlyReturn"); -- cgit v1.2.3