1 //===- PGOCtxProfWriter.cpp - Contextual Instrumentation profile writer ---===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // Write a contextual profile to bitstream. 10 // 11 //===----------------------------------------------------------------------===// 12 13 #include "llvm/ProfileData/PGOCtxProfWriter.h" 14 #include "llvm/Bitstream/BitCodeEnums.h" 15 16 using namespace llvm; 17 using namespace llvm::ctx_profile; 18 19 void PGOCtxProfileWriter::writeCounters(const ContextNode &Node) { 20 Writer.EmitCode(bitc::UNABBREV_RECORD); 21 Writer.EmitVBR(PGOCtxProfileRecords::Counters, VBREncodingBits); 22 Writer.EmitVBR(Node.counters_size(), VBREncodingBits); 23 for (uint32_t I = 0U; I < Node.counters_size(); ++I) 24 Writer.EmitVBR64(Node.counters()[I], VBREncodingBits); 25 } 26 27 // recursively write all the subcontexts. We do need to traverse depth first to 28 // model the context->subcontext implicitly, and since this captures call 29 // stacks, we don't really need to be worried about stack overflow and we can 30 // keep the implementation simple. 31 void PGOCtxProfileWriter::writeImpl(std::optional<uint32_t> CallerIndex, 32 const ContextNode &Node) { 33 Writer.EnterSubblock(PGOCtxProfileBlockIDs::ContextNodeBlockID, CodeLen); 34 Writer.EmitRecord(PGOCtxProfileRecords::Guid, 35 SmallVector<uint64_t, 1>{Node.guid()}); 36 if (CallerIndex) 37 Writer.EmitRecord(PGOCtxProfileRecords::CalleeIndex, 38 SmallVector<uint64_t, 1>{*CallerIndex}); 39 writeCounters(Node); 40 for (uint32_t I = 0U; I < Node.callsites_size(); ++I) 41 for (const auto *Subcontext = Node.subContexts()[I]; Subcontext; 42 Subcontext = Subcontext->next()) 43 writeImpl(I, *Subcontext); 44 Writer.ExitBlock(); 45 } 46 47 void PGOCtxProfileWriter::write(const ContextNode &RootNode) { 48 writeImpl(std::nullopt, RootNode); 49 } 50