1 //===- llvm/CodeGen/PseudoProbePrinter.cpp - Pseudo Probe Emission -------===// 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 // This file contains support for writing pseudo probe info into asm files. 10 // 11 //===----------------------------------------------------------------------===// 12 13 #include "PseudoProbePrinter.h" 14 #include "llvm/CodeGen/AsmPrinter.h" 15 #include "llvm/IR/DebugInfoMetadata.h" 16 #include "llvm/IR/Function.h" 17 #include "llvm/IR/PseudoProbe.h" 18 #include "llvm/MC/MCPseudoProbe.h" 19 #include "llvm/MC/MCStreamer.h" 20 21 using namespace llvm; 22 23 PseudoProbeHandler::~PseudoProbeHandler() = default; 24 25 void PseudoProbeHandler::emitPseudoProbe(uint64_t Guid, uint64_t Index, 26 uint64_t Type, uint64_t Attr, 27 const DILocation *DebugLoc) { 28 // Gather all the inlined-at nodes. 29 // When it's done ReversedInlineStack looks like ([66, B], [88, A]) 30 // which means, Function A inlines function B at calliste with a probe id 88, 31 // and B inlines C at probe 66 where C is represented by Guid. 32 SmallVector<InlineSite, 8> ReversedInlineStack; 33 auto *InlinedAt = DebugLoc ? DebugLoc->getInlinedAt() : nullptr; 34 while (InlinedAt) { 35 const DISubprogram *SP = InlinedAt->getScope()->getSubprogram(); 36 // Use linkage name for C++ if possible. 37 auto Name = SP->getLinkageName(); 38 if (Name.empty()) 39 Name = SP->getName(); 40 // Use caching to avoid redundant md5 computation for build speed. 41 uint64_t &CallerGuid = NameGuidMap[Name]; 42 if (!CallerGuid) 43 CallerGuid = Function::getGUID(Name); 44 uint64_t CallerProbeId = PseudoProbeDwarfDiscriminator::extractProbeIndex( 45 InlinedAt->getDiscriminator()); 46 ReversedInlineStack.emplace_back(CallerGuid, CallerProbeId); 47 InlinedAt = InlinedAt->getInlinedAt(); 48 } 49 50 SmallVector<InlineSite, 8> InlineStack(llvm::reverse(ReversedInlineStack)); 51 Asm->OutStreamer->emitPseudoProbe(Guid, Index, Type, Attr, InlineStack, 52 Asm->CurrentFnSym); 53 } 54