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 void PseudoProbeHandler::emitPseudoProbe(uint64_t Guid, uint64_t Index, 24 uint64_t Type, uint64_t Attr, 25 const DILocation *DebugLoc) { 26 // Gather all the inlined-at nodes. 27 // When it's done ReversedInlineStack looks like ([66, B], [88, A]) 28 // which means, Function A inlines function B at calliste with a probe id 88, 29 // and B inlines C at probe 66 where C is represented by Guid. 30 SmallVector<InlineSite, 8> ReversedInlineStack; 31 auto *InlinedAt = DebugLoc ? DebugLoc->getInlinedAt() : nullptr; 32 while (InlinedAt) { 33 auto Name = InlinedAt->getSubprogramLinkageName(); 34 // Use caching to avoid redundant md5 computation for build speed. 35 uint64_t &CallerGuid = NameGuidMap[Name]; 36 if (!CallerGuid) 37 CallerGuid = Function::getGUID(Name); 38 uint64_t CallerProbeId = PseudoProbeDwarfDiscriminator::extractProbeIndex( 39 InlinedAt->getDiscriminator()); 40 ReversedInlineStack.emplace_back(CallerGuid, CallerProbeId); 41 InlinedAt = InlinedAt->getInlinedAt(); 42 } 43 uint64_t Discriminator = 0; 44 // For now only block probes have FS discriminators. See 45 // MIRFSDiscriminator.cpp for more details. 46 if (EnableFSDiscriminator && DebugLoc && 47 (Type == (uint64_t)PseudoProbeType::Block)) 48 Discriminator = DebugLoc->getDiscriminator(); 49 assert((EnableFSDiscriminator || Discriminator == 0) && 50 "Discriminator should not be set in non-FSAFDO mode"); 51 SmallVector<InlineSite, 8> InlineStack(llvm::reverse(ReversedInlineStack)); 52 Asm->OutStreamer->emitPseudoProbe(Guid, Index, Type, Attr, Discriminator, 53 InlineStack, Asm->CurrentFnSym); 54 } 55