llvm/lib/CodeGen/AsmPrinter/PseudoProbePrinter.cpp

   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 }