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/Module.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     const DISubprogram *SP = InlinedAt->getScope()->getSubprogram();
  34     // Use linkage name for C++ if possible.
  35     auto Name = SP->getLinkageName();
  36     if (Name.empty())
  37       Name = SP->getName();
  38     uint64_t CallerGuid = Function::getGUID(Name);
  39     uint64_t CallerProbeId = PseudoProbeDwarfDiscriminator::extractProbeIndex(
  40         InlinedAt->getDiscriminator());
  41     ReversedInlineStack.emplace_back(CallerGuid, CallerProbeId);
  42     InlinedAt = InlinedAt->getInlinedAt();
  43   }
  44
  45   SmallVector<InlineSite, 8> InlineStack(ReversedInlineStack.rbegin(),
  46                                          ReversedInlineStack.rend());
  47   Asm->OutStreamer->emitPseudoProbe(Guid, Index, Type, Attr, InlineStack);
  48 }