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
21using namespace llvm;
22
23void 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::getGUIDAssumingExternalLinkage(GlobalName: Name);
38 uint64_t CallerProbeId = PseudoProbeDwarfDiscriminator::extractProbeIndex(
39 Value: InlinedAt->getDiscriminator());
40 ReversedInlineStack.emplace_back(Args&: CallerGuid, Args&: 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(C&: ReversedInlineStack));
52 Asm->OutStreamer->emitPseudoProbe(Guid, Index, Type, Attr, Discriminator,
53 InlineStack, FnSym: Asm->CurrentFnSym);
54}
55