1//===- AMDGPUExportKernelRuntimeHandles.cpp - Lower enqueued block --------===//
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// \file
10//
11// Give any globals used for OpenCL block enqueue runtime handles external
12// linkage so the runtime may access them. These should behave like internal
13// functions for purposes of linking, but need to have an external symbol in the
14// final object for the runtime to access them.
15//
16// TODO: This could be replaced with a new linkage type or global object
17// metadata that produces an external symbol in the final object, but allows
18// rename on IR linking. Alternatively if we can rely on
19// GlobalValue::getGlobalIdentifier we can just make these external symbols to
20// begin with.
21//
22//===----------------------------------------------------------------------===//
23
24#include "AMDGPUExportKernelRuntimeHandles.h"
25#include "AMDGPU.h"
26#include "llvm/IR/Module.h"
27#include "llvm/Pass.h"
28
29#define DEBUG_TYPE "amdgpu-export-kernel-runtime-handles"
30
31using namespace llvm;
32
33namespace {
34
35/// Lower enqueued blocks.
36class AMDGPUExportKernelRuntimeHandlesLegacy : public ModulePass {
37public:
38 static char ID;
39
40 explicit AMDGPUExportKernelRuntimeHandlesLegacy() : ModulePass(ID) {}
41
42private:
43 bool runOnModule(Module &M) override;
44};
45
46} // end anonymous namespace
47
48char AMDGPUExportKernelRuntimeHandlesLegacy::ID = 0;
49
50char &llvm::AMDGPUExportKernelRuntimeHandlesLegacyID =
51 AMDGPUExportKernelRuntimeHandlesLegacy::ID;
52
53INITIALIZE_PASS(AMDGPUExportKernelRuntimeHandlesLegacy, DEBUG_TYPE,
54 "Externalize enqueued block runtime handles", false, false)
55
56ModulePass *llvm::createAMDGPUExportKernelRuntimeHandlesLegacyPass() {
57 return new AMDGPUExportKernelRuntimeHandlesLegacy();
58}
59
60static bool exportKernelRuntimeHandles(Module &M) {
61 bool Changed = false;
62
63 const StringLiteral HandleSectionName(".amdgpu.kernel.runtime.handle");
64
65 for (GlobalVariable &GV : M.globals()) {
66 if (GV.getSection() == HandleSectionName) {
67 GV.setLinkage(GlobalValue::ExternalLinkage);
68 GV.setDSOLocal(false);
69 Changed = true;
70 }
71 }
72
73 if (!Changed)
74 return false;
75
76 // FIXME: We shouldn't really need to export the kernel address. We can
77 // initialize the runtime handle with the kernel descriptor.
78 for (Function &F : M) {
79 if (F.getCallingConv() != CallingConv::AMDGPU_KERNEL)
80 continue;
81
82 const MDNode *Associated = F.getMetadata(KindID: LLVMContext::MD_associated);
83 if (!Associated)
84 continue;
85
86 auto *VM = cast<ValueAsMetadata>(Val: Associated->getOperand(I: 0));
87 auto *Handle = dyn_cast<GlobalObject>(Val: VM->getValue());
88 if (Handle && Handle->getSection() == HandleSectionName) {
89 F.setLinkage(GlobalValue::ExternalLinkage);
90 F.setVisibility(GlobalValue::ProtectedVisibility);
91 }
92 }
93
94 return Changed;
95}
96
97bool AMDGPUExportKernelRuntimeHandlesLegacy::runOnModule(Module &M) {
98 return exportKernelRuntimeHandles(M);
99}
100
101PreservedAnalyses
102AMDGPUExportKernelRuntimeHandlesPass::run(Module &M,
103 ModuleAnalysisManager &MAM) {
104 if (!exportKernelRuntimeHandles(M))
105 return PreservedAnalyses::all();
106
107 PreservedAnalyses PA;
108 PA.preserveSet<AllAnalysesOn<Function>>();
109 return PA;
110}
111