1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
|
//===- AMDGPUOpenCLEnqueuedBlockLowering.cpp - Lower enqueued block -------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// \file
// This post-linking pass replaces the function pointer of enqueued
// block kernel with a global variable (runtime handle) and adds
// "runtime-handle" attribute to the enqueued block kernel.
//
// In LLVM CodeGen the runtime-handle metadata will be translated to
// RuntimeHandle metadata in code object. Runtime allocates a global buffer
// for each kernel with RuntimeHandle metadata and saves the kernel address
// required for the AQL packet into the buffer. __enqueue_kernel function
// in device library knows that the invoke function pointer in the block
// literal is actually runtime handle and loads the kernel address from it
// and put it into AQL packet for dispatching.
//
// This cannot be done in FE since FE cannot create a unique global variable
// with external linkage across LLVM modules. The global variable with internal
// linkage does not work since optimization passes will try to replace loads
// of the global variable with its initialization value.
//
// It also identifies the kernels directly or indirectly enqueues kernels
// and adds "calls-enqueue-kernel" function attribute to them, which will
// be used to determine whether to emit runtime metadata for the kernel
// enqueue related hidden kernel arguments.
//
//===----------------------------------------------------------------------===//
#include "AMDGPU.h"
#include "llvm/ADT/DenseSet.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/Mangler.h"
#include "llvm/IR/Module.h"
#include "llvm/Pass.h"
#include "llvm/Support/Debug.h"
#define DEBUG_TYPE "amdgpu-lower-enqueued-block"
using namespace llvm;
namespace {
/// Lower enqueued blocks.
class AMDGPUOpenCLEnqueuedBlockLowering : public ModulePass {
public:
static char ID;
explicit AMDGPUOpenCLEnqueuedBlockLowering() : ModulePass(ID) {}
private:
bool runOnModule(Module &M) override;
};
} // end anonymous namespace
char AMDGPUOpenCLEnqueuedBlockLowering::ID = 0;
char &llvm::AMDGPUOpenCLEnqueuedBlockLoweringID =
AMDGPUOpenCLEnqueuedBlockLowering::ID;
INITIALIZE_PASS(AMDGPUOpenCLEnqueuedBlockLowering, DEBUG_TYPE,
"Lower OpenCL enqueued blocks", false, false)
ModulePass* llvm::createAMDGPUOpenCLEnqueuedBlockLoweringPass() {
return new AMDGPUOpenCLEnqueuedBlockLowering();
}
bool AMDGPUOpenCLEnqueuedBlockLowering::runOnModule(Module &M) {
DenseSet<Function *> Callers;
auto &C = M.getContext();
bool Changed = false;
// ptr kernel_object, i32 private_segment_size, i32 group_segment_size
StructType *HandleTy = nullptr;
for (auto &F : M.functions()) {
if (F.hasFnAttribute("enqueued-block")) {
if (!F.hasName()) {
SmallString<64> Name;
Mangler::getNameWithPrefix(Name, "__amdgpu_enqueued_kernel",
M.getDataLayout());
F.setName(Name);
}
LLVM_DEBUG(dbgs() << "found enqueued kernel: " << F.getName() << '\n');
auto RuntimeHandle = (F.getName() + ".runtime_handle").str();
if (!HandleTy) {
Type *Int32 = Type::getInt32Ty(C);
HandleTy = StructType::create(
C, {Type::getInt8Ty(C)->getPointerTo(0), Int32, Int32},
"block.runtime.handle.t");
}
auto *GV = new GlobalVariable(
M, HandleTy,
/*isConstant=*/true, GlobalValue::ExternalLinkage,
/*Initializer=*/Constant::getNullValue(HandleTy), RuntimeHandle,
/*InsertBefore=*/nullptr, GlobalValue::NotThreadLocal,
AMDGPUAS::GLOBAL_ADDRESS,
/*isExternallyInitialized=*/true);
LLVM_DEBUG(dbgs() << "runtime handle created: " << *GV << '\n');
F.replaceAllUsesWith(ConstantExpr::getAddrSpaceCast(GV, F.getType()));
F.addFnAttr("runtime-handle", RuntimeHandle);
F.setLinkage(GlobalValue::ExternalLinkage);
Changed = true;
}
}
return Changed;
}
|
