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
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
|
// SPDX-License-Identifier: GPL-2.0
/*
* llvm C frontend for perf. Support dynamically compile C file
*
* Inspired by clang example code:
* http://llvm.org/svn/llvm-project/cfe/trunk/examples/clang-interpreter/main.cpp
*
* Copyright (C) 2016 Wang Nan <wangnan0@huawei.com>
* Copyright (C) 2016 Huawei Inc.
*/
#include "clang/CodeGen/CodeGenAction.h"
#include "clang/Frontend/CompilerInvocation.h"
#include "clang/Frontend/CompilerInstance.h"
#include "clang/Frontend/TextDiagnosticPrinter.h"
#include "clang/Tooling/Tooling.h"
#include "llvm/IR/LegacyPassManager.h"
#include "llvm/IR/Module.h"
#include "llvm/Option/Option.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/ManagedStatic.h"
#include "llvm/Support/TargetRegistry.h"
#include "llvm/Support/TargetSelect.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetOptions.h"
#include <memory>
#include "clang.h"
#include "clang-c.h"
namespace perf {
static std::unique_ptr<llvm::LLVMContext> LLVMCtx;
using namespace clang;
static CompilerInvocation *
createCompilerInvocation(llvm::opt::ArgStringList CFlags, StringRef& Path,
DiagnosticsEngine& Diags)
{
llvm::opt::ArgStringList CCArgs {
"-cc1",
"-triple", "bpf-pc-linux",
"-fsyntax-only",
"-ferror-limit", "19",
"-fmessage-length", "127",
"-O2",
"-nostdsysteminc",
"-nobuiltininc",
"-vectorize-loops",
"-vectorize-slp",
"-Wno-unused-value",
"-Wno-pointer-sign",
"-x", "c"};
CCArgs.append(CFlags.begin(), CFlags.end());
CompilerInvocation *CI = tooling::newInvocation(&Diags, CCArgs);
FrontendOptions& Opts = CI->getFrontendOpts();
Opts.Inputs.clear();
Opts.Inputs.emplace_back(Path, IK_C);
return CI;
}
static std::unique_ptr<llvm::Module>
getModuleFromSource(llvm::opt::ArgStringList CFlags,
StringRef Path, IntrusiveRefCntPtr<vfs::FileSystem> VFS)
{
CompilerInstance Clang;
Clang.createDiagnostics();
Clang.setVirtualFileSystem(&*VFS);
IntrusiveRefCntPtr<CompilerInvocation> CI =
createCompilerInvocation(std::move(CFlags), Path,
Clang.getDiagnostics());
Clang.setInvocation(&*CI);
std::unique_ptr<CodeGenAction> Act(new EmitLLVMOnlyAction(&*LLVMCtx));
if (!Clang.ExecuteAction(*Act))
return std::unique_ptr<llvm::Module>(nullptr);
return Act->takeModule();
}
std::unique_ptr<llvm::Module>
getModuleFromSource(llvm::opt::ArgStringList CFlags,
StringRef Name, StringRef Content)
{
using namespace vfs;
llvm::IntrusiveRefCntPtr<OverlayFileSystem> OverlayFS(
new OverlayFileSystem(getRealFileSystem()));
llvm::IntrusiveRefCntPtr<InMemoryFileSystem> MemFS(
new InMemoryFileSystem(true));
/*
* pushOverlay helps setting working dir for MemFS. Must call
* before addFile.
*/
OverlayFS->pushOverlay(MemFS);
MemFS->addFile(Twine(Name), 0, llvm::MemoryBuffer::getMemBuffer(Content));
return getModuleFromSource(std::move(CFlags), Name, OverlayFS);
}
std::unique_ptr<llvm::Module>
getModuleFromSource(llvm::opt::ArgStringList CFlags, StringRef Path)
{
IntrusiveRefCntPtr<vfs::FileSystem> VFS(vfs::getRealFileSystem());
return getModuleFromSource(std::move(CFlags), Path, VFS);
}
std::unique_ptr<llvm::SmallVectorImpl<char>>
getBPFObjectFromModule(llvm::Module *Module)
{
using namespace llvm;
std::string TargetTriple("bpf-pc-linux");
std::string Error;
const Target* Target = TargetRegistry::lookupTarget(TargetTriple, Error);
if (!Target) {
llvm::errs() << Error;
return std::unique_ptr<llvm::SmallVectorImpl<char>>(nullptr);
}
llvm::TargetOptions Opt;
TargetMachine *TargetMachine =
Target->createTargetMachine(TargetTriple,
"generic", "",
Opt, Reloc::Static);
Module->setDataLayout(TargetMachine->createDataLayout());
Module->setTargetTriple(TargetTriple);
std::unique_ptr<SmallVectorImpl<char>> Buffer(new SmallVector<char, 0>());
raw_svector_ostream ostream(*Buffer);
legacy::PassManager PM;
if (TargetMachine->addPassesToEmitFile(PM, ostream,
TargetMachine::CGFT_ObjectFile)) {
llvm::errs() << "TargetMachine can't emit a file of this type\n";
return std::unique_ptr<llvm::SmallVectorImpl<char>>(nullptr);;
}
PM.run(*Module);
return std::move(Buffer);
}
}
extern "C" {
void perf_clang__init(void)
{
perf::LLVMCtx.reset(new llvm::LLVMContext());
LLVMInitializeBPFTargetInfo();
LLVMInitializeBPFTarget();
LLVMInitializeBPFTargetMC();
LLVMInitializeBPFAsmPrinter();
}
void perf_clang__cleanup(void)
{
perf::LLVMCtx.reset(nullptr);
llvm::llvm_shutdown();
}
int perf_clang__compile_bpf(const char *filename,
void **p_obj_buf,
size_t *p_obj_buf_sz)
{
using namespace perf;
if (!p_obj_buf || !p_obj_buf_sz)
return -EINVAL;
llvm::opt::ArgStringList CFlags;
auto M = getModuleFromSource(std::move(CFlags), filename);
if (!M)
return -EINVAL;
auto O = getBPFObjectFromModule(&*M);
if (!O)
return -EINVAL;
size_t size = O->size_in_bytes();
void *buffer;
buffer = malloc(size);
if (!buffer)
return -ENOMEM;
memcpy(buffer, O->data(), size);
*p_obj_buf = buffer;
*p_obj_buf_sz = size;
return 0;
}
}
|
