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
|
//===-- XCoreLowerThreadLocal - Lower thread local variables --------------===//
//
// 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 file contains a pass that lowers thread local variables on the
/// XCore.
///
//===----------------------------------------------------------------------===//
#include "XCore.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/GlobalVariable.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/Intrinsics.h"
#include "llvm/IR/IntrinsicsXCore.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/NoFolder.h"
#include "llvm/IR/ValueHandle.h"
#include "llvm/Pass.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#define DEBUG_TYPE "xcore-lower-thread-local"
using namespace llvm;
static cl::opt<unsigned> MaxThreads(
"xcore-max-threads", cl::Optional,
cl::desc("Maximum number of threads (for emulation thread-local storage)"),
cl::Hidden, cl::value_desc("number"), cl::init(8));
namespace {
/// Lowers thread local variables on the XCore. Each thread local variable is
/// expanded to an array of n elements indexed by the thread ID where n is the
/// fixed number hardware threads supported by the device.
struct XCoreLowerThreadLocal : public ModulePass {
static char ID;
XCoreLowerThreadLocal() : ModulePass(ID) {
initializeXCoreLowerThreadLocalPass(*PassRegistry::getPassRegistry());
}
bool lowerGlobal(GlobalVariable *GV);
bool runOnModule(Module &M) override;
};
}
char XCoreLowerThreadLocal::ID = 0;
INITIALIZE_PASS(XCoreLowerThreadLocal, "xcore-lower-thread-local",
"Lower thread local variables", false, false)
ModulePass *llvm::createXCoreLowerThreadLocalPass() {
return new XCoreLowerThreadLocal();
}
static ArrayType *createLoweredType(Type *OriginalType) {
return ArrayType::get(OriginalType, MaxThreads);
}
static Constant *
createLoweredInitializer(ArrayType *NewType, Constant *OriginalInitializer) {
SmallVector<Constant *, 8> Elements(MaxThreads);
for (unsigned i = 0; i != MaxThreads; ++i) {
Elements[i] = OriginalInitializer;
}
return ConstantArray::get(NewType, Elements);
}
static bool replaceConstantExprOp(ConstantExpr *CE, Pass *P) {
do {
SmallVector<WeakTrackingVH, 8> WUsers(CE->users());
llvm::sort(WUsers);
WUsers.erase(std::unique(WUsers.begin(), WUsers.end()), WUsers.end());
while (!WUsers.empty())
if (WeakTrackingVH WU = WUsers.pop_back_val()) {
if (PHINode *PN = dyn_cast<PHINode>(WU)) {
for (int I = 0, E = PN->getNumIncomingValues(); I < E; ++I)
if (PN->getIncomingValue(I) == CE) {
BasicBlock *PredBB = PN->getIncomingBlock(I);
if (PredBB->getTerminator()->getNumSuccessors() > 1)
PredBB = SplitEdge(PredBB, PN->getParent());
Instruction *InsertPos = PredBB->getTerminator();
Instruction *NewInst = CE->getAsInstruction(InsertPos);
PN->setOperand(I, NewInst);
}
} else if (Instruction *Instr = dyn_cast<Instruction>(WU)) {
Instruction *NewInst = CE->getAsInstruction(Instr);
Instr->replaceUsesOfWith(CE, NewInst);
} else {
ConstantExpr *CExpr = dyn_cast<ConstantExpr>(WU);
if (!CExpr || !replaceConstantExprOp(CExpr, P))
return false;
}
}
} while (CE->hasNUsesOrMore(1)); // We need to check because a recursive
// sibling may have used 'CE' when getAsInstruction was called.
CE->destroyConstant();
return true;
}
static bool rewriteNonInstructionUses(GlobalVariable *GV, Pass *P) {
SmallVector<WeakTrackingVH, 8> WUsers;
for (User *U : GV->users())
if (!isa<Instruction>(U))
WUsers.push_back(WeakTrackingVH(U));
while (!WUsers.empty())
if (WeakTrackingVH WU = WUsers.pop_back_val()) {
ConstantExpr *CE = dyn_cast<ConstantExpr>(WU);
if (!CE || !replaceConstantExprOp(CE, P))
return false;
}
return true;
}
static bool isZeroLengthArray(Type *Ty) {
ArrayType *AT = dyn_cast<ArrayType>(Ty);
return AT && (AT->getNumElements() == 0);
}
bool XCoreLowerThreadLocal::lowerGlobal(GlobalVariable *GV) {
Module *M = GV->getParent();
if (!GV->isThreadLocal())
return false;
// Skip globals that we can't lower and leave it for the backend to error.
if (!rewriteNonInstructionUses(GV, this) ||
!GV->getType()->isSized() || isZeroLengthArray(GV->getType()))
return false;
// Create replacement global.
ArrayType *NewType = createLoweredType(GV->getValueType());
Constant *NewInitializer = nullptr;
if (GV->hasInitializer())
NewInitializer = createLoweredInitializer(NewType,
GV->getInitializer());
GlobalVariable *NewGV =
new GlobalVariable(*M, NewType, GV->isConstant(), GV->getLinkage(),
NewInitializer, "", nullptr,
GlobalVariable::NotThreadLocal,
GV->getType()->getAddressSpace(),
GV->isExternallyInitialized());
// Update uses.
SmallVector<User *, 16> Users(GV->users());
for (unsigned I = 0, E = Users.size(); I != E; ++I) {
User *U = Users[I];
Instruction *Inst = cast<Instruction>(U);
IRBuilder<> Builder(Inst);
Function *GetID = Intrinsic::getDeclaration(GV->getParent(),
Intrinsic::xcore_getid);
Value *ThreadID = Builder.CreateCall(GetID, {});
Value *Addr = Builder.CreateInBoundsGEP(NewGV->getValueType(), NewGV,
{Builder.getInt64(0), ThreadID});
U->replaceUsesOfWith(GV, Addr);
}
// Remove old global.
NewGV->takeName(GV);
GV->eraseFromParent();
return true;
}
bool XCoreLowerThreadLocal::runOnModule(Module &M) {
// Find thread local globals.
bool MadeChange = false;
SmallVector<GlobalVariable *, 16> ThreadLocalGlobals;
for (GlobalVariable &GV : M.globals())
if (GV.isThreadLocal())
ThreadLocalGlobals.push_back(&GV);
for (unsigned I = 0, E = ThreadLocalGlobals.size(); I != E; ++I) {
MadeChange |= lowerGlobal(ThreadLocalGlobals[I]);
}
return MadeChange;
}
|
