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comparison lib/Transforms/IPO/ConstantMerge.cpp @ 80:67baa08a3894

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update to LLVM 3.6
author Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
date Thu, 25 Sep 2014 16:56:18 +0900
parents 54457678186b
children afa8332a0e37
comparison
equal deleted inserted replaced
76:9e74acfe8c42 80:67baa08a3894
15 // Algorithm: ConstantMerge is designed to build up a map of available constants 15 // Algorithm: ConstantMerge is designed to build up a map of available constants
16 // and eliminate duplicates when it is initialized. 16 // and eliminate duplicates when it is initialized.
17 // 17 //
18 //===----------------------------------------------------------------------===// 18 //===----------------------------------------------------------------------===//
19 19
20 #define DEBUG_TYPE "constmerge"
21 #include "llvm/Transforms/IPO.h" 20 #include "llvm/Transforms/IPO.h"
22 #include "llvm/ADT/DenseMap.h" 21 #include "llvm/ADT/DenseMap.h"
23 #include "llvm/ADT/PointerIntPair.h" 22 #include "llvm/ADT/PointerIntPair.h"
24 #include "llvm/ADT/SmallPtrSet.h" 23 #include "llvm/ADT/SmallPtrSet.h"
25 #include "llvm/ADT/Statistic.h" 24 #include "llvm/ADT/Statistic.h"
29 #include "llvm/IR/Module.h" 28 #include "llvm/IR/Module.h"
30 #include "llvm/IR/Operator.h" 29 #include "llvm/IR/Operator.h"
31 #include "llvm/Pass.h" 30 #include "llvm/Pass.h"
32 using namespace llvm; 31 using namespace llvm;
33 32
33 #define DEBUG_TYPE "constmerge"
34
34 STATISTIC(NumMerged, "Number of global constants merged"); 35 STATISTIC(NumMerged, "Number of global constants merged");
35 36
36 namespace { 37 namespace {
37 struct ConstantMerge : public ModulePass { 38 struct ConstantMerge : public ModulePass {
38 static char ID; // Pass identification, replacement for typeid 39 static char ID; // Pass identification, replacement for typeid
40 initializeConstantMergePass(*PassRegistry::getPassRegistry()); 41 initializeConstantMergePass(*PassRegistry::getPassRegistry());
41 } 42 }
42 43
43 // For this pass, process all of the globals in the module, eliminating 44 // For this pass, process all of the globals in the module, eliminating
44 // duplicate constants. 45 // duplicate constants.
45 bool runOnModule(Module &M); 46 bool runOnModule(Module &M) override;
46 47
47 // Return true iff we can determine the alignment of this global variable. 48 // Return true iff we can determine the alignment of this global variable.
48 bool hasKnownAlignment(GlobalVariable *GV) const; 49 bool hasKnownAlignment(GlobalVariable *GV) const;
49 50
50 // Return the alignment of the global, including converting the default 51 // Return the alignment of the global, including converting the default
51 // alignment to a concrete value. 52 // alignment to a concrete value.
52 unsigned getAlignment(GlobalVariable *GV) const; 53 unsigned getAlignment(GlobalVariable *GV) const;
53 54
54 const DataLayout *TD; 55 const DataLayout *DL;
55 }; 56 };
56 } 57 }
57 58
58 char ConstantMerge::ID = 0; 59 char ConstantMerge::ID = 0;
59 INITIALIZE_PASS(ConstantMerge, "constmerge", 60 INITIALIZE_PASS(ConstantMerge, "constmerge",
63 64
64 65
65 66
66 /// Find values that are marked as llvm.used. 67 /// Find values that are marked as llvm.used.
67 static void FindUsedValues(GlobalVariable *LLVMUsed, 68 static void FindUsedValues(GlobalVariable *LLVMUsed,
68 SmallPtrSet<const GlobalValue*, 8> &UsedValues) { 69 SmallPtrSetImpl<const GlobalValue*> &UsedValues) {
69 if (LLVMUsed == 0) return; 70 if (!LLVMUsed) return;
70 ConstantArray *Inits = cast<ConstantArray>(LLVMUsed->getInitializer()); 71 ConstantArray *Inits = cast<ConstantArray>(LLVMUsed->getInitializer());
71 72
72 for (unsigned i = 0, e = Inits->getNumOperands(); i != e; ++i) { 73 for (unsigned i = 0, e = Inits->getNumOperands(); i != e; ++i) {
73 Value *Operand = Inits->getOperand(i)->stripPointerCastsNoFollowAliases(); 74 Value *Operand = Inits->getOperand(i)->stripPointerCastsNoFollowAliases();
74 GlobalValue *GV = cast<GlobalValue>(Operand); 75 GlobalValue *GV = cast<GlobalValue>(Operand);
75 UsedValues.insert(GV); 76 UsedValues.insert(GV);
76 } 77 }
77 } 78 }
78 79
79 // True if A is better than B. 80 // True if A is better than B.
80 static bool IsBetterCannonical(const GlobalVariable &A, 81 static bool IsBetterCanonical(const GlobalVariable &A,
81 const GlobalVariable &B) { 82 const GlobalVariable &B) {
82 if (!A.hasLocalLinkage() && B.hasLocalLinkage()) 83 if (!A.hasLocalLinkage() && B.hasLocalLinkage())
83 return true; 84 return true;
84 85
85 if (A.hasLocalLinkage() && !B.hasLocalLinkage()) 86 if (A.hasLocalLinkage() && !B.hasLocalLinkage())
86 return false; 87 return false;
87 88
88 return A.hasUnnamedAddr(); 89 return A.hasUnnamedAddr();
89 } 90 }
90 91
91 bool ConstantMerge::hasKnownAlignment(GlobalVariable *GV) const { 92 bool ConstantMerge::hasKnownAlignment(GlobalVariable *GV) const {
92 return TD || GV->getAlignment() != 0; 93 return DL || GV->getAlignment() != 0;
93 } 94 }
94 95
95 unsigned ConstantMerge::getAlignment(GlobalVariable *GV) const { 96 unsigned ConstantMerge::getAlignment(GlobalVariable *GV) const {
96 unsigned Align = GV->getAlignment(); 97 unsigned Align = GV->getAlignment();
97 if (Align) 98 if (Align)
98 return Align; 99 return Align;
99 if (TD) 100 if (DL)
100 return TD->getPreferredAlignment(GV); 101 return DL->getPreferredAlignment(GV);
101 return 0; 102 return 0;
102 } 103 }
103 104
104 bool ConstantMerge::runOnModule(Module &M) { 105 bool ConstantMerge::runOnModule(Module &M) {
105 TD = getAnalysisIfAvailable<DataLayout>(); 106 DataLayoutPass *DLP = getAnalysisIfAvailable<DataLayoutPass>();
107 DL = DLP ? &DLP->getDataLayout() : nullptr;
106 108
107 // Find all the globals that are marked "used". These cannot be merged. 109 // Find all the globals that are marked "used". These cannot be merged.
108 SmallPtrSet<const GlobalValue*, 8> UsedGlobals; 110 SmallPtrSet<const GlobalValue*, 8> UsedGlobals;
109 FindUsedValues(M.getGlobalVariable("llvm.used"), UsedGlobals); 111 FindUsedValues(M.getGlobalVariable("llvm.used"), UsedGlobals);
110 FindUsedValues(M.getGlobalVariable("llvm.compiler.used"), UsedGlobals); 112 FindUsedValues(M.getGlobalVariable("llvm.compiler.used"), UsedGlobals);
158 GlobalVariable *&Slot = CMap[Pair]; 160 GlobalVariable *&Slot = CMap[Pair];
159 161
160 // If this is the first constant we find or if the old one is local, 162 // If this is the first constant we find or if the old one is local,
161 // replace with the current one. If the current is externally visible 163 // replace with the current one. If the current is externally visible
162 // it cannot be replace, but can be the canonical constant we merge with. 164 // it cannot be replace, but can be the canonical constant we merge with.
163 if (Slot == 0 || IsBetterCannonical(*GV, *Slot)) 165 if (!Slot || IsBetterCanonical(*GV, *Slot))
164 Slot = GV; 166 Slot = GV;
165 } 167 }
166 168
167 // Second: identify all globals that can be merged together, filling in 169 // Second: identify all globals that can be merged together, filling in
168 // the Replacements vector. We cannot do the replacement in this pass 170 // the Replacements vector. We cannot do the replacement in this pass