1 //===- ValueSymbolTable.cpp - Implement the ValueSymbolTable class --------===//
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 // This file implements the ValueSymbolTable class for the IR library.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "llvm/IR/ValueSymbolTable.h"
14 #include "llvm/ADT/SmallString.h"
15 #include "llvm/ADT/Triple.h"
16 #include "llvm/Config/llvm-config.h"
17 #include "llvm/IR/GlobalValue.h"
18 #include "llvm/IR/Module.h"
19 #include "llvm/IR/Type.h"
20 #include "llvm/IR/Value.h"
21 #include "llvm/Support/Casting.h"
22 #include "llvm/Support/Compiler.h"
23 #include "llvm/Support/Debug.h"
24 #include "llvm/Support/raw_ostream.h"
25 #include <cassert>
26 #include <utility>
27 
28 using namespace llvm;
29 
30 #define DEBUG_TYPE "valuesymtab"
31 
32 // Class destructor
33 ValueSymbolTable::~ValueSymbolTable() {
34 #ifndef NDEBUG // Only do this in -g mode...
35   for (const auto &VI : vmap)
36     dbgs() << "Value still in symbol table! Type = '"
37            << *VI.getValue()->getType() << "' Name = '" << VI.getKeyData()
38            << "'\n";
39   assert(vmap.empty() && "Values remain in symbol table!");
40 #endif
41 }
42 
43 ValueName *ValueSymbolTable::makeUniqueName(Value *V,
44                                             SmallString<256> &UniqueName) {
45   unsigned BaseSize = UniqueName.size();
46   while (true) {
47     // Trim any suffix off and append the next number.
48     UniqueName.resize(BaseSize);
49     raw_svector_ostream S(UniqueName);
50     if (auto *GV = dyn_cast<GlobalValue>(V)) {
51       // A dot is appended to mark it as clone during ABI demangling so that
52       // for example "_Z1fv" and "_Z1fv.1" both demangle to "f()", the second
53       // one being a clone.
54       // On NVPTX we cannot use a dot because PTX only allows [A-Za-z0-9_$] for
55       // identifiers. This breaks ABI demangling but at least ptxas accepts and
56       // compiles the program.
57       const Module *M = GV->getParent();
58       if (!(M && Triple(M->getTargetTriple()).isNVPTX()))
59         S << ".";
60     }
61     S << ++LastUnique;
62 
63     // Try insert the vmap entry with this suffix.
64     auto IterBool = vmap.insert(std::make_pair(UniqueName.str(), V));
65     if (IterBool.second)
66       return &*IterBool.first;
67   }
68 }
69 
70 // Insert a value into the symbol table with the specified name...
71 //
72 void ValueSymbolTable::reinsertValue(Value *V) {
73   assert(V->hasName() && "Can't insert nameless Value into symbol table");
74 
75   // Try inserting the name, assuming it won't conflict.
76   if (vmap.insert(V->getValueName())) {
77     // LLVM_DEBUG(dbgs() << " Inserted value: " << V->getValueName() << ": " <<
78     // *V << "\n");
79     return;
80   }
81 
82   // Otherwise, there is a naming conflict.  Rename this value.
83   SmallString<256> UniqueName(V->getName().begin(), V->getName().end());
84 
85   // The name is too already used, just free it so we can allocate a new name.
86   MallocAllocator Allocator;
87   V->getValueName()->Destroy(Allocator);
88 
89   ValueName *VN = makeUniqueName(V, UniqueName);
90   V->setValueName(VN);
91 }
92 
93 void ValueSymbolTable::removeValueName(ValueName *V) {
94   // LLVM_DEBUG(dbgs() << " Removing Value: " << V->getKeyData() << "\n");
95   // Remove the value from the symbol table.
96   vmap.remove(V);
97 }
98 
99 /// createValueName - This method attempts to create a value name and insert
100 /// it into the symbol table with the specified name.  If it conflicts, it
101 /// auto-renames the name and returns that instead.
102 ValueName *ValueSymbolTable::createValueName(StringRef Name, Value *V) {
103   if (MaxNameSize > -1 && Name.size() > (unsigned)MaxNameSize)
104     Name = Name.substr(0, std::max(1u, (unsigned)MaxNameSize));
105 
106   // In the common case, the name is not already in the symbol table.
107   auto IterBool = vmap.insert(std::make_pair(Name, V));
108   if (IterBool.second) {
109     // LLVM_DEBUG(dbgs() << " Inserted value: " << Entry.getKeyData() << ": "
110     //           << *V << "\n");
111     return &*IterBool.first;
112   }
113 
114   // Otherwise, there is a naming conflict.  Rename this value.
115   SmallString<256> UniqueName(Name.begin(), Name.end());
116   return makeUniqueName(V, UniqueName);
117 }
118 
119 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
120 // dump - print out the symbol table
121 //
122 LLVM_DUMP_METHOD void ValueSymbolTable::dump() const {
123   // dbgs() << "ValueSymbolTable:\n";
124   for (const auto &I : *this) {
125     // dbgs() << "  '" << I->getKeyData() << "' = ";
126     I.getValue()->dump();
127     // dbgs() << "\n";
128   }
129 }
130 #endif
131