llvm/lib/IR/ValueSymbolTable.cpp

   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/Config/llvm-config.h"
  16 #include "llvm/IR/GlobalValue.h"
  17 #include "llvm/IR/Module.h"
  18 #include "llvm/IR/Type.h"
  19 #include "llvm/IR/Value.h"
  20 #include "llvm/Support/Casting.h"
  21 #include "llvm/Support/Compiler.h"
  22 #include "llvm/Support/Debug.h"
  23 #include "llvm/Support/raw_ostream.h"
  24 #include "llvm/TargetParser/Triple.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   bool AppenDot = false;
  47   if (auto *GV = dyn_cast<GlobalValue>(V)) {
  48     // A dot is appended to mark it as clone during ABI demangling so that
  49     // for example "_Z1fv" and "_Z1fv.1" both demangle to "f()", the second
  50     // one being a clone.
  51     // On NVPTX we cannot use a dot because PTX only allows [A-Za-z0-9_$] for
  52     // identifiers. This breaks ABI demangling but at least ptxas accepts and
  53     // compiles the program.
  54     const Module *M = GV->getParent();
  55     if (!(M && Triple(M->getTargetTriple()).isNVPTX()))
  56       AppenDot = true;
  57   }
  58
  59   while (true) {
  60     // Trim any suffix off and append the next number.
  61     UniqueName.resize(BaseSize);
  62     raw_svector_ostream S(UniqueName);
  63     if (AppenDot)
  64       S << ".";
  65     S << ++LastUnique;
  66
  67     // Retry if MaxNameSize has been exceeded.
  68     if (MaxNameSize > -1 && UniqueName.size() > (size_t)MaxNameSize) {
  69       assert(BaseSize >= UniqueName.size() - (size_t)MaxNameSize &&
  70              "Can't generate unique name: MaxNameSize is too small.");
  71       BaseSize -= UniqueName.size() - (size_t)MaxNameSize;
  72       continue;
  73     }
  74     // Try insert the vmap entry with this suffix.
  75     auto IterBool = vmap.insert(std::make_pair(UniqueName.str(), V));
  76     if (IterBool.second)
  77       return &*IterBool.first;
  78   }
  79 }
  80
  81 // Insert a value into the symbol table with the specified name...
  82 //
  83 void ValueSymbolTable::reinsertValue(Value *V) {
  84   assert(V->hasName() && "Can't insert nameless Value into symbol table");
  85
  86   // Try inserting the name, assuming it won't conflict.
  87   if (vmap.insert(V->getValueName())) {
  88     // LLVM_DEBUG(dbgs() << " Inserted value: " << V->getValueName() << ": " <<
  89     // *V << "\n");
  90     return;
  91   }
  92
  93   // Otherwise, there is a naming conflict.  Rename this value.
  94   SmallString<256> UniqueName(V->getName().begin(), V->getName().end());
  95
  96   // The name is too already used, just free it so we can allocate a new name.
  97   MallocAllocator Allocator;
  98   V->getValueName()->Destroy(Allocator);
  99
 100   ValueName *VN = makeUniqueName(V, UniqueName);
 101   V->setValueName(VN);
 102 }
 103
 104 void ValueSymbolTable::removeValueName(ValueName *V) {
 105   // LLVM_DEBUG(dbgs() << " Removing Value: " << V->getKeyData() << "\n");
 106   // Remove the value from the symbol table.
 107   vmap.remove(V);
 108 }
 109
 110 /// createValueName - This method attempts to create a value name and insert
 111 /// it into the symbol table with the specified name.  If it conflicts, it
 112 /// auto-renames the name and returns that instead.
 113 ValueName *ValueSymbolTable::createValueName(StringRef Name, Value *V) {
 114   if (MaxNameSize > -1 && Name.size() > (unsigned)MaxNameSize)
 115     Name = Name.substr(0, std::max(1u, (unsigned)MaxNameSize));
 116
 117   // In the common case, the name is not already in the symbol table.
 118   auto IterBool = vmap.insert(std::make_pair(Name, V));
 119   if (IterBool.second) {
 120     // LLVM_DEBUG(dbgs() << " Inserted value: " << Entry.getKeyData() << ": "
 121     //           << *V << "\n");
 122     return &*IterBool.first;
 123   }
 124
 125   // Otherwise, there is a naming conflict.  Rename this value.
 126   SmallString<256> UniqueName(Name.begin(), Name.end());
 127   return makeUniqueName(V, UniqueName);
 128 }
 129
 130 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
 131 // dump - print out the symbol table
 132 //
 133 LLVM_DUMP_METHOD void ValueSymbolTable::dump() const {
 134   // dbgs() << "ValueSymbolTable:\n";
 135   for (const auto &I : *this) {
 136     // dbgs() << "  '" << I->getKeyData() << "' = ";
 137     I.getValue()->dump();
 138     // dbgs() << "\n";
 139   }
 140 }
 141 #endif