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      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, 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   // In the common case, the name is not already in the symbol table.
    104   auto IterBool = vmap.insert(std::make_pair(Name, V));
    105   if (IterBool.second) {
    106     // LLVM_DEBUG(dbgs() << " Inserted value: " << Entry.getKeyData() << ": "
    107     //           << *V << "\n");
    108     return &*IterBool.first;
    109   }
    110 
    111   // Otherwise, there is a naming conflict.  Rename this value.
    112   SmallString<256> UniqueName(Name.begin(), Name.end());
    113   return makeUniqueName(V, UniqueName);
    114 }
    115 
    116 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
    117 // dump - print out the symbol table
    118 //
    119 LLVM_DUMP_METHOD void ValueSymbolTable::dump() const {
    120   // dbgs() << "ValueSymbolTable:\n";
    121   for (const auto &I : *this) {
    122     // dbgs() << "  '" << I->getKeyData() << "' = ";
    123     I.getValue()->dump();
    124     // dbgs() << "\n";
    125   }
    126 }
    127 #endif
    128