llvm/lib/Target/NVPTX/NVPTXAssignValidGlobalNames.cpp

   1 //===-- NVPTXAssignValidGlobalNames.cpp - Assign valid names to globals ---===//
   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 // Clean up the names of global variables in the module to not contain symbols
  10 // that are invalid in PTX.
  11 //
  12 // Currently NVPTX, like other backends, relies on generic symbol name
  13 // sanitizing done by MC. However, the ptxas assembler is more stringent and
  14 // disallows some additional characters in symbol names. This pass makes sure
  15 // such names do not reach MC at all.
  16 //
  17 //===----------------------------------------------------------------------===//
  18
  19 #include "NVPTX.h"
  20 #include "llvm/ADT/StringExtras.h"
  21 #include "llvm/IR/Function.h"
  22 #include "llvm/IR/GlobalVariable.h"
  23 #include "llvm/IR/LegacyPassManager.h"
  24 #include "llvm/IR/Module.h"
  25 #include "llvm/Support/raw_ostream.h"
  26 #include <string>
  27
  28 using namespace llvm;
  29
  30 namespace {
  31 /// NVPTXAssignValidGlobalNames
  32 class NVPTXAssignValidGlobalNames : public ModulePass {
  33 public:
  34   static char ID;
  35   NVPTXAssignValidGlobalNames() : ModulePass(ID) {}
  36
  37   bool runOnModule(Module &M) override;
  38
  39   /// Clean up the name to remove symbols invalid in PTX.
  40   std::string cleanUpName(StringRef Name);
  41 };
  42 }
  43
  44 char NVPTXAssignValidGlobalNames::ID = 0;
  45
  46 namespace llvm {
  47 void initializeNVPTXAssignValidGlobalNamesPass(PassRegistry &);
  48 }
  49
  50 INITIALIZE_PASS(NVPTXAssignValidGlobalNames, "nvptx-assign-valid-global-names",
  51                 "Assign valid PTX names to globals", false, false)
  52
  53 bool NVPTXAssignValidGlobalNames::runOnModule(Module &M) {
  54   for (GlobalVariable &GV : M.globals()) {
  55     // We are only allowed to rename local symbols.
  56     if (GV.hasLocalLinkage()) {
  57       // setName doesn't do extra work if the name does not change.
  58       // Note: this does not create collisions - if setName is asked to set the
  59       // name to something that already exists, it adds a proper postfix to
  60       // avoid collisions.
  61       GV.setName(cleanUpName(GV.getName()));
  62     }
  63   }
  64
  65   // Do the same for local functions.
  66   for (Function &F : M.functions())
  67     if (F.hasLocalLinkage())
  68       F.setName(cleanUpName(F.getName()));
  69
  70   return true;
  71 }
  72
  73 std::string NVPTXAssignValidGlobalNames::cleanUpName(StringRef Name) {
  74   std::string ValidName;
  75   raw_string_ostream ValidNameStream(ValidName);
  76   for (char C : Name) {
  77     // While PTX also allows '%' at the start of identifiers, LLVM will throw a
  78     // fatal error for '%' in symbol names in MCSymbol::print. Exclude for now.
  79     if (isAlnum(C) || C == '_' || C == '$') {
  80       ValidNameStream << C;
  81     } else {
  82       ValidNameStream << "_$_";
  83     }
  84   }
  85
  86   return ValidNameStream.str();
  87 }
  88
  89 ModulePass *llvm::createNVPTXAssignValidGlobalNamesPass() {
  90   return new NVPTXAssignValidGlobalNames();
  91 }