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      1 //===-- NVPTXAssignValidGlobalNames.cpp - Assign valid names to globals ---===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 //
     10 // Clean up the names of global variables in the module to not contain symbols
     11 // that are invalid in PTX.
     12 //
     13 // Currently NVPTX, like other backends, relies on generic symbol name
     14 // sanitizing done by MC. However, the ptxas assembler is more stringent and
     15 // disallows some additional characters in symbol names. This pass makes sure
     16 // such names do not reach MC at all.
     17 //
     18 //===----------------------------------------------------------------------===//
     19 
     20 #include "NVPTX.h"
     21 #include "llvm/IR/GlobalVariable.h"
     22 #include "llvm/IR/LegacyPassManager.h"
     23 #include "llvm/IR/Module.h"
     24 #include "llvm/Support/raw_ostream.h"
     25 #include <string>
     26 
     27 using namespace llvm;
     28 
     29 namespace {
     30 /// \brief NVPTXAssignValidGlobalNames
     31 class NVPTXAssignValidGlobalNames : public ModulePass {
     32 public:
     33   static char ID;
     34   NVPTXAssignValidGlobalNames() : ModulePass(ID) {}
     35 
     36   bool runOnModule(Module &M) override;
     37 
     38   /// \brief Clean up the name to remove symbols invalid in PTX.
     39   std::string cleanUpName(StringRef Name);
     40 };
     41 }
     42 
     43 char NVPTXAssignValidGlobalNames::ID = 0;
     44 
     45 namespace llvm {
     46 void initializeNVPTXAssignValidGlobalNamesPass(PassRegistry &);
     47 }
     48 
     49 INITIALIZE_PASS(NVPTXAssignValidGlobalNames, "nvptx-assign-valid-global-names",
     50                 "Assign valid PTX names to globals", false, false)
     51 
     52 bool NVPTXAssignValidGlobalNames::runOnModule(Module &M) {
     53   for (GlobalVariable &GV : M.globals()) {
     54     // We are only allowed to rename local symbols.
     55     if (GV.hasLocalLinkage()) {
     56       // setName doesn't do extra work if the name does not change.
     57       // Note: this does not create collisions - if setName is asked to set the
     58       // name to something that already exists, it adds a proper postfix to
     59       // avoid collisions.
     60       GV.setName(cleanUpName(GV.getName()));
     61     }
     62   }
     63 
     64   return true;
     65 }
     66 
     67 std::string NVPTXAssignValidGlobalNames::cleanUpName(StringRef Name) {
     68   std::string ValidName;
     69   raw_string_ostream ValidNameStream(ValidName);
     70   for (unsigned I = 0, E = Name.size(); I != E; ++I) {
     71     char C = Name[I];
     72     if (C == '.' || C == '@') {
     73       ValidNameStream << "_$_";
     74     } else {
     75       ValidNameStream << C;
     76     }
     77   }
     78 
     79   return ValidNameStream.str();
     80 }
     81 
     82 ModulePass *llvm::createNVPTXAssignValidGlobalNamesPass() {
     83   return new NVPTXAssignValidGlobalNames();
     84 }
     85