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 } 92