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/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;
NVPTXAssignValidGlobalNames()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 
runOnModule(Module & M)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 
cleanUpName(StringRef Name)73 std::string NVPTXAssignValidGlobalNames::cleanUpName(StringRef Name) {
74   std::string ValidName;
75   raw_string_ostream ValidNameStream(ValidName);
76   for (unsigned I = 0, E = Name.size(); I != E; ++I) {
77     char C = Name[I];
78     if (C == '.' || C == '@') {
79       ValidNameStream << "_$_";
80     } else {
81       ValidNameStream << C;
82     }
83   }
84 
85   return ValidNameStream.str();
86 }
87 
createNVPTXAssignValidGlobalNamesPass()88 ModulePass *llvm::createNVPTXAssignValidGlobalNamesPass() {
89   return new NVPTXAssignValidGlobalNames();
90 }
91