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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;
NVPTXAssignValidGlobalNames()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 
runOnModule(Module & M)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 
cleanUpName(StringRef Name)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 
createNVPTXAssignValidGlobalNamesPass()82 ModulePass *llvm::createNVPTXAssignValidGlobalNamesPass() {
83   return new NVPTXAssignValidGlobalNames();
84 }
85