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/IR/Function.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 /// 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   /// 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   // Do the same for local functions.
65   for (Function &F : M.functions())
66     if (F.hasLocalLinkage())
67       F.setName(cleanUpName(F.getName()));
68 
69   return true;
70 }
71 
cleanUpName(StringRef Name)72 std::string NVPTXAssignValidGlobalNames::cleanUpName(StringRef Name) {
73   std::string ValidName;
74   raw_string_ostream ValidNameStream(ValidName);
75   for (unsigned I = 0, E = Name.size(); I != E; ++I) {
76     char C = Name[I];
77     if (C == '.' || C == '@') {
78       ValidNameStream << "_$_";
79     } else {
80       ValidNameStream << C;
81     }
82   }
83 
84   return ValidNameStream.str();
85 }
86 
createNVPTXAssignValidGlobalNamesPass()87 ModulePass *llvm::createNVPTXAssignValidGlobalNamesPass() {
88   return new NVPTXAssignValidGlobalNames();
89 }
90