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
27using namespace llvm;
28
29namespace {
30/// NVPTXAssignValidGlobalNames
31class NVPTXAssignValidGlobalNames : public ModulePass {
32public:
33  static char ID;
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
43char NVPTXAssignValidGlobalNames::ID = 0;
44
45namespace llvm {
46void initializeNVPTXAssignValidGlobalNamesPass(PassRegistry &);
47}
48
49INITIALIZE_PASS(NVPTXAssignValidGlobalNames, "nvptx-assign-valid-global-names",
50                "Assign valid PTX names to globals", false, false)
51
52bool 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
72std::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
87ModulePass *llvm::createNVPTXAssignValidGlobalNamesPass() {
88  return new NVPTXAssignValidGlobalNames();
89}
90