ForceFunctionAttrs.cpp revision 360784 
1//===- ForceFunctionAttrs.cpp - Force function attrs for debugging --------===//
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#include "llvm/Transforms/IPO/ForceFunctionAttrs.h"
10#include "llvm/ADT/StringSwitch.h"
11#include "llvm/IR/Function.h"
12#include "llvm/IR/LLVMContext.h"
13#include "llvm/IR/Module.h"
14#include "llvm/InitializePasses.h"
15#include "llvm/Support/CommandLine.h"
16#include "llvm/Support/Debug.h"
17#include "llvm/Support/raw_ostream.h"
18using namespace llvm;
19
20#define DEBUG_TYPE "forceattrs"
21
22static cl::list<std::string>
23    ForceAttributes("force-attribute", cl::Hidden,
24                    cl::desc("Add an attribute to a function. This should be a "
25                             "pair of 'function-name:attribute-name', for "
26                             "example -force-attribute=foo:noinline. This "
27                             "option can be specified multiple times."));
28
29static Attribute::AttrKind parseAttrKind(StringRef Kind) {
30  return StringSwitch<Attribute::AttrKind>(Kind)
31      .Case("alwaysinline", Attribute::AlwaysInline)
32      .Case("builtin", Attribute::Builtin)
33      .Case("cold", Attribute::Cold)
34      .Case("convergent", Attribute::Convergent)
35      .Case("inlinehint", Attribute::InlineHint)
36      .Case("jumptable", Attribute::JumpTable)
37      .Case("minsize", Attribute::MinSize)
38      .Case("naked", Attribute::Naked)
39      .Case("nobuiltin", Attribute::NoBuiltin)
40      .Case("noduplicate", Attribute::NoDuplicate)
41      .Case("noimplicitfloat", Attribute::NoImplicitFloat)
42      .Case("noinline", Attribute::NoInline)
43      .Case("nonlazybind", Attribute::NonLazyBind)
44      .Case("noredzone", Attribute::NoRedZone)
45      .Case("noreturn", Attribute::NoReturn)
46      .Case("nocf_check", Attribute::NoCfCheck)
47      .Case("norecurse", Attribute::NoRecurse)
48      .Case("nounwind", Attribute::NoUnwind)
49      .Case("optforfuzzing", Attribute::OptForFuzzing)
50      .Case("optnone", Attribute::OptimizeNone)
51      .Case("optsize", Attribute::OptimizeForSize)
52      .Case("readnone", Attribute::ReadNone)
53      .Case("readonly", Attribute::ReadOnly)
54      .Case("argmemonly", Attribute::ArgMemOnly)
55      .Case("returns_twice", Attribute::ReturnsTwice)
56      .Case("safestack", Attribute::SafeStack)
57      .Case("shadowcallstack", Attribute::ShadowCallStack)
58      .Case("sanitize_address", Attribute::SanitizeAddress)
59      .Case("sanitize_hwaddress", Attribute::SanitizeHWAddress)
60      .Case("sanitize_memory", Attribute::SanitizeMemory)
61      .Case("sanitize_thread", Attribute::SanitizeThread)
62      .Case("sanitize_memtag", Attribute::SanitizeMemTag)
63      .Case("speculative_load_hardening", Attribute::SpeculativeLoadHardening)
64      .Case("ssp", Attribute::StackProtect)
65      .Case("sspreq", Attribute::StackProtectReq)
66      .Case("sspstrong", Attribute::StackProtectStrong)
67      .Case("strictfp", Attribute::StrictFP)
68      .Case("uwtable", Attribute::UWTable)
69      .Default(Attribute::None);
70}
71
72/// If F has any forced attributes given on the command line, add them.
73static void addForcedAttributes(Function &F) {
74  for (auto &S : ForceAttributes) {
75    auto KV = StringRef(S).split(':');
76    if (KV.first != F.getName())
77      continue;
78
79    auto Kind = parseAttrKind(KV.second);
80    if (Kind == Attribute::None) {
81      LLVM_DEBUG(dbgs() << "ForcedAttribute: " << KV.second
82                        << " unknown or not handled!\n");
83      continue;
84    }
85    if (F.hasFnAttribute(Kind))
86      continue;
87    F.addFnAttr(Kind);
88  }
89}
90
91PreservedAnalyses ForceFunctionAttrsPass::run(Module &M,
92                                              ModuleAnalysisManager &) {
93  if (ForceAttributes.empty())
94    return PreservedAnalyses::all();
95
96  for (Function &F : M.functions())
97    addForcedAttributes(F);
98
99  // Just conservatively invalidate analyses, this isn't likely to be important.
100  return PreservedAnalyses::none();
101}
102
103namespace {
104struct ForceFunctionAttrsLegacyPass : public ModulePass {
105  static char ID; // Pass identification, replacement for typeid
106  ForceFunctionAttrsLegacyPass() : ModulePass(ID) {
107    initializeForceFunctionAttrsLegacyPassPass(
108        *PassRegistry::getPassRegistry());
109  }
110
111  bool runOnModule(Module &M) override {
112    if (ForceAttributes.empty())
113      return false;
114
115    for (Function &F : M.functions())
116      addForcedAttributes(F);
117
118    // Conservatively assume we changed something.
119    return true;
120  }
121};
122}
123
124char ForceFunctionAttrsLegacyPass::ID = 0;
125INITIALIZE_PASS(ForceFunctionAttrsLegacyPass, "forceattrs",
126                "Force set function attributes", false, false)
127
128Pass *llvm::createForceFunctionAttrsLegacyPass() {
129  return new ForceFunctionAttrsLegacyPass();
130}
131