1 //===--- SIMDIntrinsicsCheck.cpp - clang-tidy------------------------------===//
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 "SIMDIntrinsicsCheck.h"
10 #include "clang/AST/ASTContext.h"
11 #include "clang/ASTMatchers/ASTMatchFinder.h"
12 #include "clang/Basic/TargetInfo.h"
13 #include "llvm/ADT/StringMap.h"
14 #include "llvm/Support/ManagedStatic.h"
15 #include "llvm/Support/Regex.h"
16 #include "llvm/TargetParser/Triple.h"
17
18 using namespace clang::ast_matchers;
19
20 namespace clang::tidy::portability {
21
22 namespace {
23
24 // If the callee has parameter of VectorType or pointer to VectorType,
25 // or the return type is VectorType, we consider it a vector function
26 // and a candidate for checking.
AST_MATCHER(FunctionDecl,isVectorFunction)27 AST_MATCHER(FunctionDecl, isVectorFunction) {
28 bool IsVector = Node.getReturnType()->isVectorType();
29 for (const ParmVarDecl *Parm : Node.parameters()) {
30 QualType Type = Parm->getType();
31 if (Type->isPointerType())
32 Type = Type->getPointeeType();
33 if (Type->isVectorType())
34 IsVector = true;
35 }
36 return IsVector;
37 }
38
39 } // namespace
40
trySuggestPpc(StringRef Name)41 static StringRef trySuggestPpc(StringRef Name) {
42 if (!Name.consume_front("vec_"))
43 return {};
44
45 return llvm::StringSwitch<StringRef>(Name)
46 // [simd.alg]
47 .Case("max", "$std::max")
48 .Case("min", "$std::min")
49 // [simd.binary]
50 .Case("add", "operator+ on $simd objects")
51 .Case("sub", "operator- on $simd objects")
52 .Case("mul", "operator* on $simd objects")
53 .Default({});
54 }
55
trySuggestX86(StringRef Name)56 static StringRef trySuggestX86(StringRef Name) {
57 if (!(Name.consume_front("_mm_") || Name.consume_front("_mm256_") ||
58 Name.consume_front("_mm512_")))
59 return {};
60
61 // [simd.alg]
62 if (Name.starts_with("max_"))
63 return "$simd::max";
64 if (Name.starts_with("min_"))
65 return "$simd::min";
66
67 // [simd.binary]
68 if (Name.starts_with("add_"))
69 return "operator+ on $simd objects";
70 if (Name.starts_with("sub_"))
71 return "operator- on $simd objects";
72 if (Name.starts_with("mul_"))
73 return "operator* on $simd objects";
74
75 return {};
76 }
77
SIMDIntrinsicsCheck(StringRef Name,ClangTidyContext * Context)78 SIMDIntrinsicsCheck::SIMDIntrinsicsCheck(StringRef Name,
79 ClangTidyContext *Context)
80 : ClangTidyCheck(Name, Context), Std(Options.get("Std", "")),
81 Suggest(Options.get("Suggest", false)) {}
82
storeOptions(ClangTidyOptions::OptionMap & Opts)83 void SIMDIntrinsicsCheck::storeOptions(ClangTidyOptions::OptionMap &Opts) {
84 Options.store(Opts, "Std", Std);
85 Options.store(Opts, "Suggest", Suggest);
86 }
87
registerMatchers(MatchFinder * Finder)88 void SIMDIntrinsicsCheck::registerMatchers(MatchFinder *Finder) {
89 // If Std is not specified, infer it from the language options.
90 // libcxx implementation backports it to C++11 std::experimental::simd.
91 if (Std.empty())
92 Std = getLangOpts().CPlusPlus20 ? "std" : "std::experimental";
93
94 Finder->addMatcher(callExpr(callee(functionDecl(
95 matchesName("^::(_mm_|_mm256_|_mm512_|vec_)"),
96 isVectorFunction())),
97 unless(isExpansionInSystemHeader()))
98 .bind("call"),
99 this);
100 }
101
check(const MatchFinder::MatchResult & Result)102 void SIMDIntrinsicsCheck::check(const MatchFinder::MatchResult &Result) {
103 const auto *Call = Result.Nodes.getNodeAs<CallExpr>("call");
104 assert(Call != nullptr);
105 const FunctionDecl *Callee = Call->getDirectCallee();
106 if (!Callee)
107 return;
108
109 StringRef Old = Callee->getName();
110 StringRef New;
111 llvm::Triple::ArchType Arch =
112 Result.Context->getTargetInfo().getTriple().getArch();
113
114 // We warn or suggest if this SIMD intrinsic function has a std::simd
115 // replacement.
116 switch (Arch) {
117 default:
118 break;
119 case llvm::Triple::ppc:
120 case llvm::Triple::ppc64:
121 case llvm::Triple::ppc64le:
122 New = trySuggestPpc(Old);
123 break;
124 case llvm::Triple::x86:
125 case llvm::Triple::x86_64:
126 New = trySuggestX86(Old);
127 break;
128 }
129
130 // We have found a std::simd replacement.
131 if (!New.empty()) {
132 // If Suggest is true, give a P0214 alternative, otherwise point it out it
133 // is non-portable.
134 if (Suggest) {
135 static const llvm::Regex StdRegex("\\$std"), SimdRegex("\\$simd");
136 diag(Call->getExprLoc(), "'%0' can be replaced by %1")
137 << Old
138 << SimdRegex.sub(SmallString<32>({Std, "::simd"}),
139 StdRegex.sub(Std, New));
140 } else {
141 diag(Call->getExprLoc(), "'%0' is a non-portable %1 intrinsic function")
142 << Old << llvm::Triple::getArchTypeName(Arch);
143 }
144 }
145 }
146
147 } // namespace clang::tidy::portability
148