xref: /llvm-project/clang-tools-extra/clang-tidy/altera/SingleWorkItemBarrierCheck.cpp (revision df0c8f25145047731fb95b4ce7153ce6fb5b6f5d)
1 //===--- SingleWorkItemBarrierCheck.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 "SingleWorkItemBarrierCheck.h"
10 #include "clang/AST/ASTContext.h"
11 #include "clang/ASTMatchers/ASTMatchFinder.h"
12 
13 using namespace clang::ast_matchers;
14 
15 namespace clang::tidy::altera {
16 
registerMatchers(MatchFinder * Finder)17 void SingleWorkItemBarrierCheck::registerMatchers(MatchFinder *Finder) {
18   // Find any function that calls barrier but does not call an ID function.
19   // hasAttr(attr::Kind::OpenCLKernel) restricts it to only kernel functions.
20   // FIXME: Have it accept all functions but check for a parameter that gets an
21   // ID from one of the four ID functions.
22   Finder->addMatcher(
23       // Find function declarations...
24       functionDecl(
25           // That are OpenCL kernels...
26           hasAttr(attr::Kind::OpenCLKernel),
27           // And call a barrier function (either 1.x or 2.x version)...
28           forEachDescendant(callExpr(callee(functionDecl(hasAnyName(
29                                          "barrier", "work_group_barrier"))))
30                                 .bind("barrier")),
31           // But do not call an ID function.
32           unless(hasDescendant(callExpr(callee(functionDecl(
33               hasAnyName("get_global_id", "get_local_id", "get_group_id",
34                          "get_local_linear_id")))))))
35           .bind("function"),
36       this);
37 }
38 
check(const MatchFinder::MatchResult & Result)39 void SingleWorkItemBarrierCheck::check(const MatchFinder::MatchResult &Result) {
40   const auto *MatchedDecl = Result.Nodes.getNodeAs<FunctionDecl>("function");
41   const auto *MatchedBarrier = Result.Nodes.getNodeAs<CallExpr>("barrier");
42   if (AOCVersion < 1701) {
43     // get_group_id and get_local_linear_id were added at/after v17.01
44     diag(MatchedDecl->getLocation(),
45          "kernel function %0 does not call 'get_global_id' or 'get_local_id' "
46          "and will be treated as a single work-item")
47         << MatchedDecl;
48     diag(MatchedBarrier->getBeginLoc(),
49          "barrier call is in a single work-item and may error out",
50          DiagnosticIDs::Note);
51   } else {
52     // If reqd_work_group_size is anything other than (1,1,1), it will be
53     // interpreted as an NDRange in AOC version >= 17.1.
54     bool IsNDRange = false;
55     if (MatchedDecl->hasAttr<ReqdWorkGroupSizeAttr>()) {
56       const auto *Attribute = MatchedDecl->getAttr<ReqdWorkGroupSizeAttr>();
57       if (Attribute->getXDim() > 1 || Attribute->getYDim() > 1 ||
58           Attribute->getZDim() > 1)
59         IsNDRange = true;
60     }
61     if (IsNDRange) // No warning if kernel is treated as an NDRange.
62       return;
63     diag(MatchedDecl->getLocation(),
64          "kernel function %0 does not call an ID function and may be a viable "
65          "single work-item, but will be forced to execute as an NDRange")
66         << MatchedDecl;
67     diag(MatchedBarrier->getBeginLoc(),
68          "barrier call will force NDRange execution; if single work-item "
69          "semantics are desired a mem_fence may be more efficient",
70          DiagnosticIDs::Note);
71   }
72 }
73 
storeOptions(ClangTidyOptions::OptionMap & Opts)74 void SingleWorkItemBarrierCheck::storeOptions(
75     ClangTidyOptions::OptionMap &Opts) {
76   Options.store(Opts, "AOCVersion", AOCVersion);
77 }
78 
79 } // namespace clang::tidy::altera
80