clang-tools-extra/clang-tidy/altera/SingleWorkItemBarrierCheck.cpp

   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
  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
  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
  74 void SingleWorkItemBarrierCheck::storeOptions(
  75     ClangTidyOptions::OptionMap &Opts) {
  76   Options.store(Opts, "AOCVersion", AOCVersion);
  77 }
  78
  79 } // namespace clang::tidy::altera