[clang-tidy] Link targets and Asm parsers

[zturner]

Summary

Currently clang-tidy fails on any file that includes inline assembly. This is not a great out-of-the-box experience since many system headers include inline assembly, particularly on Windows.

I checked through the various other clang tools and they all have similar logic to link in a minimal amount of backend stuff to get a target registry, so this patch does the same for clang-tidy

[alexfh]

The first attempt to fix this (https://reviews.llvm.org/D17981) was stuck on figuring out whether we care about the binary size. It seems to me that the binary size is secondary to maintaining proper functionality for platforms that use inline assembly in headers. Thus, LG

[alexfh]

Zachary, do you plan to commit this? I'd also suggest adding a regression test.

Thanks!

[zturner]

Added a test. Alex, if you can confirm this test gives sufficient coverage I can go ahead and submit today. Thanks!

[alexfh]

clang-tools-extra/test/clang-tidy/hicpp-no-assembler.cpp

13–16

Will this compile on linux and mac? If no, maybe a separate test just for windows is the way to go.

[alexfh]

clang-tools-extra/test/clang-tidy/hicpp-no-assembler.cpp

13–16

... answering my own question: no, it doesn't compile on linux (https://godbolt.org/g/9HVvjp).

Please add a separate test guarded by REQUIRES: system-windows and ensure it breaks before your patch and passes with it.

clang-tools-extra/clang-tidy/CMakeLists.txt

 set(LLVM_LINK_COMPONENTS
+  AllTargetsAsmParsers
+  AllTargetsInfos
   Support
   )
 
 add_clang_library(clangTidy
   ClangTidy.cpp
   ClangTidyModule.cpp
   ClangTidyDiagnosticConsumer.cpp
   ClangTidyOptions.cpp

clang-tools-extra/clang-tidy/tool/ClangTidyMain.cpp

 ///    http://clang.llvm.org/docs/HowToSetupToolingForLLVM.html
 ///  for details on setting it up with LLVM source tree.
 ///
 //===----------------------------------------------------------------------===//
 
 #include "../ClangTidy.h"
 #include "clang/Tooling/CommonOptionsParser.h"
 #include "llvm/Support/Process.h"
+#include "llvm/Support/TargetSelect.h"
 
 using namespace clang::ast_matchers;
 using namespace clang::driver;
 using namespace clang::tooling;
 using namespace llvm;
 
 static cl::OptionCategory ClangTidyCategory("clang-tidy options");
 
static int clangTidyMain(int argc, const char **argv) {
   if (PathList.empty()) {
     llvm::errs() << "Error: no input files specified.\n";
     llvm::cl::PrintHelpMessage(/*Hidden=*/false, /*Categorized=*/true);
     return 0;
   }
 
   ProfileData Profile;
 
+  llvm::InitializeAllTargetInfos();
+  llvm::InitializeAllTargetMCs();
+  llvm::InitializeAllAsmParsers();
+
   ClangTidyContext Context(std::move(OwningOptionsProvider));
   runClangTidy(Context, OptionsParser.getCompilations(), PathList,
                EnableCheckProfile ? &Profile : nullptr);
   ArrayRef<ClangTidyError> Errors = Context.getErrors();
   bool FoundErrors =
       std::find_if(Errors.begin(), Errors.end(), [](const ClangTidyError &E) {
         return E.DiagLevel == ClangTidyError::Error;
       }) != Errors.end();

clang-tools-extra/test/clang-tidy/hicpp-no-assembler.cpp

 // RUN: %check_clang_tidy %s hicpp-no-assembler %t
 
 __asm__(".symver foo, bar@v");
 // CHECK-MESSAGES: :[[@LINE-1]]:1: warning: do not use inline assembler in safety-critical code [hicpp-no-assembler]
 
 static int s asm("spam");
 // CHECK-MESSAGES: :[[@LINE-1]]:12: warning: do not use inline assembler in safety-critical code [hicpp-no-assembler]
 
 void f() {
   __asm("mov al, 2");
   // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: do not use inline assembler in safety-critical code [hicpp-no-assembler]
+
+  _asm {
+    mov al, 2;
+    // CHECK-MESSAGES: :[[@LINE-2]]:3: warning: do not use inline assembler in safety-critical code [hicpp-no-assembler]
+  }
 }