[OpenACC] Implement enter data/exit data construct parsing (#72916)

These two constructs, 'enter data' and 'exit data', are novel compared
to what is currently in the parser, as this is the first set implemented
where the first token is itself not a valid construct. Because of this,
it requires some additional work to do the first keyword parsing.

Author: erichkeane

clang/include/clang/Basic/DiagnosticParseKinds.td

@@ -1362,7 +1362,7 @@ def warn_pragma_acc_unimplemented_clause_parsing
     : Warning<"OpenACC clause parsing not yet implemented">,
       InGroup<SourceUsesOpenACC>;
 def err_acc_invalid_directive
-    : Error<"invalid OpenACC directive '%0'">;
+    : Error<"invalid OpenACC directive '%select{%1|%1 %2}0'">;
 def err_acc_missing_directive : Error<"expected OpenACC directive">;
 
 // OpenMP support.

clang/include/clang/Basic/OpenACCKinds.h

@@ -24,9 +24,12 @@ enum class OpenACCDirectiveKind {
   Serial,
   Kernels,
 
-  // Data Environment.
+  // Data Environment. "enter data" and "exit data" are also referred to in the
+  // Executable Directives section, but just as a back reference to the Data
+  // Environment.
   Data,
-  // FIXME: 'enter data', 'exit data'.
+  EnterData,
+  ExitData,
   HostData,
 
   // Misc.

clang/lib/Parse/ParseOpenACC.cpp

@@ -21,24 +21,45 @@ using namespace clang;
 using namespace llvm;
 
 namespace {
-
-/// This doesn't completely comprehend 'Compound Constructs' (as it just
-/// identifies the first token) just the first token of each.  So
-/// this should only be used by `ParseOpenACCDirectiveKind`.
-OpenACCDirectiveKind getOpenACCDirectiveKind(StringRef Name) {
-  return llvm::StringSwitch<OpenACCDirectiveKind>(Name)
-      .Case("parallel", OpenACCDirectiveKind::Parallel)
-      .Case("serial", OpenACCDirectiveKind::Serial)
-      .Case("kernels", OpenACCDirectiveKind::Kernels)
-      .Case("data", OpenACCDirectiveKind::Data)
-      .Case("host_data", OpenACCDirectiveKind::HostData)
-      .Case("loop", OpenACCDirectiveKind::Loop)
-      .Case("declare", OpenACCDirectiveKind::Declare)
-      .Case("init", OpenACCDirectiveKind::Init)
-      .Case("shutdown", OpenACCDirectiveKind::Shutdown)
-      .Case("set", OpenACCDirectiveKind::Shutdown)
-      .Case("update", OpenACCDirectiveKind::Update)
-      .Default(OpenACCDirectiveKind::Invalid);
+// An enum that contains the extended 'partial' parsed variants. This type
+// should never escape the initial parse functionality, but is useful for
+// simplifying the implementation.
+enum class OpenACCDirectiveKindEx {
+  Invalid = static_cast<int>(OpenACCDirectiveKind::Invalid),
+  // 'enter data' and 'exit data'
+  Enter,
+  Exit,
+  // FIXME: Atomic Variants
+};
+
+// Translate single-token string representations to the OpenACC Directive Kind.
+// This doesn't completely comprehend 'Compound Constructs' (as it just
+// identifies the first token), and doesn't fully handle 'enter data', 'exit
+// data', nor any of the 'atomic' variants, just the first token of each.  So
+// this should only be used by `ParseOpenACCDirectiveKind`.
+OpenACCDirectiveKindEx getOpenACCDirectiveKind(StringRef Name) {
+  OpenACCDirectiveKind DirKind =
+      llvm::StringSwitch<OpenACCDirectiveKind>(Name)
+          .Case("parallel", OpenACCDirectiveKind::Parallel)
+          .Case("serial", OpenACCDirectiveKind::Serial)
+          .Case("kernels", OpenACCDirectiveKind::Kernels)
+          .Case("data", OpenACCDirectiveKind::Data)
+          .Case("host_data", OpenACCDirectiveKind::HostData)
+          .Case("loop", OpenACCDirectiveKind::Loop)
+          .Case("declare", OpenACCDirectiveKind::Declare)
+          .Case("init", OpenACCDirectiveKind::Init)
+          .Case("shutdown", OpenACCDirectiveKind::Shutdown)
+          .Case("set", OpenACCDirectiveKind::Shutdown)
+          .Case("update", OpenACCDirectiveKind::Update)
+          .Default(OpenACCDirectiveKind::Invalid);
+
+  if (DirKind != OpenACCDirectiveKind::Invalid)
+    return static_cast<OpenACCDirectiveKindEx>(DirKind);
+
+  return llvm::StringSwitch<OpenACCDirectiveKindEx>(Name)
+      .Case("enter", OpenACCDirectiveKindEx::Enter)
+      .Case("exit", OpenACCDirectiveKindEx::Exit)
+      .Default(OpenACCDirectiveKindEx::Invalid);
 }
 
 bool isOpenACCDirectiveKind(OpenACCDirectiveKind Kind, StringRef Tok) {
@@ -59,6 +80,8 @@ bool isOpenACCDirectiveKind(OpenACCDirectiveKind Kind, StringRef Tok) {
   case OpenACCDirectiveKind::ParallelLoop:
   case OpenACCDirectiveKind::SerialLoop:
   case OpenACCDirectiveKind::KernelsLoop:
+  case OpenACCDirectiveKind::EnterData:
+  case OpenACCDirectiveKind::ExitData:
     return false;
 
   case OpenACCDirectiveKind::Declare:
@@ -77,6 +100,32 @@ bool isOpenACCDirectiveKind(OpenACCDirectiveKind Kind, StringRef Tok) {
   llvm_unreachable("Unknown 'Kind' Passed");
 }
 
+OpenACCDirectiveKind
+ParseOpenACCEnterExitDataDirective(Parser &P, Token FirstTok,
+                                   StringRef FirstTokSpelling,
+                                   OpenACCDirectiveKindEx ExtDirKind) {
+  Token SecondTok = P.getCurToken();
+
+  if (SecondTok.isAnnotation()) {
+    P.Diag(FirstTok, diag::err_acc_invalid_directive) << 0 << FirstTokSpelling;
+    return OpenACCDirectiveKind::Invalid;
+  }
+
+  std::string SecondTokSpelling = P.getPreprocessor().getSpelling(SecondTok);
+
+  if (!isOpenACCDirectiveKind(OpenACCDirectiveKind::Data, SecondTokSpelling)) {
+    P.Diag(FirstTok, diag::err_acc_invalid_directive)
+        << 1 << FirstTokSpelling << SecondTokSpelling;
+    return OpenACCDirectiveKind::Invalid;
+  }
+
+  P.ConsumeToken();
+
+  return ExtDirKind == OpenACCDirectiveKindEx::Enter
+             ? OpenACCDirectiveKind::EnterData
+             : OpenACCDirectiveKind::ExitData;
+}
+
 // Parse and consume the tokens for OpenACC Directive/Construct kinds.
 OpenACCDirectiveKind ParseOpenACCDirectiveKind(Parser &P) {
   Token FirstTok = P.getCurToken();
@@ -91,10 +140,28 @@ OpenACCDirectiveKind ParseOpenACCDirectiveKind(Parser &P) {
   P.ConsumeToken();
   std::string FirstTokSpelling = P.getPreprocessor().getSpelling(FirstTok);
 
-  OpenACCDirectiveKind DirKind = getOpenACCDirectiveKind(FirstTokSpelling);
+  OpenACCDirectiveKindEx ExDirKind = getOpenACCDirectiveKind(FirstTokSpelling);
+
+  // OpenACCDirectiveKindEx is meant to be an extended list
+  // over OpenACCDirectiveKind, so any value below Invalid is one of the
+  // OpenACCDirectiveKind values.  This switch takes care of all of the extra
+  // parsing required for the Extended values.  At the end of this block,
+  // ExDirKind can be assumed to be a valid OpenACCDirectiveKind, so we can
+  // immediately cast it and use it as that.
+  if (ExDirKind >= OpenACCDirectiveKindEx::Invalid) {
+    switch (ExDirKind) {
+    case OpenACCDirectiveKindEx::Invalid:
+      P.Diag(FirstTok, diag::err_acc_invalid_directive)
+          << 0 << FirstTokSpelling;
+      return OpenACCDirectiveKind::Invalid;
+    case OpenACCDirectiveKindEx::Enter:
+    case OpenACCDirectiveKindEx::Exit:
+      return ParseOpenACCEnterExitDataDirective(P, FirstTok, FirstTokSpelling,
+                                                ExDirKind);
+    }
+  }
 
-  if (DirKind == OpenACCDirectiveKind::Invalid)
-    P.Diag(FirstTok, diag::err_acc_invalid_directive) << FirstTokSpelling;
+  OpenACCDirectiveKind DirKind = static_cast<OpenACCDirectiveKind>(ExDirKind);
 
   // Combined Constructs allows parallel loop, serial loop, or kernels loop. Any
   // other attempt at a combined construct will be diagnosed as an invalid

clang/test/ParserOpenACC/parse-constructs.c

@@ -34,6 +34,33 @@ void func() {
   for(;;){}
   // expected-warning@+2{{OpenACC clause parsing not yet implemented}}
   // expected-warning@+1{{OpenACC directives not yet implemented, pragma ignored}}
+#pragma acc enter data clause list
+  for(;;){}
+  // expected-warning@+2{{OpenACC clause parsing not yet implemented}}
+  // expected-warning@+1{{OpenACC directives not yet implemented, pragma ignored}}
+#pragma acc exit data clause list
+  for(;;){}
+  // expected-error@+3{{invalid OpenACC directive 'enter invalid'}}
+  // expected-warning@+2{{OpenACC clause parsing not yet implemented}}
+  // expected-warning@+1{{OpenACC directives not yet implemented, pragma ignored}}
+#pragma acc enter invalid
+  for(;;){}
+  // expected-error@+3{{invalid OpenACC directive 'exit invalid'}}
+  // expected-warning@+2{{OpenACC clause parsing not yet implemented}}
+  // expected-warning@+1{{OpenACC directives not yet implemented, pragma ignored}}
+#pragma acc exit invalid
+  for(;;){}
+  // expected-error@+2{{invalid OpenACC directive 'enter'}}
+  // expected-warning@+1{{OpenACC directives not yet implemented, pragma ignored}}
+#pragma acc enter
+  for(;;){}
+  // expected-error@+3{{invalid OpenACC directive 'exit }'}}
+  // expected-warning@+2{{OpenACC clause parsing not yet implemented}}
+  // expected-warning@+1{{OpenACC directives not yet implemented, pragma ignored}}
+#pragma acc exit }
+  for(;;){}
+  // expected-warning@+2{{OpenACC clause parsing not yet implemented}}
+  // expected-warning@+1{{OpenACC directives not yet implemented, pragma ignored}}
 #pragma acc host_data clause list
   for(;;){}
   // expected-warning@+2{{OpenACC clause parsing not yet implemented}}