Add a state variable to the loop hint attribute.

This patch is necessary to support constant expressions which replaces the integer value in the loop hint attribute with an expression. The integer value was also storing the pragma’s state for options like vectorize(enable/disable) and the pragma unroll and nounroll directive. The state variable is introduced to hold the state of those options/pragmas. This moves the validation of the state (keywords) from SemaStmtAttr handler to the loop hint annotation token handler.

Resubmit with changes to try to fix the build-bot issue.

Reviewed by Aaron Ballman

llvm-svn: 214432

4 files changed, 124 insertions, 106 deletions

diff --git a/clang/lib/CodeGen/CGStmt.cpp b/clang/lib/CodeGen/CGStmt.cpp
index d75b97ddf6a..df30892e869 100644
--- a/clang/lib/CodeGen/CGStmt.cpp
+++ b/clang/lib/CodeGen/CGStmt.cpp
@@ -588,6 +588,7 @@ void CodeGenFunction::EmitCondBrHints(llvm::LLVMContext &Context,
       continue;
 
     LoopHintAttr::OptionType Option = LH->getOption();
+    LoopHintAttr::LoopHintState State = LH->getState();
     int ValueInt = LH->getValue();
 
     const char *MetadataName;
@@ -602,8 +603,8 @@ void CodeGenFunction::EmitCondBrHints(llvm::LLVMContext &Context,
       break;
     case LoopHintAttr::Unroll:
       // With the unroll loop hint, a non-zero value indicates full unrolling.
-      MetadataName =
-          ValueInt == 0 ? "llvm.loop.unroll.disable" : "llvm.loop.unroll.full";
+      MetadataName = State == LoopHintAttr::Disable ? "llvm.loop.unroll.disable"
+                                                    : "llvm.loop.unroll.full";
       break;
     case LoopHintAttr::UnrollCount:
       MetadataName = "llvm.loop.unroll.count";
@@ -614,7 +615,7 @@ void CodeGenFunction::EmitCondBrHints(llvm::LLVMContext &Context,
     switch (Option) {
     case LoopHintAttr::Vectorize:
     case LoopHintAttr::Interleave:
-      if (ValueInt == 1) {
+      if (State != LoopHintAttr::Disable) {
         // FIXME: In the future I will modifiy the behavior of the metadata
         // so we can enable/disable vectorization and interleaving separately.
         Name = llvm::MDString::get(Context, "llvm.loop.vectorize.enable");
diff --git a/clang/lib/Parse/ParsePragma.cpp b/clang/lib/Parse/ParsePragma.cpp
index 20b87d92b78..106c02b362f 100644
--- a/clang/lib/Parse/ParsePragma.cpp
+++ b/clang/lib/Parse/ParsePragma.cpp
@@ -720,40 +720,68 @@ struct PragmaLoopHintInfo {
   Token Option;
   Token Value;
   bool HasValue;
+  PragmaLoopHintInfo() : HasValue(false) {}
 };
 
-LoopHint Parser::HandlePragmaLoopHint() {
+bool Parser::HandlePragmaLoopHint(LoopHint &Hint) {
   assert(Tok.is(tok::annot_pragma_loop_hint));
   PragmaLoopHintInfo *Info =
       static_cast<PragmaLoopHintInfo *>(Tok.getAnnotationValue());
+  ConsumeToken(); // The annotation token.
 
-  LoopHint Hint;
-  Hint.PragmaNameLoc =
-      IdentifierLoc::create(Actions.Context, Info->PragmaName.getLocation(),
-                            Info->PragmaName.getIdentifierInfo());
-  Hint.OptionLoc =
-      IdentifierLoc::create(Actions.Context, Info->Option.getLocation(),
-                            Info->Option.getIdentifierInfo());
-  if (Info->HasValue) {
-    Hint.Range =
-        SourceRange(Info->Option.getLocation(), Info->Value.getLocation());
-    Hint.ValueLoc =
-        IdentifierLoc::create(Actions.Context, Info->Value.getLocation(),
-                              Info->Value.getIdentifierInfo());
-
+  IdentifierInfo *PragmaNameInfo = Info->PragmaName.getIdentifierInfo();
+  Hint.PragmaNameLoc = IdentifierLoc::create(
+      Actions.Context, Info->PragmaName.getLocation(), PragmaNameInfo);
+
+  IdentifierInfo *OptionInfo = Info->Option.getIdentifierInfo();
+  Hint.OptionLoc = IdentifierLoc::create(
+      Actions.Context, Info->Option.getLocation(), OptionInfo);
+
+  // Return a valid hint if pragma unroll or nounroll were specified
+  // without an argument.
+  bool PragmaUnroll = PragmaNameInfo->getName() == "unroll";
+  bool PragmaNoUnroll = PragmaNameInfo->getName() == "nounroll";
+  if (!Info->HasValue && (PragmaUnroll || PragmaNoUnroll)) {
+    Hint.Range = Info->PragmaName.getLocation();
+    return true;
+  }
+
+  // If no option is specified the argument is assumed to be numeric.
+  bool StateOption = false;
+  if (OptionInfo)
+    StateOption = llvm::StringSwitch<bool>(OptionInfo->getName())
+                      .Case("vectorize", true)
+                      .Case("interleave", true)
+                      .Case("unroll", true)
+                      .Default(false);
+
+  // Validate the argument.
+  if (StateOption) {
+    bool OptionUnroll = OptionInfo->isStr("unroll");
+    SourceLocation StateLoc = Info->Value.getLocation();
+    IdentifierInfo *StateInfo = Info->Value.getIdentifierInfo();
+    if (!StateInfo || ((OptionUnroll ? !StateInfo->isStr("full")
+                                     : !StateInfo->isStr("enable")) &&
+                       !StateInfo->isStr("disable"))) {
+      Diag(StateLoc, diag::err_pragma_invalid_keyword)
+          << /*MissingArgument=*/false << /*FullKeyword=*/OptionUnroll;
+      return false;
+    }
+    Hint.StateLoc = IdentifierLoc::create(Actions.Context, StateLoc, StateInfo);
+  } else {
     // FIXME: We should allow non-type template parameters for the loop hint
     // value. See bug report #19610
     if (Info->Value.is(tok::numeric_constant))
       Hint.ValueExpr = Actions.ActOnNumericConstant(Info->Value).get();
-    else
-      Hint.ValueExpr = nullptr;
-  } else {
-    Hint.Range = SourceRange(Info->PragmaName.getLocation());
-    Hint.ValueLoc = nullptr;
-    Hint.ValueExpr = nullptr;
+    else {
+      Diag(Info->Value.getLocation(), diag::err_pragma_loop_numeric_value);
+      return false;
+    }
   }
 
-  return Hint;
+  Hint.Range =
+      SourceRange(Info->PragmaName.getLocation(), Info->Value.getLocation());
+  return true;
 }
 
 // #pragma GCC visibility comes in two variants:
@@ -1755,12 +1783,10 @@ void PragmaOptimizeHandler::HandlePragma(Preprocessor &PP,
 }
 
 /// \brief Parses loop or unroll pragma hint value and fills in Info.
-static bool ParseLoopHintValue(Preprocessor &PP, Token Tok, Token &PragmaName,
-                               Token &Option, bool &ValueInParens,
+static bool ParseLoopHintValue(Preprocessor &PP, Token &Tok, Token PragmaName,
+                               Token Option, bool ValueInParens,
                                PragmaLoopHintInfo &Info) {
-  ValueInParens = Tok.is(tok::l_paren);
   if (ValueInParens) {
-    PP.Lex(Tok);
     if (Tok.is(tok::r_paren)) {
       // Nothing between the parentheses.
       std::string PragmaString;
@@ -1784,13 +1810,15 @@ static bool ParseLoopHintValue(Preprocessor &PP, Token Tok, Token &PragmaName,
 
   // FIXME: Value should be stored and parsed as a constant expression.
   Token Value = Tok;
+  PP.Lex(Tok);
 
   if (ValueInParens) {
-    PP.Lex(Tok);
+    // Read ')'
     if (Tok.isNot(tok::r_paren)) {
       PP.Diag(Tok.getLocation(), diag::err_expected) << tok::r_paren;
       return true;
     }
+    PP.Lex(Tok);
   }
 
   Info.PragmaName = PragmaName;
@@ -1872,17 +1900,19 @@ void PragmaLoopHintHandler::HandlePragma(Preprocessor &PP,
           << /*MissingOption=*/false << OptionInfo;
       return;
     }
-
-    auto *Info = new (PP.getPreprocessorAllocator()) PragmaLoopHintInfo;
     PP.Lex(Tok);
-    bool ValueInParens;
-    if (ParseLoopHintValue(PP, Tok, PragmaName, Option, ValueInParens, *Info))
-      return;
 
-    if (!ValueInParens) {
-      PP.Diag(Info->Value.getLocation(), diag::err_expected) << tok::l_paren;
+    // Read '('
+    if (Tok.isNot(tok::l_paren)) {
+      PP.Diag(Tok.getLocation(), diag::err_expected) << tok::l_paren;
       return;
     }
+    PP.Lex(Tok);
+
+    auto *Info = new (PP.getPreprocessorAllocator()) PragmaLoopHintInfo;
+    if (ParseLoopHintValue(PP, Tok, PragmaName, Option, /*ValueInParens=*/true,
+                           *Info))
+      return;
 
     // Generate the loop hint token.
     Token LoopHintTok;
@@ -1891,9 +1921,6 @@ void PragmaLoopHintHandler::HandlePragma(Preprocessor &PP,
     LoopHintTok.setLocation(PragmaName.getLocation());
     LoopHintTok.setAnnotationValue(static_cast<void *>(Info));
     TokenList.push_back(LoopHintTok);
-
-    // Get next optimization option.
-    PP.Lex(Tok);
   }
 
   if (Tok.isNot(tok::eod)) {
@@ -1938,7 +1965,6 @@ void PragmaUnrollHintHandler::HandlePragma(Preprocessor &PP,
   if (Tok.is(tok::eod)) {
     // nounroll or unroll pragma without an argument.
     Info->PragmaName = PragmaName;
-    Info->Option = PragmaName;
     Info->HasValue = false;
   } else if (PragmaName.getIdentifierInfo()->getName() == "nounroll") {
     PP.Diag(Tok.getLocation(), diag::warn_pragma_extra_tokens_at_eol)
@@ -1947,9 +1973,12 @@ void PragmaUnrollHintHandler::HandlePragma(Preprocessor &PP,
   } else {
     // Unroll pragma with an argument: "#pragma unroll N" or
     // "#pragma unroll(N)".
-    bool ValueInParens;
-    if (ParseLoopHintValue(PP, Tok, PragmaName, PragmaName, ValueInParens,
-                           *Info))
+    // Read '(' if it exists.
+    bool ValueInParens = Tok.is(tok::l_paren);
+    if (ValueInParens)
+      PP.Lex(Tok);
+
+    if (ParseLoopHintValue(PP, Tok, PragmaName, Token(), ValueInParens, *Info))
       return;
 
     // In CUDA, the argument to '#pragma unroll' should not be contained in
@@ -1958,7 +1987,6 @@ void PragmaUnrollHintHandler::HandlePragma(Preprocessor &PP,
       PP.Diag(Info->Value.getLocation(),
               diag::warn_pragma_unroll_cuda_value_in_parens);
 
-    PP.Lex(Tok);
     if (Tok.isNot(tok::eod)) {
       PP.Diag(Tok.getLocation(), diag::warn_pragma_extra_tokens_at_eol)
           << "unroll";
diff --git a/clang/lib/Parse/ParseStmt.cpp b/clang/lib/Parse/ParseStmt.cpp
index 38723b1293d..a431270d2b1 100644
--- a/clang/lib/Parse/ParseStmt.cpp
+++ b/clang/lib/Parse/ParseStmt.cpp
@@ -1817,10 +1817,11 @@ StmtResult Parser::ParsePragmaLoopHint(StmtVector &Stmts, bool OnlyStatement,
 
   // Get loop hints and consume annotated token.
   while (Tok.is(tok::annot_pragma_loop_hint)) {
-    LoopHint Hint = HandlePragmaLoopHint();
-    ConsumeToken();
+    LoopHint Hint;
+    if (!HandlePragmaLoopHint(Hint))
+      continue;
 
-    ArgsUnion ArgHints[] = {Hint.PragmaNameLoc, Hint.OptionLoc, Hint.ValueLoc,
+    ArgsUnion ArgHints[] = {Hint.PragmaNameLoc, Hint.OptionLoc, Hint.StateLoc,
                             ArgsUnion(Hint.ValueExpr)};
     TempAttrs.addNew(Hint.PragmaNameLoc->Ident, Hint.Range, nullptr,
                      Hint.PragmaNameLoc->Loc, ArgHints, 4,
diff --git a/clang/lib/Sema/SemaStmtAttr.cpp b/clang/lib/Sema/SemaStmtAttr.cpp
index 595aa3656eb..4cb0fde11d0 100644
--- a/clang/lib/Sema/SemaStmtAttr.cpp
+++ b/clang/lib/Sema/SemaStmtAttr.cpp
@@ -47,13 +47,11 @@ static Attr *handleLoopHintAttr(Sema &S, Stmt *St, const AttributeList &A,
                                 SourceRange) {
   IdentifierLoc *PragmaNameLoc = A.getArgAsIdent(0);
   IdentifierLoc *OptionLoc = A.getArgAsIdent(1);
-  IdentifierInfo *OptionInfo = OptionLoc->Ident;
-  IdentifierLoc *ValueLoc = A.getArgAsIdent(2);
-  IdentifierInfo *ValueInfo = ValueLoc ? ValueLoc->Ident : nullptr;
+  IdentifierLoc *StateLoc = A.getArgAsIdent(2);
   Expr *ValueExpr = A.getArgAsExpr(3);
 
-  assert(OptionInfo && "Attribute must have valid option info.");
-
+  bool PragmaUnroll = PragmaNameLoc->Ident->getName() == "unroll";
+  bool PragmaNoUnroll = PragmaNameLoc->Ident->getName() == "nounroll";
   if (St->getStmtClass() != Stmt::DoStmtClass &&
       St->getStmtClass() != Stmt::ForStmtClass &&
       St->getStmtClass() != Stmt::CXXForRangeStmtClass &&
@@ -69,13 +67,16 @@ static Attr *handleLoopHintAttr(Sema &S, Stmt *St, const AttributeList &A,
 
   LoopHintAttr::OptionType Option;
   LoopHintAttr::Spelling Spelling;
-  if (PragmaNameLoc->Ident->getName() == "unroll") {
-    Option = ValueLoc ? LoopHintAttr::UnrollCount : LoopHintAttr::Unroll;
+  if (PragmaUnroll) {
+    Option = ValueExpr ? LoopHintAttr::UnrollCount : LoopHintAttr::Unroll;
     Spelling = LoopHintAttr::Pragma_unroll;
-  } else if (PragmaNameLoc->Ident->getName() == "nounroll") {
+  } else if (PragmaNoUnroll) {
     Option = LoopHintAttr::Unroll;
     Spelling = LoopHintAttr::Pragma_nounroll;
   } else {
+    assert(OptionLoc && OptionLoc->Ident &&
+           "Attribute must have valid option info.");
+    IdentifierInfo *OptionInfo = OptionLoc->Ident;
     Option = llvm::StringSwitch<LoopHintAttr::OptionType>(OptionInfo->getName())
                  .Case("vectorize", LoopHintAttr::Vectorize)
                  .Case("vectorize_width", LoopHintAttr::VectorizeWidth)
@@ -87,35 +88,10 @@ static Attr *handleLoopHintAttr(Sema &S, Stmt *St, const AttributeList &A,
     Spelling = LoopHintAttr::Pragma_clang_loop;
   }
 
-  int ValueInt = -1;
-  if (Option == LoopHintAttr::Unroll &&
-      Spelling == LoopHintAttr::Pragma_unroll) {
-    if (ValueInfo)
-      ValueInt = (ValueInfo->isStr("disable") ? 0 : 1);
-  } else if (Option == LoopHintAttr::Unroll &&
-             Spelling == LoopHintAttr::Pragma_nounroll) {
-    ValueInt = 0;
-  } else if (Option == LoopHintAttr::Vectorize ||
-             Option == LoopHintAttr::Interleave ||
-             Option == LoopHintAttr::Unroll) {
-    // Unrolling uses the keyword "full" rather than "enable" to indicate full
-    // unrolling.
-    const char *TrueKeyword =
-        Option == LoopHintAttr::Unroll ? "full" : "enable";
-    if (!ValueInfo) {
-      S.Diag(ValueLoc->Loc, diag::err_pragma_loop_invalid_keyword)
-          << TrueKeyword;
-      return nullptr;
-    }
-    if (ValueInfo->isStr("disable"))
-      ValueInt = 0;
-    else if (ValueInfo->getName() == TrueKeyword)
-      ValueInt = 1;
-    else {
-      S.Diag(ValueLoc->Loc, diag::err_pragma_loop_invalid_keyword)
-          << TrueKeyword;
-      return nullptr;
-    }
+  int ValueInt = 1;
+  LoopHintAttr::LoopHintState State = LoopHintAttr::Default;
+  if (PragmaNoUnroll) {
+    State = LoopHintAttr::Disable;
   } else if (Option == LoopHintAttr::VectorizeWidth ||
              Option == LoopHintAttr::InterleaveCount ||
              Option == LoopHintAttr::UnrollCount) {
@@ -124,28 +100,39 @@ static Attr *handleLoopHintAttr(Sema &S, Stmt *St, const AttributeList &A,
     llvm::APSInt ValueAPS;
     if (!ValueExpr || !ValueExpr->isIntegerConstantExpr(ValueAPS, S.Context) ||
         (ValueInt = ValueAPS.getSExtValue()) < 1) {
-      S.Diag(ValueLoc->Loc, diag::err_pragma_loop_invalid_value);
+      S.Diag(A.getLoc(), diag::err_pragma_loop_invalid_value);
       return nullptr;
     }
-  } else
-    llvm_unreachable("Unknown loop hint option");
+  } else if (Option == LoopHintAttr::Vectorize ||
+             Option == LoopHintAttr::Interleave ||
+             Option == LoopHintAttr::Unroll) {
+    // Default state is assumed if StateLoc is not specified, such as with
+    // '#pragma unroll'.
+    if (StateLoc && StateLoc->Ident) {
+      if (StateLoc->Ident->isStr("disable"))
+        State = LoopHintAttr::Disable;
+      else
+        State = LoopHintAttr::Enable;
+    }
+  }
 
-  return LoopHintAttr::CreateImplicit(S.Context, Spelling, Option, ValueInt,
-                                      A.getRange());
+  return LoopHintAttr::CreateImplicit(S.Context, Spelling, Option, State,
+                                      ValueInt, A.getRange());
 }
 
-static void CheckForIncompatibleAttributes(
-    Sema &S, const SmallVectorImpl<const Attr *> &Attrs) {
-  // There are 3 categories of loop hints attributes: vectorize, interleave, and
-  // unroll. Each comes in two variants: a boolean form and a numeric form.  The
-  // boolean hints selectively enables/disables the transformation for the loop
-  // (for unroll, a nonzero value indicates full unrolling rather than enabling
-  // the transformation).  The numeric hint provides an integer hint (for
-  // example, unroll count) to the transformer. The following array accumulates
-  // the hints encountered while iterating through the attributes to check for
-  // compatibility.
+static void
+CheckForIncompatibleAttributes(Sema &S,
+                               const SmallVectorImpl<const Attr *> &Attrs) {
+  // There are 3 categories of loop hints attributes: vectorize, interleave,
+  // and unroll. Each comes in two variants: a state form and a numeric form.
+  // The state form selectively defaults/enables/disables the transformation
+  // for the loop (for unroll, default indicates full unrolling rather than
+  // enabling the transformation).  The numeric form form provides an integer
+  // hint (for example, unroll count) to the transformer. The following array
+  // accumulates the hints encountered while iterating through the attributes
+  // to check for compatibility.
   struct {
-    const LoopHintAttr *EnableAttr;
+    const LoopHintAttr *StateAttr;
     const LoopHintAttr *NumericAttr;
   } HintAttrs[] = {{nullptr, nullptr}, {nullptr, nullptr}, {nullptr, nullptr}};
 
@@ -179,8 +166,8 @@ static void CheckForIncompatibleAttributes(
     if (Option == LoopHintAttr::Vectorize ||
         Option == LoopHintAttr::Interleave || Option == LoopHintAttr::Unroll) {
       // Enable|disable hint.  For example, vectorize(enable).
-      PrevAttr = CategoryState.EnableAttr;
-      CategoryState.EnableAttr = LH;
+      PrevAttr = CategoryState.StateAttr;
+      CategoryState.StateAttr = LH;
     } else {
       // Numeric hint.  For example, vectorize_width(8).
       PrevAttr = CategoryState.NumericAttr;
@@ -195,14 +182,15 @@ static void CheckForIncompatibleAttributes(
           << /*Duplicate=*/true << PrevAttr->getDiagnosticName(Policy)
           << LH->getDiagnosticName(Policy);
 
-    if (CategoryState.EnableAttr && CategoryState.NumericAttr &&
-        (Category == Unroll || !CategoryState.EnableAttr->getValue())) {
+    if (CategoryState.StateAttr && CategoryState.NumericAttr &&
+        (Category == Unroll ||
+         CategoryState.StateAttr->getState() == LoopHintAttr::Disable)) {
       // Disable hints are not compatible with numeric hints of the same
       // category.  As a special case, numeric unroll hints are also not
       // compatible with "enable" form of the unroll pragma, unroll(full).
       S.Diag(OptionLoc, diag::err_pragma_loop_compatibility)
           << /*Duplicate=*/false
-          << CategoryState.EnableAttr->getDiagnosticName(Policy)
+          << CategoryState.StateAttr->getDiagnosticName(Policy)
           << CategoryState.NumericAttr->getDiagnosticName(Policy);
     }
   }