adding root signature parser

Author: joaosaffran-zz

clang/include/clang/Parse/Parser.h

@@ -3052,8 +3052,12 @@ class Parser : public CodeCompletionHandler {
   void ParseHLSLAnnotations(ParsedAttributes &Attrs,
                             SourceLocation *EndLoc = nullptr,
                             bool CouldBeBitField = false);
+
   Decl *ParseHLSLBuffer(SourceLocation &DeclEnd);
 
+  Attr *ParseHLSLRootSignature(StringRef Signature, ParsedAttributes &Attrs,
+                               SourceLocation *EndLoc = nullptr);
+
   void MaybeParseMicrosoftAttributes(ParsedAttributes &Attrs) {
     if ((getLangOpts().MicrosoftExt || getLangOpts().HLSL) &&
         Tok.is(tok::l_square)) {

clang/lib/Parse/CMakeLists.txt

@@ -14,6 +14,7 @@ add_clang_library(clangParse
   ParseExpr.cpp
   ParseExprCXX.cpp
   ParseHLSL.cpp
+  ParseHLSLRootSignature.cpp
   ParseInit.cpp
   ParseObjc.cpp
   ParseOpenMP.cpp

clang/lib/Parse/ParseHLSLRootSignature.cpp

@@ -0,0 +1,124 @@
+#include "clang/AST/Attr.h"
+#include "clang/Parse/Parser.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/ADT/StringSwitch.h"
+#include "llvm/Support/ErrorHandling.h"
+#include <cassert>
+#include <memory>
+
+using namespace clang;
+
+struct RSTknInfo {
+  enum RSTok {
+    RootFlags,
+    RootConstants,
+    RootCBV,
+    RootSRV,
+    RootUAV,
+    DescriptorTable,
+    StaticSampler,
+    Number,
+    Character,
+    StrConst,
+    EoF
+  };
+
+  RSTknInfo() {}
+
+  RSTok Kind = RSTok::EoF;
+  StringRef Text;
+};
+
+class RootSignaturParser {
+  StringRef Signature;
+
+public:
+  RootSignaturParser(StringRef Signature) : Signature(Signature) {}
+
+  void ParseRootDefinition() {
+    do {
+      getNextToken();
+
+      switch (CurTok.Kind) {
+
+      case RSTknInfo::RootFlags:
+        getNextToken();
+        assert(CurTok.Kind == RSTknInfo::Character && CurTok.Text == "(" &&
+               "Missing tkn in root signature");
+
+        ParseRootFlag();
+
+        break;
+      default:
+        llvm_unreachable("Root Element still not suported");
+      }
+    } while (CurTok.Kind != RSTknInfo::EoF);
+  }
+
+private:
+  RSTknInfo CurTok;
+  std::string IdentifierStr;
+
+  void consumeWhitespace() { Signature = Signature.ltrim(" \t\v\f\r"); }
+
+  RSTknInfo gettok() {
+    char LastChar = ' ';
+    RSTknInfo Response;
+
+    while (isspace(LastChar))
+      LastChar = Signature.front();
+
+    if (isalpha(LastChar)) {
+      IdentifierStr = LastChar;
+      while (isalnum((LastChar = Signature.front())))
+        IdentifierStr += LastChar;
+
+      RSTknInfo::RSTok Tok =
+          llvm::StringSwitch<RSTknInfo::RSTok>(IdentifierStr)
+              .Case("RootFlags", RSTknInfo::RootFlags)
+              .Case("RootConstants", RSTknInfo::RootConstants)
+              .Case("RootCBV", RSTknInfo::RootCBV)
+              .Case("RootSRV", RSTknInfo::RootSRV)
+              .Case("RootUAV", RSTknInfo::RootUAV)
+              .Case("DescriptorTable", RSTknInfo::DescriptorTable)
+              .Case("StaticSampler", RSTknInfo::StaticSampler)
+              .Default(RSTknInfo::StrConst);
+
+      Response.Kind = Tok;
+      Response.Text = StringRef(IdentifierStr);
+      return Response;
+    }
+
+    if (isdigit(LastChar)) {
+      std::string NumStr;
+
+      do {
+        NumStr += LastChar;
+        LastChar = Signature.front();
+      } while (isdigit(LastChar));
+
+      Response.Kind = RSTknInfo::Number;
+      Response.Text = StringRef(IdentifierStr);
+      return Response;
+    }
+
+    if (LastChar == EOF) {
+      Response.Kind = RSTknInfo::EoF;
+      return Response;
+    }
+
+    Response.Kind = RSTknInfo::Character;
+    Response.Text = StringRef(std::string(1, LastChar));
+    return Response;
+  }
+
+  RSTknInfo getNextToken() { return CurTok = gettok(); }
+};
+
+Attr *Parser::ParseHLSLRootSignature(StringRef Signature,
+                                     ParsedAttributes &Attrs,
+                                     SourceLocation *EndLoc) {
+  RootSignaturParser RSParser(Signature);
+  RSParser.ParseRootDefinition();
+  return nullptr;
+}