Update the way we handle -sycl-std= based on community review feedback

When upstreaming these changes, community asked for some simple
modifications in https://reviews.llvm.org/D97717. This brings those
changes back downstream for parity.

Author: AaronBallman

clang/include/clang/Driver/Options.td

@@ -4295,10 +4295,6 @@ def fsycl : Flag<["-"], "fsycl">, Flags<[NoXarchOption, CoreOption]>, Group<sycl
   HelpText<"Enables SYCL kernels compilation for device">;
 def fno_sycl : Flag<["-"], "fno-sycl">, Flags<[NoXarchOption, CoreOption]>, Group<sycl_Group>,
   HelpText<"Disables SYCL kernels compilation for device">;
-def sycl_std_EQ : Joined<["-"], "sycl-std=">, Group<sycl_Group>, Flags<[CC1Option, NoArgumentUnused, CoreOption]>,
-  HelpText<"SYCL language standard to compile for.">, Values<"2020,2017,121,1.2.1,sycl-1.2.1">,
-  NormalizedValues<["SYCL_2020", "SYCL_2017", "SYCL_2017", "SYCL_2017", "SYCL_2017"]>, NormalizedValuesScope<"LangOptions">,
-  MarshallingInfoString<LangOpts<"SYCLVersion">, "SYCL_None">, AutoNormalizeEnum;
 defm sycl_esimd: BoolFOption<"sycl-explicit-simd",
   LangOpts<"SYCLExplicitSIMD">, DefaultFalse,
   PosFlag<SetTrue, [CC1Option], "Enable">, NegFlag<SetFalse, [], "Disable">,
@@ -5520,6 +5516,15 @@ def fsycl_is_device : Flag<["-"], "fsycl-is-device">,
 def fsycl_is_host : Flag<["-"], "fsycl-is-host">,
   HelpText<"SYCL host compilation">,
   MarshallingInfoFlag<LangOpts<"SYCLIsHost">>;
+def sycl_std_EQ : Joined<["-"], "sycl-std=">, Group<sycl_Group>,
+  Flags<[CC1Option, NoArgumentUnused, CoreOption]>,
+  HelpText<"SYCL language standard to compile for.">,
+  Values<"2020,2017,121,1.2.1,sycl-1.2.1">,
+  NormalizedValues<["SYCL_2020", "SYCL_2017", "SYCL_2017", "SYCL_2017", "SYCL_2017"]>,
+  NormalizedValuesScope<"LangOptions">,
+  MarshallingInfoString<LangOpts<"SYCLVersion">, "SYCL_None">,
+  AutoNormalizeEnum,
+  ShouldParseIf<!strconcat(fsycl_is_device.KeyPath, "||", fsycl_is_host.KeyPath)>;
 def fsycl_int_header : Separate<["-"], "fsycl-int-header">,
   HelpText<"Generate SYCL integration header into this file.">,
   MarshallingInfoString<LangOpts<"SYCLIntHeader">>;

clang/unittests/Frontend/CompilerInvocationTest.cpp

@@ -531,46 +531,40 @@ TEST_F(CommandLineTest, ConditionalParsingIfFalseFlagPresent) {
   ASSERT_FALSE(Diags->hasErrorOccurred());
   ASSERT_FALSE(Invocation.getLangOpts()->SYCLIsDevice);
   ASSERT_FALSE(Invocation.getLangOpts()->SYCLIsHost);
-  ASSERT_EQ(Invocation.getLangOpts()->getSYCLVersion(), LangOptions::SYCL_2017);
+  ASSERT_EQ(Invocation.getLangOpts()->getSYCLVersion(), LangOptions::SYCL_None);
 
   Invocation.generateCC1CommandLine(GeneratedArgs, *this);
 
   ASSERT_THAT(GeneratedArgs, Not(Contains(StrEq("-fsycl-is-device"))));
   ASSERT_THAT(GeneratedArgs, Not(Contains(StrEq("-fsycl-is-host"))));
-
-  // FIXME: generateCC1CommandLine is only used by the unit test system and
-  // cannot handle this case. It passes along the -sycl-std because the option
-  // definition does not specify that it relies on -fsycl any longer (because
-  // there is no syntax I could find that would allow it). However, the option
-  // is handled properly on a real invocation. See: Clang::ConstructJob().
-  ASSERT_THAT(GeneratedArgs, Contains(HasSubstr("-sycl-std=")));
+  ASSERT_THAT(GeneratedArgs, Not(Contains(HasSubstr("-sycl-std="))));
 }
 
 TEST_F(CommandLineTest, ConditionalParsingIfTrueFlagNotPresent) {
-  const char *Args[] = {"-fsycl"};
+  const char *Args[] = {"-fsycl-is-host"};
 
   CompilerInvocation::CreateFromArgs(Invocation, Args, *Diags);
 
-  ASSERT_TRUE(Diags->hasErrorOccurred());
+  ASSERT_FALSE(Diags->hasErrorOccurred());
   ASSERT_EQ(Invocation.getLangOpts()->getSYCLVersion(), LangOptions::SYCL_None);
 
   Invocation.generateCC1CommandLine(GeneratedArgs, *this);
 
-  ASSERT_THAT(GeneratedArgs, Not(Contains(StrEq("-fsycl"))));
+  ASSERT_THAT(GeneratedArgs, Contains(StrEq("-fsycl-is-host")));
   ASSERT_THAT(GeneratedArgs, Not(Contains(HasSubstr("-sycl-std="))));
 }
 
 TEST_F(CommandLineTest, ConditionalParsingIfTrueFlagPresent) {
-  const char *Args[] = {"-fsycl", "-sycl-std=2017"};
+  const char *Args[] = {"-fsycl-is-device", "-sycl-std=2017"};
 
   CompilerInvocation::CreateFromArgs(Invocation, Args, *Diags);
 
-  ASSERT_TRUE(Diags->hasErrorOccurred());
+  ASSERT_FALSE(Diags->hasErrorOccurred());
   ASSERT_EQ(Invocation.getLangOpts()->getSYCLVersion(), LangOptions::SYCL_2017);
 
   Invocation.generateCC1CommandLine(GeneratedArgs, *this);
 
-  ASSERT_THAT(GeneratedArgs, Not(Contains(StrEq("-fsycl"))));
+  ASSERT_THAT(GeneratedArgs, Contains(StrEq("-fsycl-is-device")));
   ASSERT_THAT(GeneratedArgs, Contains(StrEq("-sycl-std=2017")));
 }