Disallow volatile keyword (#8397)

`volatile` is not a valid keyword in HLSL, it is meaningless in this
language.
However, it comes as a result of the fact that HLSL is build on a C/C++
compiler, so there are some C++ artifacts that are part of the language.
This scenario goes into more detail:
llvm/wg-hlsl#300
Though DXC currently does and seems to always have compiled with the
volatile keyword, this is not sensible and should be disallowed.
Fixes #8391
Assisted by: Github Copilot

---------

Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>

Author: bob80905

tools/clang/include/clang/Lex/Token.h

@@ -294,25 +294,18 @@ class Token {
 
   // HLSL Change Starts
   bool isHLSLReserved() const {
-    return
-      is(tok::kw___is_signed) ||
-      is(tok::kw___declspec) ||
-      is(tok::kw___forceinline) ||
-      is(tok::kw_auto) ||
-      is(tok::kw_catch) || is(tok::kw_const_cast) ||
-      is(tok::kw_delete) || is(tok::kw_dynamic_cast) ||
-      is(tok::kw_enum) || is(tok::kw_explicit) ||
-      is(tok::kw_friend) ||
-      is(tok::kw_goto) ||
-      is(tok::kw_mutable) ||
-      is(tok::kw_new) ||
-      is(tok::kw_operator) ||
-      is(tok::kw_protected) || is(tok::kw_private) || is(tok::kw_public) ||
-      is(tok::kw_reinterpret_cast) ||
-      is(tok::kw_signed) || is(tok::kw_sizeof) || is(tok::kw_static_cast) ||
-      is(tok::kw_template) || is(tok::kw_throw) || is(tok::kw_try) || is(tok::kw_typename) ||
-      is(tok::kw_union) || is(tok::kw_using) ||
-      is(tok::kw_virtual);
+    return is(tok::kw___is_signed) || is(tok::kw___declspec) ||
+           is(tok::kw___forceinline) || is(tok::kw_auto) || is(tok::kw_catch) ||
+           is(tok::kw_const_cast) || is(tok::kw_delete) ||
+           is(tok::kw_dynamic_cast) || is(tok::kw_enum) ||
+           is(tok::kw_explicit) || is(tok::kw_friend) || is(tok::kw_goto) ||
+           is(tok::kw_mutable) || is(tok::kw_new) || is(tok::kw_operator) ||
+           is(tok::kw_protected) || is(tok::kw_private) || is(tok::kw_public) ||
+           is(tok::kw_reinterpret_cast) || is(tok::kw_signed) ||
+           is(tok::kw_sizeof) || is(tok::kw_static_cast) ||
+           is(tok::kw_template) || is(tok::kw_throw) || is(tok::kw_try) ||
+           is(tok::kw_typename) || is(tok::kw_union) || is(tok::kw_using) ||
+           is(tok::kw_virtual) || is(tok::kw_volatile);
   }
   // HLSL Change Starts  
 

tools/clang/lib/Parse/ParseDecl.cpp

@@ -4193,6 +4193,10 @@ void Parser::ParseDeclarationSpecifiers(DeclSpec &DS,
                                  getLangOpts());
       break;
     case tok::kw_volatile:
+      // HLSL Change - volatile is reserved for HLSL
+      if (getLangOpts().HLSL)
+        goto HLSLReservedKeyword;
+      // HLSL Change Ends
       isInvalid = DS.SetTypeQual(DeclSpec::TQ_volatile, Loc, PrevSpec, DiagID,
                                  getLangOpts());
       break;

tools/clang/test/HLSL/cpp-errors-hv2015.hlsl

@@ -60,7 +60,7 @@ struct s_with_friend {
 };
 
 typedef int (*fn_int_const)(int) const; // expected-error {{expected ';' after top level declarator}} expected-error {{pointers are unsupported in HLSL}} expected-warning {{declaration does not declare anything}}
-typedef int (*fn_int_volatile)(int) volatile; // expected-error {{expected ';' after top level declarator}} expected-error {{pointers are unsupported in HLSL}} expected-warning {{declaration does not declare anything}}
+typedef int (*fn_int_volatile)(int) volatile; // expected-error {{'volatile' is a reserved keyword in HLSL}} expected-error {{expected ';' after top level declarator}} expected-error {{pointers are unsupported in HLSL}} expected-warning {{declaration does not declare anything}}
 
 void fn_throw() throw() { } // expected-error {{exception specification is unsupported in HLSL}}
 

tools/clang/test/HLSL/cpp-errors.hlsl

@@ -33,6 +33,7 @@ _Bool g_Bool; // expected-error {{unknown type name '_Bool'}}
 _vector int altivec_vector; // expected-error {{expected unqualified-id}} expected-error {{unknown type name '_vector'}}
 
 restrict int g_restrict; // expected-error {{expected unqualified-id}} expected-error {{unknown type name 'restrict'}}
+volatile int g_volatile; // expected-error {{'volatile' is a reserved keyword in HLSL}}
 
 __underlying_type(int) g_underlying_type; // expected-error {{__underlying_type is unsupported in HLSL}}
 _Atomic(something) g_Atomic; // expected-error {{'_Atomic' is a reserved keyword in HLSL}} expected-error {{HLSL requires a type specifier for all declarations}}
@@ -56,7 +57,7 @@ struct s_with_friend {
 };
 
 typedef int (*fn_int_const)(int) const; // expected-error {{expected ';' after top level declarator}} expected-error {{pointers are unsupported in HLSL}} expected-warning {{declaration does not declare anything}}
-typedef int (*fn_int_volatile)(int) volatile; // expected-error {{expected ';' after top level declarator}} expected-error {{pointers are unsupported in HLSL}} expected-warning {{declaration does not declare anything}}
+typedef int (*fn_int_volatile)(int) volatile; // expected-error {{'volatile' is a reserved keyword in HLSL}} expected-error {{expected ';' after top level declarator}} expected-error {{pointers are unsupported in HLSL}} expected-warning {{declaration does not declare anything}}
 
 void fn_throw() throw() { } // expected-error {{exception specification is unsupported in HLSL}}
 

tools/clang/test/HLSL/rewriter/correct_rewrites/varmods-syntax_gold.hlsl

@@ -37,11 +37,7 @@ precise uniform const float g_pre_uni_init = 1.F;
 static float g_sta_init = 1.F;
 static const float g_sta_con_init = 1.F;
 uniform const float g_uni_init = 1.F;
-typedef volatile float2 t_pre_vol;
-typedef const volatile float2 t_pre_vol_con;
 typedef const float2 t_pre_con;
-typedef volatile float2 t_vol;
-typedef const volatile float2 t_vol_con;
 typedef const float2 t_con;
 struct s_storage_mods {
   precise float2 f_pre;
@@ -222,22 +218,12 @@ float4 foo_interpolation_different_decl(sample float4 val) {
 void vain() {
   precise float l_pre;
   static precise float l_pre_sta;
-  static precise volatile float l_pre_sta_vol;
-  static precise const volatile float l_pre_sta_vol_con;
   static precise const float l_pre_sta_con;
-  precise volatile float l_pre_vol;
   static float l_sta;
-  static volatile float l_sta_vol;
-  static const volatile float l_sta_vol_con;
   static const float l_sta_con;
-  volatile float l_vol;
-  static precise const volatile float l_pre_sta_vol_con_init = 0.;
   static precise const float l_pre_sta_con_init = 0.;
-  precise const volatile float l_pre_vol_con_init = 0.;
   precise const float l_pre_con_init = 0.;
-  static const volatile float l_sta_vol_con_init = 0.;
   static const float l_sta_con_init = 0.;
-  const volatile float l_vol_con_init = 0.;
   const float l_con_init = 0.;
 }
 

tools/clang/test/HLSL/rewriter/varmods-syntax_noerr.hlsl

@@ -288,8 +288,8 @@ uniform float g_uni_init = 1.0f;
 //typedef precise uniform volatile float2 t_pre_uni_vol;      /* expected-error {{'uniform' is not a valid modifier for a typedef}} fxc-error {{X3000: syntax error: unexpected token 'uniform'}} */
 //typedef precise uniform volatile const float2 t_pre_uni_vol_con;    /* expected-error {{'uniform' is not a valid modifier for a typedef}} fxc-error {{X3000: syntax error: unexpected token 'uniform'}} */
 //typedef precise uniform const float2 t_pre_uni_con;         /* expected-error {{'uniform' is not a valid modifier for a typedef}} fxc-error {{X3000: syntax error: unexpected token 'uniform'}} */
-typedef precise volatile float2 t_pre_vol;
-typedef precise volatile const float2 t_pre_vol_con;
+//typedef precise volatile float2 t_pre_vol;    /* expected-error {{'volatile' is a reserved keyword in HLSL}} */
+//typedef precise volatile const float2 t_pre_vol_con;    /* expected-error {{'volatile' is a reserved keyword in HLSL}} */
 typedef precise const float2 t_pre_con;
 //typedef static float2 t_sta;                                /* expected-error {{cannot combine with previous 'typedef' declaration specifier}} fxc-error {{X3000: syntax error: unexpected token 'static'}} */
 //typedef static volatile float2 t_sta_vol;                   /* expected-error {{cannot combine with previous 'typedef' declaration specifier}} fxc-error {{X3000: syntax error: unexpected token 'static'}} */
@@ -299,8 +299,8 @@ typedef precise const float2 t_pre_con;
 //typedef uniform volatile float2 t_uni_vol;                  /* expected-error {{'uniform' is not a valid modifier for a typedef}} fxc-error {{X3000: syntax error: unexpected token 'uniform'}} */
 //typedef uniform volatile const float2 t_uni_vol_con;        /* expected-error {{'uniform' is not a valid modifier for a typedef}} fxc-error {{X3000: syntax error: unexpected token 'uniform'}} */
 //typedef uniform const float2 t_uni_con;                     /* expected-error {{'uniform' is not a valid modifier for a typedef}} fxc-error {{X3000: syntax error: unexpected token 'uniform'}} */
-typedef volatile float2 t_vol;
-typedef volatile const float2 t_vol_con;
+//typedef volatile float2 t_vol;    /* expected-error {{'volatile' is a reserved keyword in HLSL}} */
+//typedef volatile const float2 t_vol_con;    /* expected-error {{'volatile' is a reserved keyword in HLSL}} */
 typedef const float2 t_con;
 // GENERATED_CODE:END
 
@@ -668,26 +668,26 @@ void vain() {
     //extern const float l_ext_con;                           /* expected-error {{'extern' is not a valid modifier for a local variable}} fxc-error {{X3006: 'l_ext_con': local variables cannot be declared 'extern'}} fxc-error {{X3012: 'l_ext_con': missing initial value}} */
     precise float l_pre;
     precise static float l_pre_sta;
-    precise static volatile float l_pre_sta_vol;
-    precise static volatile const float l_pre_sta_vol_con;
+    //precise static volatile float l_pre_sta_vol;    /* expected-error {{'volatile' is a reserved keyword in HLSL}} */
+    //precise static volatile const float l_pre_sta_vol_con;    /* expected-error {{'volatile' is a reserved keyword in HLSL}} */
     precise static const float l_pre_sta_con;
     //precise uniform float l_pre_uni;                        /* expected-error {{'uniform' is not a valid modifier for a local variable}} fxc-error {{X3047: 'l_pre_uni': local variables cannot be declared 'uniform'}} */
     //precise uniform volatile float l_pre_uni_vol;           /* expected-error {{'uniform' is not a valid modifier for a local variable}} fxc-error {{X3047: 'l_pre_uni_vol': local variables cannot be declared 'uniform'}} */
     //precise uniform volatile const float l_pre_uni_vol_con; /* expected-error {{'uniform' is not a valid modifier for a local variable}} fxc-error {{X3012: 'l_pre_uni_vol_con': missing initial value}} fxc-error {{X3047: 'l_pre_uni_vol_con': local variables cannot be declared 'uniform'}} */
     //precise uniform const float l_pre_uni_con;              /* expected-error {{'uniform' is not a valid modifier for a local variable}} fxc-error {{X3012: 'l_pre_uni_con': missing initial value}} fxc-error {{X3047: 'l_pre_uni_con': local variables cannot be declared 'uniform'}} */
-    precise volatile float l_pre_vol;
-    //precise volatile const float l_pre_vol_con;             /* fxc-error {{X3012: 'l_pre_vol_con': missing initial value}} */
+    //precise volatile float l_pre_vol;    /* expected-error {{'volatile' is a reserved keyword in HLSL}} */
+    //precise volatile const float l_pre_vol_con;             /* fxc-error {{X3012: 'l_pre_vol_con': missing initial value}} expected-error {{'volatile' is a reserved keyword in HLSL}} */
     //precise const float l_pre_con;                          /* fxc-error {{X3012: 'l_pre_con': missing initial value}} */
     static float l_sta;
-    static volatile float l_sta_vol;
-    static volatile const float l_sta_vol_con;
+    //static volatile float l_sta_vol;    /* expected-error {{'volatile' is a reserved keyword in HLSL}} */
+    //static volatile const float l_sta_vol_con;    /* expected-error {{'volatile' is a reserved keyword in HLSL}} */
     static const float l_sta_con;
     //uniform float l_uni;                                    /* expected-error {{'uniform' is not a valid modifier for a local variable}} fxc-error {{X3047: 'l_uni': local variables cannot be declared 'uniform'}} */
     //uniform volatile float l_uni_vol;                       /* expected-error {{'uniform' is not a valid modifier for a local variable}} fxc-error {{X3047: 'l_uni_vol': local variables cannot be declared 'uniform'}} */
     //uniform volatile const float l_uni_vol_con;             /* expected-error {{'uniform' is not a valid modifier for a local variable}} fxc-error {{X3012: 'l_uni_vol_con': missing initial value}} fxc-error {{X3047: 'l_uni_vol_con': local variables cannot be declared 'uniform'}} */
     //uniform const float l_uni_con;                          /* expected-error {{'uniform' is not a valid modifier for a local variable}} fxc-error {{X3012: 'l_uni_con': missing initial value}} fxc-error {{X3047: 'l_uni_con': local variables cannot be declared 'uniform'}} */
-    volatile float l_vol;
-    //volatile const float l_vol_con;                         /* fxc-error {{X3012: 'l_vol_con': missing initial value}} */
+    //volatile float l_vol;    /* expected-error {{'volatile' is a reserved keyword in HLSL}} */
+    //volatile const float l_vol_con;                         /* fxc-error {{X3012: 'l_vol_con': missing initial value}} expected-error {{'volatile' is a reserved keyword in HLSL}} */
     //const float l_con;                                      /* fxc-error {{X3012: 'l_con': missing initial value}} */
     // GENERATED_CODE:END
     // Now with const vars initialized:
@@ -713,17 +713,17 @@ void vain() {
     //extern uniform const float l_ext_uni_con_init = 0.0;    /* expected-error {{'extern' is not a valid modifier for a local variable}} expected-error {{'uniform' is not a valid modifier for a local variable}} fxc-error {{X3006: 'l_ext_uni_con_init': local variables cannot be declared 'extern'}} fxc-error {{X3012: 'l_ext_uni_con_init': missing initial value}} fxc-error {{X3047: 'l_ext_uni_con_init': local variables cannot be declared 'uniform'}} */
     //extern volatile const float l_ext_vol_con_init = 0.0;   /* expected-error {{'extern' is not a valid modifier for a local variable}} fxc-error {{X3006: 'l_ext_vol_con_init': local variables cannot be declared 'extern'}} fxc-error {{X3012: 'l_ext_vol_con_init': missing initial value}} */
     //extern const float l_ext_con_init = 0.0;                /* expected-error {{'extern' is not a valid modifier for a local variable}} fxc-error {{X3006: 'l_ext_con_init': local variables cannot be declared 'extern'}} fxc-error {{X3012: 'l_ext_con_init': missing initial value}} */
-    precise static volatile const float l_pre_sta_vol_con_init = 0.0;
+    //precise static volatile const float l_pre_sta_vol_con_init = 0.0;    /* expected-error {{'volatile' is a reserved keyword in HLSL}} */
     precise static const float l_pre_sta_con_init = 0.0;
     //precise uniform volatile const float l_pre_uni_vol_con_init = 0.0;    /* expected-error {{'uniform' is not a valid modifier for a local variable}} fxc-error {{X3012: 'l_pre_uni_vol_con_init': missing initial value}} fxc-error {{X3047: 'l_pre_uni_vol_con_init': local variables cannot be declared 'uniform'}} */
     //precise uniform const float l_pre_uni_con_init = 0.0;   /* expected-error {{'uniform' is not a valid modifier for a local variable}} fxc-error {{X3012: 'l_pre_uni_con_init': missing initial value}} fxc-error {{X3047: 'l_pre_uni_con_init': local variables cannot be declared 'uniform'}} */
-    precise volatile const float l_pre_vol_con_init = 0.0;
+    //precise volatile const float l_pre_vol_con_init = 0.0;    /* expected-error {{'volatile' is a reserved keyword in HLSL}} */
     precise const float l_pre_con_init = 0.0;
-    static volatile const float l_sta_vol_con_init = 0.0;
+    //static volatile const float l_sta_vol_con_init = 0.0;    /* expected-error {{'volatile' is a reserved keyword in HLSL}} */
     static const float l_sta_con_init = 0.0;
     //uniform volatile const float l_uni_vol_con_init = 0.0;  /* expected-error {{'uniform' is not a valid modifier for a local variable}} fxc-error {{X3012: 'l_uni_vol_con_init': missing initial value}} fxc-error {{X3047: 'l_uni_vol_con_init': local variables cannot be declared 'uniform'}} */
     //uniform const float l_uni_con_init = 0.0;               /* expected-error {{'uniform' is not a valid modifier for a local variable}} fxc-error {{X3012: 'l_uni_con_init': missing initial value}} fxc-error {{X3047: 'l_uni_con_init': local variables cannot be declared 'uniform'}} */
-    volatile const float l_vol_con_init = 0.0;
+    //volatile const float l_vol_con_init = 0.0;    /* expected-error {{'volatile' is a reserved keyword in HLSL}} */
     const float l_con_init = 0.0;
     // GENERATED_CODE:END
 
@@ -969,4 +969,4 @@ class C
     //out float fn_out() { return 1.0f; }                     /* expected-error {{HLSL usage 'out' is only valid on a parameter}} fxc-error {{X3000: syntax error: unexpected token 'out'}} */
     //inout float fn_inout() { return 1.0f; }                 /* expected-error {{HLSL usage 'inout' is only valid on a parameter}} fxc-error {{X3000: syntax error: unexpected token 'inout'}} */
 
-};
+};

tools/clang/test/HLSLFileCheck/hlsl/types/conversions/varmods-syntax_Mod.hlsl

@@ -40,7 +40,7 @@ def make_trunc(num):
     return trunc
 linear_mods = ['linear', 'sample', 'noperspective', 'centroid']
 interp_combos = [('nointerpolation',)] + [('nointerpolation', mod) for mod in linear_mods] + list(gen_combos(linear_mods))
-storage_mods = 'groupshared extern precise static uniform volatile const'.split()
+storage_mods = 'groupshared extern precise static uniform const'.split()
 bad_storage_combos = [('groupshared', 'extern'), 
                       ('extern', 'static'),
                       ('static', 'uniform')]
@@ -127,11 +127,7 @@ const float g_con_init = 1.0f;                              /* fxc-warning {{X32
 // <py::lines('GENERATED_CODE')>modify(lines, gen_code('typedef %(mods)s float2 t_%(id)s;', storage_combos))</py>
 // GENERATED_CODE:BEGIN
 typedef precise float2 t_pre;
-typedef precise volatile float2 t_pre_vol;
-typedef precise volatile const float2 t_pre_vol_con;
 typedef precise const float2 t_pre_con;
-typedef volatile float2 t_vol;
-typedef volatile const float2 t_vol_con;
 typedef const float2 t_con;
 // GENERATED_CODE:END
 
@@ -294,26 +290,16 @@ void main() {
     // GENERATED_CODE:BEGIN
     precise float l_pre;
     precise static float l_pre_sta;
-    precise static volatile float l_pre_sta_vol;
-    precise static volatile const float l_pre_sta_vol_con;
     precise static const float l_pre_sta_con;
-    precise volatile float l_pre_vol;
     static float l_sta;
-    static volatile float l_sta_vol;
-    static volatile const float l_sta_vol_con;
     static const float l_sta_con;
-    volatile float l_vol;
     // GENERATED_CODE:END
     // Now with const vars initialized:
     // <py::lines('GENERATED_CODE')>modify(lines, gen_code('%(mods)s float l_%(id)s_init = 0.0;', filter(lambda combo: 'const' in combo, storage_combos)))</py>
     // GENERATED_CODE:BEGIN
-    precise static volatile const float l_pre_sta_vol_con_init = 0.0;
     precise static const float l_pre_sta_con_init = 0.0;
-    precise volatile const float l_pre_vol_con_init = 0.0;
     precise const float l_pre_con_init = 0.0;
-    static volatile const float l_sta_vol_con_init = 0.0;
     static const float l_sta_con_init = 0.0;
-    volatile const float l_vol_con_init = 0.0;
     const float l_con_init = 0.0;
     // GENERATED_CODE:END
 
@@ -378,4 +364,4 @@ class C
     // GENERATED_CODE:END
 
 
-};
+};