ESSL/SPV: Fix #1856: Allow ESSL shaders to compile to OpenGL SPIR-V.

README.md

@@ -293,7 +293,7 @@ class TProgram
 
 For just validating (not generating code), subsitute these calls:
 
-```
+```cxx
     setEnvInput(EShSourceHlsl or EShSourceGlsl, stage,  EShClientNone, 0);
     setEnvClient(EShClientNone, 0);
     setEnvTarget(EShTargetNone, 0);

Test/baseResults/glspv.esversion.vert.out

 glspv.esversion.vert
-ERROR: #version: ES shaders for OpenGL SPIR-V are not supported
-ERROR: 1 compilation errors.  No code generated.
+// Module Version 10000
+// Generated by (magic number): 80007
+// Id's are bound by 10
 
-
-SPIR-V is not generated for failed compile or link
+                              Capability Shader
+               1:             ExtInstImport  "GLSL.std.450"
+                              MemoryModel Logical GLSL450
+                              EntryPoint Vertex 4  "main" 8 9
+                              Source ESSL 310
+                              Name 4  "main"
+                              Name 8  "gl_VertexID"
+                              Name 9  "gl_InstanceID"
+                              Decorate 8(gl_VertexID) BuiltIn VertexId
+                              Decorate 9(gl_InstanceID) BuiltIn InstanceId
+               2:             TypeVoid
+               3:             TypeFunction 2
+               6:             TypeInt 32 1
+               7:             TypePointer Input 6(int)
+  8(gl_VertexID):      7(ptr) Variable Input
+9(gl_InstanceID):      7(ptr) Variable Input
+         4(main):           2 Function None 3
+               5:             Label
+                              Return
+                              FunctionEnd

glslang/MachineIndependent/ShaderLang.cpp

@@ -646,14 +646,9 @@ bool DeduceVersionProfile(TInfoSink& infoSink, EShLanguage stage, bool versionNo
     if (spvVersion.spv != 0) {
         switch (profile) {
         case EEsProfile:
-            if (spvVersion.vulkan > 0 && version < 310) {
+            if (version < 310) {
                 correct = false;
-                infoSink.info.message(EPrefixError, "#version: ES shaders for Vulkan SPIR-V require version 310 or higher");
-                version = 310;
-            }
-            if (spvVersion.openGl >= 100) {
-                correct = false;
-                infoSink.info.message(EPrefixError, "#version: ES shaders for OpenGL SPIR-V are not supported");
+                infoSink.info.message(EPrefixError, "#version: ES shaders for SPIR-V require version 310 or higher");
                 version = 310;
             }
             break;

glslang/Public/ShaderLang.h

@@ -126,8 +126,8 @@ class TType;
 
 typedef enum {
     EShSourceNone,
-    EShSourceGlsl,
-    EShSourceHlsl,
+    EShSourceGlsl,               // GLSL, includes ESSL (OpenGL ES GLSL)
+    EShSourceHlsl,               // HLSL
 } EShSource;                     // if EShLanguage were EShStage, this could be EShLanguage instead
 
 typedef enum {