Expose the packing function so we can check varyings packing per program

include/GLSLANG/ShaderLang.h

@@ -163,6 +163,11 @@ typedef enum {
   SH_DEPENDENCY_GRAPH = 0x0400,
 
   // Enforce the GLSL 1.017 Appendix A section 7 packing restrictions.
+  // This flag only enforces (and can only enforce) the packing
+  // restrictions for uniform variables in both vertex and fragment
+  // shaders. ShCheckVariablesWithinPackingLimits() lets embedders
+  // enforce the packing restrictions for varying variables during
+  // program link time.
   SH_ENFORCE_PACKING_RESTRICTIONS = 0x0800,
 
   // This flag ensures all indirect (expression-based) array indexing
@@ -434,6 +439,25 @@ COMPILER_EXPORT void ShGetInfoPointer(const ShHandle handle,
                                       ShShaderInfo pname,
                                       void** params);
 
+typedef struct
+{
+    ShDataType type;
+    int size;
+} ShVariableInfo;
+
+// Returns 1 if the passed in variables pack in maxVectors following
+// the packing rules from the GLSL 1.017 spec, Appendix A, section 7.
+// Returns 0 otherwise. Also look at the SH_ENFORCE_PACKING_RESTRICTIONS
+// flag above.
+// Parameters:
+// maxVectors: the available rows of registers.
+// varInfoArray: an array of variable info (types and sizes).
+// varInfoArraySize: the size of the variable array.
+COMPILER_EXPORT int ShCheckVariablesWithinPackingLimits(
+    int maxVectors,
+    ShVariableInfo* varInfoArray,
+    size_t varInfoArraySize);
+
 #ifdef __cplusplus
 }
 #endif

src/common/version.h

 #define MAJOR_VERSION 1
 #define MINOR_VERSION 2
 #define BUILD_VERSION 0
-#define BUILD_REVISION 2442
+#define BUILD_REVISION 2443
 
 #define STRINGIFY(x) #x
 #define MACRO_STRINGIFY(x) STRINGIFY(x)

src/compiler/ShaderLang.cpp

@@ -15,6 +15,7 @@
 #include "compiler/preprocessor/length_limits.h"
 #include "compiler/ShHandle.h"
 #include "compiler/TranslatorHLSL.h"
+#include "compiler/VariablePacker.h"
 
 //
 // This is the platform independent interface between an OGL driver
@@ -368,3 +369,19 @@ void ShGetInfoPointer(const ShHandle handle, ShShaderInfo pname, void** params)
     default: UNREACHABLE();
     }
 }
+
+int ShCheckVariablesWithinPackingLimits(
+    int maxVectors, ShVariableInfo* varInfoArray, size_t varInfoArraySize)
+{
+    if (varInfoArraySize == 0)
+        return 1;
+    ASSERT(varInfoArray);
+    TVariableInfoList variables;
+    for (size_t ii = 0; ii < varInfoArraySize; ++ii)
+    {
+        TVariableInfo var(varInfoArray[ii].type, varInfoArray[ii].size);
+        variables.push_back(var);
+    }
+    VariablePacker packer;
+    return packer.CheckVariablesWithinPackingLimits(maxVectors, variables) ? 1 : 0;
+}