GLSlang compiler

GLSlang Front-End GL Shading Language compiler front end developed by 3DLabs. Redistribution and use in source and binary forms, with or without modification, are permitted. Ready to build on Linux and Windows  Windows → Requires Visual Studio.NET  Linux → Compilation problems with libc versión in fargas By now compiled in Visual Studio.NET

GLSlang compiler source code It´s completely machine independent code Code is parsed by flex/bison, with the aid of a symbol table and an intermediate representation The intermediate representation (IR) is very high-level, and represented as an in memory tree  No lose information from the original program  In the IR constants are propogated and folded... ... and some dead code is eliminated.

GLSlang compiler source code The back-end compiler has to traverse the IR-tree and create an internal object code representation. It has to derive from TCompiler : class TGenericCompiler : public TCompiler { public: TGenericCompiler(EShLanguage l, int dOptions) : TCompiler(l, infoSink), debugOptions(dOptions) { } virtual bool compile(TIntermNode* root); TInfoSink infoSink; int debugOptions; };

GLSlang compiler source code intermediate.h has the definition of the IR tree. Nodes in the IR tree are defined as a hierarchy of classes derived from TIntermNode. Example: class TIntermLoop : public TIntermNode; represents a loop in the tree. class TIntermOperator : public TIntermTyped; represents an operator in the tree.

GLSlang generic compiler output A little back end is implemented Only to print a brief description of the IR tree. Example (the glslang code): varying vec3 color; void main() { color = vec3(1.0, 1.0, 1.0); gl_Position = gl_ModelViewProjectionMatrix * gl_Vertex; }

GLSlang generic compiler output #### BEGIN COMPILER 0 INFO LOG #### 0:? Sequence 0:37 Function Definition: main( (void) 0:37 Function Parameters: 0:39 Sequence 0:39 move second child to first child (3-component vector of float) 0:39 'color' (varying 3-component vector of float) 0:39 Construct vec3 (const 3-component vector of float) 0: (const float) 0:41 move second child to first child (4-component vector of float) 0:41 'gl_Position' (Position 4-component vector of float) 0:41 matrix-times-vector (4-component vector of float) 0:41 'gl_ModelViewProjectionMatrix' (uniform 4X4 matrix of float) 0:41 'gl_Vertex' (attribute 4-component vector of float) #### END COMPILER 0 INFO LOG #### #### BEGIN LINKER INFO LOG #### #### END LINKER INFO LOG #### The output: