assembler: Don't change the size of opcodes!

Until now, the assembler had relocation-related fields added to struct
brw_instruction. This changes the size of the structure and break code
assuming the opcode structure is really 16 bytes, for instance the
emission code in brw_eu_emit.c.

With this commit, we build on the infrastructure that slowly emerged in
the few previous commits to add a relocatable instruction with the
needed fields.

Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>

assembler/gen4asm.h

@@ -137,6 +137,7 @@ typedef struct {
 
 enum assembler_instruction_type {
     GEN4ASM_INSTRUCTION_GEN,
+    GEN4ASM_INSTRUCTION_GEN_RELOCATABLE,
     GEN4ASM_INSTRUCTION_LABEL,
 };
 
@@ -144,6 +145,12 @@ struct label_instruction {
     char   *name;
 };
 
+struct relocatable_instruction {
+    struct brw_instruction gen;
+    char *first_reloc_target, *second_reloc_target; // JIP and UIP respectively
+    GLint first_reloc_offset, second_reloc_offset; // in number of instructions
+};
+
 /**
  * This structure is just the list container for instructions accumulated by
  * the parser and labels.
@@ -153,6 +160,7 @@ struct brw_program_instruction {
     unsigned inst_offset;
     union {
 	struct brw_instruction gen;
+	struct relocatable_instruction reloc;
 	struct label_instruction label;
     } instruction;
     struct brw_program_instruction *next;
@@ -169,6 +177,11 @@ static inline char *label_name(struct brw_program_instruction *i)
     return i->instruction.label.name;
 }
 
+static inline bool is_relocatable(struct brw_program_instruction *intruction)
+{
+    return intruction->type == GEN4ASM_INSTRUCTION_GEN_RELOCATABLE;
+}
+
 /**
  * This structure is a list of instructions.  It is the final output of the
  * parser.