r300: Fix fragment program instruction pairing and register allocation

There were a number of bugs related to the pairing of vector and scalar
operations where swizzles ended up using the wrong source register,
or an instruction was moved forward and ended up overwriting an aliased
register.

The new algorithm for register allocation is quite conservative and may
run out of registers before necessary. On the plus side, It Just Works.

Pairing is done whenever possible, and in more cases than before, so
in practice this change should be a net win.

1 files changed, 70 insertions, 24 deletions

diff --git a/src/mesa/drivers/dri/r300/r300_context.h b/src/mesa/drivers/dri/r300/r300_context.h
index bd9ed6f170..bc43953ff3 100644
--- a/src/mesa/drivers/dri/r300/r300_context.h
+++ b/src/mesa/drivers/dri/r300/r300_context.h
@@ -647,38 +647,84 @@ struct r300_vertex_program_cont {
 #define PFS_NUM_TEMP_REGS	32
 #define PFS_NUM_CONST_REGS	16
 
-/* Tracking data for Mesa registers */
+/* Mapping Mesa registers to R300 temporaries */
 struct reg_acc {
        int reg;        /* Assigned hw temp */
        unsigned int refcount; /* Number of uses by mesa program */
 };
 
+/**
+ * Describe the current lifetime information for an R300 temporary
+ */
+struct reg_lifetime {
+	/* Index of the first slot where this register is free in the sense
+	   that it can be used as a new destination register.
+	   This is -1 if the register has been assigned to a Mesa register
+	   and the last access to the register has not yet been emitted */
+	int free;
+	
+	/* Index of the first slot where this register is currently reserved.
+	   This is used to stop e.g. a scalar operation from being moved
+	   before the allocation time of a register that was first allocated
+	   for a vector operation. */
+	int reserved;
+	
+	/* Index of the first slot in which the register can be used as a
+	   source without losing the value that is written by the last
+	   emitted instruction that writes to the register */
+	int vector_valid;
+	int scalar_valid;
+};
+
+
+/**
+ * Store usage information about an ALU instruction slot during the
+ * compilation of a fragment program.
+ */
+#define SLOT_SRC_VECTOR  (1<<0)
+#define SLOT_SRC_SCALAR  (1<<3)
+#define SLOT_SRC_BOTH    (SLOT_SRC_VECTOR | SLOT_SRC_SCALAR)
+#define SLOT_OP_VECTOR   (1<<16)
+#define SLOT_OP_SCALAR   (1<<17)
+#define SLOT_OP_BOTH     (SLOT_OP_VECTOR | SLOT_OP_SCALAR)
+
+struct r300_pfs_compile_slot {
+	/* Bitmask indicating which parts of the slot are used, using SLOT_ constants 
+	   defined above */
+	unsigned int used;
+
+	/* Selected sources */
+	int vsrc[3];
+	int ssrc[3];
+};
+
+/**
+ * Store information during compilation of fragment programs.
+ */
 struct r300_pfs_compile_state {
-       int v_pos, s_pos;       /* highest ALU slots used */
-
-       /* Track some information gathered during opcode
-        * construction.
-        * 
-        * NOTE: Data is only set by the code, and isn't used yet.
-        */
-       struct {
-               int vsrc[3];
-               int ssrc[3];
-               int umask;
-       } slot[PFS_MAX_ALU_INST];
-
-       /* Used to map Mesa's inputs/temps onto hardware temps */
-       int temp_in_use;
-       struct reg_acc temps[PFS_NUM_TEMP_REGS];
-       struct reg_acc inputs[32]; /* don't actually need 32... */
-
-       /* Track usage of hardware temps, for register allocation,
-        * indirection detection, etc. */
-       int hwreg_in_use;
-       GLuint used_in_node;
-       GLuint dest_in_node;
+	int nrslots;       /* number of ALU slots used so far */
+	
+	/* Track which (parts of) slots are already filled with instructions */
+	struct r300_pfs_compile_slot slot[PFS_MAX_ALU_INST];
+	
+	/* Track the validity of R300 temporaries */
+	struct reg_lifetime hwtemps[PFS_NUM_TEMP_REGS];
+	
+	/* Used to map Mesa's inputs/temps onto hardware temps */
+	int temp_in_use;
+	struct reg_acc temps[PFS_NUM_TEMP_REGS];
+	struct reg_acc inputs[32]; /* don't actually need 32... */
+	
+	/* Track usage of hardware temps, for register allocation,
+	 * indirection detection, etc. */
+	GLuint used_in_node;
+	GLuint dest_in_node;
 };
 
+/**
+ * Store everything about a fragment program that is needed
+ * to render with that program.
+ */
 struct r300_fragment_program {
 	struct gl_fragment_program mesa_program;