1 files changed, 331 insertions, 0 deletions
diff --git a/src/mesa/drivers/dri/r300/compiler/radeon_emulate_branches.c b/src/mesa/drivers/dri/r300/compiler/radeon_emulate_branches.c
new file mode 100644
index 0000000000..d889612f4f
--- /dev/null
+++ b/src/mesa/drivers/dri/r300/compiler/radeon_emulate_branches.c
@@ -0,0 +1,331 @@
+/*
+ * Copyright 2009 Nicolai Hähnle <nhaehnle@gmail.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * on the rights to use, copy, modify, merge, publish, distribute, sub
+ * license, and/or sell copies of the Software, and to permit persons to whom
+ * the Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHOR(S) AND/OR THEIR SUPPLIERS BE LIABLE FOR ANY CLAIM,
+ * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+ * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+ * USE OR OTHER DEALINGS IN THE SOFTWARE. */
+
+#include "radeon_emulate_branches.h"
+
+#include <stdio.h>
+
+#include "radeon_compiler.h"
+#include "radeon_dataflow.h"
+
+#define VERBOSE 0
+
+#define DBG(...) do { if (VERBOSE) fprintf(stderr, __VA_ARGS__); } while(0)
+
+
+struct proxy_info {
+	unsigned int Proxied:1;
+	unsigned int Index:RC_REGISTER_INDEX_BITS;
+};
+
+struct register_proxies {
+	struct proxy_info Temporary[RC_REGISTER_MAX_INDEX];
+};
+
+struct branch_info {
+	struct rc_instruction * If;
+	struct rc_instruction * Else;
+};
+
+struct emulate_branch_state {
+	struct radeon_compiler * C;
+
+	struct branch_info * Branches;
+	unsigned int BranchCount;
+	unsigned int BranchReserved;
+};
+
+
+static void handle_if(struct emulate_branch_state * s, struct rc_instruction * inst)
+{
+	memory_pool_array_reserve(&s->C->Pool, struct branch_info,
+			s->Branches, s->BranchCount, s->BranchReserved, 1);
+
+	DBG("%s\n", __FUNCTION__);
+
+	struct branch_info * branch = &s->Branches[s->BranchCount++];
+	memset(branch, 0, sizeof(struct branch_info));
+	branch->If = inst;
+
+	/* Make a safety copy of the decision register, because we will need
+	 * it at ENDIF time and it might be overwritten in both branches. */
+	struct rc_instruction * inst_mov = rc_insert_new_instruction(s->C, inst->Prev);
+	inst_mov->U.I.Opcode = RC_OPCODE_MOV;
+	inst_mov->U.I.DstReg.File = RC_FILE_TEMPORARY;
+	inst_mov->U.I.DstReg.Index = rc_find_free_temporary(s->C);
+	inst_mov->U.I.DstReg.WriteMask = RC_MASK_X;
+	inst_mov->U.I.SrcReg[0] = inst->U.I.SrcReg[0];
+
+	inst->U.I.SrcReg[0].File = RC_FILE_TEMPORARY;
+	inst->U.I.SrcReg[0].Index = inst_mov->U.I.DstReg.Index;
+	inst->U.I.SrcReg[0].Swizzle = 0;
+	inst->U.I.SrcReg[0].Abs = 0;
+	inst->U.I.SrcReg[0].Negate = 0;
+}
+
+static void handle_else(struct emulate_branch_state * s, struct rc_instruction * inst)
+{
+	if (!s->BranchCount) {
+		rc_error(s->C, "Encountered ELSE outside of branches");
+		return;
+	}
+
+	DBG("%s\n", __FUNCTION__);
+
+	struct branch_info * branch = &s->Branches[s->BranchCount - 1];
+	branch->Else = inst;
+}
+
+
+struct state_and_proxies {
+	struct emulate_branch_state * S;
+	struct register_proxies * Proxies;
+};
+
+static struct proxy_info * get_proxy_info(struct state_and_proxies * sap,
+			rc_register_file file, unsigned int index)
+{
+	if (file == RC_FILE_TEMPORARY) {
+		return &sap->Proxies->Temporary[index];
+	} else {
+		return 0;
+	}
+}
+
+static void scan_write(void * userdata, struct rc_instruction * inst,
+		rc_register_file file, unsigned int index, unsigned int comp)
+{
+	struct state_and_proxies * sap = userdata;
+	struct proxy_info * proxy = get_proxy_info(sap, file, index);
+
+	if (proxy && !proxy->Proxied) {
+		proxy->Proxied = 1;
+		proxy->Index = rc_find_free_temporary(sap->S->C);
+	}
+}
+
+static void remap_proxy_function(void * userdata, struct rc_instruction * inst,
+		rc_register_file * pfile, unsigned int * pindex)
+{
+	struct state_and_proxies * sap = userdata;
+	struct proxy_info * proxy = get_proxy_info(sap, *pfile, *pindex);
+
+	if (proxy && proxy->Proxied) {
+		*pfile = RC_FILE_TEMPORARY;
+		*pindex = proxy->Index;
+	}
+}
+
+/**
+ * Redirect all writes in the instruction range [begin, end) to proxy
+ * temporary registers.
+ */
+static void allocate_and_insert_proxies(struct emulate_branch_state * s,
+		struct register_proxies * proxies,
+		struct rc_instruction * begin,
+		struct rc_instruction * end)
+{
+	struct state_and_proxies sap;
+
+	sap.S = s;
+	sap.Proxies = proxies;
+
+	for(struct rc_instruction * inst = begin; inst != end; inst = inst->Next) {
+		rc_for_all_writes(inst, scan_write, &sap);
+		rc_remap_registers(inst, remap_proxy_function, &sap);
+	}
+
+	for(unsigned int index = 0; index < RC_REGISTER_MAX_INDEX; ++index) {
+		if (proxies->Temporary[index].Proxied) {
+			struct rc_instruction * inst_mov = rc_insert_new_instruction(s->C, begin->Prev);
+			inst_mov->U.I.Opcode = RC_OPCODE_MOV;
+			inst_mov->U.I.DstReg.File = RC_FILE_TEMPORARY;
+			inst_mov->U.I.DstReg.Index = proxies->Temporary[index].Index;
+			inst_mov->U.I.DstReg.WriteMask = RC_MASK_XYZW;
+			inst_mov->U.I.SrcReg[0].File = RC_FILE_TEMPORARY;
+			inst_mov->U.I.SrcReg[0].Index = index;
+		}
+	}
+}
+
+
+static void inject_cmp(struct emulate_branch_state * s,
+		struct rc_instruction * inst_if,
+		struct rc_instruction * inst_endif,
+		rc_register_file file, unsigned int index,
+		struct proxy_info ifproxy,
+		struct proxy_info elseproxy)
+{
+	struct rc_instruction * inst_cmp = rc_insert_new_instruction(s->C, inst_endif);
+	inst_cmp->U.I.Opcode = RC_OPCODE_CMP;
+	inst_cmp->U.I.DstReg.File = file;
+	inst_cmp->U.I.DstReg.Index = index;
+	inst_cmp->U.I.DstReg.WriteMask = RC_MASK_XYZW;
+	inst_cmp->U.I.SrcReg[0] = inst_if->U.I.SrcReg[0];
+	inst_cmp->U.I.SrcReg[0].Abs = 1;
+	inst_cmp->U.I.SrcReg[0].Negate = RC_MASK_XYZW;
+	inst_cmp->U.I.SrcReg[1].File = RC_FILE_TEMPORARY;
+	inst_cmp->U.I.SrcReg[1].Index = ifproxy.Proxied ? ifproxy.Index : index;
+	inst_cmp->U.I.SrcReg[2].File = RC_FILE_TEMPORARY;
+	inst_cmp->U.I.SrcReg[2].Index = elseproxy.Proxied ? elseproxy.Index : index;
+}
+
+static void handle_endif(struct emulate_branch_state * s, struct rc_instruction * inst)
+{
+	if (!s->BranchCount) {
+		rc_error(s->C, "Encountered ENDIF outside of branches");
+		return;
+	}
+
+	DBG("%s\n", __FUNCTION__);
+
+	struct branch_info * branch = &s->Branches[s->BranchCount - 1];
+	struct register_proxies IfProxies;
+	struct register_proxies ElseProxies;
+
+	memset(&IfProxies, 0, sizeof(IfProxies));
+	memset(&ElseProxies, 0, sizeof(ElseProxies));
+
+	allocate_and_insert_proxies(s, &IfProxies, branch->If->Next, branch->Else ? branch->Else : inst);
+
+	if (branch->Else)
+		allocate_and_insert_proxies(s, &ElseProxies, branch->Else->Next, inst);
+
+	/* Insert the CMP instructions at the end. */
+	for(unsigned int index = 0; index < RC_REGISTER_MAX_INDEX; ++index) {
+		if (IfProxies.Temporary[index].Proxied || ElseProxies.Temporary[index].Proxied) {
+			inject_cmp(s, branch->If, inst, RC_FILE_TEMPORARY, index,
+					IfProxies.Temporary[index], ElseProxies.Temporary[index]);
+		}
+	}
+
+	/* Remove all traces of the branch instructions */
+	rc_remove_instruction(branch->If);
+	if (branch->Else)
+		rc_remove_instruction(branch->Else);
+	rc_remove_instruction(inst);
+
+	s->BranchCount--;
+
+	if (VERBOSE) {
+		DBG("Program after ENDIF handling:\n");
+		rc_print_program(&s->C->Program);
+	}
+}
+
+
+struct remap_output_data {
+	unsigned int Output:RC_REGISTER_INDEX_BITS;
+	unsigned int Temporary:RC_REGISTER_INDEX_BITS;
+};
+
+static void remap_output_function(void * userdata, struct rc_instruction * inst,
+		rc_register_file * pfile, unsigned int * pindex)
+{
+	struct remap_output_data * data = userdata;
+
+	if (*pfile == RC_FILE_OUTPUT && *pindex == data->Output) {
+		*pfile = RC_FILE_TEMPORARY;
+		*pindex = data->Temporary;
+	}
+}
+
+
+/**
+ * Output registers cannot be read from and so cannot be dealt with like
+ * temporary registers.
+ *
+ * We do the simplest thing: If an output registers is written within
+ * a branch, then *all* writes to this register are proxied to a
+ * temporary register, and a final MOV is appended to the end of
+ * the program.
+ */
+static void fix_output_writes(struct emulate_branch_state * s, struct rc_instruction * inst)
+{
+	if (!s->BranchCount)
+		return;
+
+	const struct rc_opcode_info * opcode = rc_get_opcode_info(inst->U.I.Opcode);
+
+	if (!opcode->HasDstReg)
+		return;
+
+	if (inst->U.I.DstReg.File == RC_FILE_OUTPUT) {
+		struct remap_output_data remap;
+
+		remap.Output = inst->U.I.DstReg.Index;
+		remap.Temporary = rc_find_free_temporary(s->C);
+
+		for(struct rc_instruction * inst = s->C->Program.Instructions.Next;
+		    inst != &s->C->Program.Instructions;
+		    inst = inst->Next) {
+			rc_remap_registers(inst, &remap_output_function, &remap);
+		}
+
+		struct rc_instruction * inst_mov = rc_insert_new_instruction(s->C, s->C->Program.Instructions.Prev);
+		inst_mov->U.I.Opcode = RC_OPCODE_MOV;
+		inst_mov->U.I.DstReg.File = RC_FILE_OUTPUT;
+		inst_mov->U.I.DstReg.Index = remap.Output;
+		inst_mov->U.I.DstReg.WriteMask = RC_MASK_XYZW;
+		inst_mov->U.I.SrcReg[0].File = RC_FILE_TEMPORARY;
+		inst_mov->U.I.SrcReg[0].Index = remap.Temporary;
+	}
+}
+
+/**
+ * Remove branch instructions; instead, execute both branches
+ * on different register sets and choose between their results
+ * using CMP instructions in place of the original ENDIF.
+ */
+void rc_emulate_branches(struct radeon_compiler * c)
+{
+	struct emulate_branch_state s;
+
+	memset(&s, 0, sizeof(s));
+	s.C = c;
+
+	/* Untypical loop because we may remove the current instruction */
+	struct rc_instruction * ptr = c->Program.Instructions.Next;
+	while(ptr != &c->Program.Instructions) {
+		struct rc_instruction * inst = ptr;
+		ptr = ptr->Next;
+
+		if (inst->Type == RC_INSTRUCTION_NORMAL) {
+			switch(inst->U.I.Opcode) {
+			case RC_OPCODE_IF:
+				handle_if(&s, inst);
+				break;
+			case RC_OPCODE_ELSE:
+				handle_else(&s, inst);
+				break;
+			case RC_OPCODE_ENDIF:
+				handle_endif(&s, inst);
+				break;
+			default:
+				fix_output_writes(&s, inst);
+				break;
+			}
+		} else {
+			rc_error(c, "%s: unhandled instruction type\n", __FUNCTION__);
+		}
+	}
+}