From 34aba9627a8fad20b3b173180e2f3d679dd32293 Mon Sep 17 00:00:00 2001
From: FernandoS27 <fsahmkow27@gmail.com>
Date: Sat, 27 Mar 2021 22:30:24 +0100
Subject: shader: Implement BRX
---
.../frontend/maxwell/control_flow.cpp | 58 ++++++++++++++++++----
1 file changed, 49 insertions(+), 9 deletions(-)
(limited to 'src/shader_recompiler/frontend/maxwell/control_flow.cpp')
diff --git a/src/shader_recompiler/frontend/maxwell/control_flow.cpp b/src/shader_recompiler/frontend/maxwell/control_flow.cpp
index 4f6707fae4..1e9b8e4260 100644
--- a/src/shader_recompiler/frontend/maxwell/control_flow.cpp
+++ b/src/shader_recompiler/frontend/maxwell/control_flow.cpp
@@ -14,6 +14,7 @@
#include "shader_recompiler/exception.h"
#include "shader_recompiler/frontend/maxwell/control_flow.h"
#include "shader_recompiler/frontend/maxwell/decode.h"
+#include "shader_recompiler/frontend/maxwell/indirect_branch_table_track.h"
#include "shader_recompiler/frontend/maxwell/location.h"
namespace Shader::Maxwell::Flow {
@@ -252,9 +253,7 @@ CFG::AnalysisState CFG::AnalyzeInst(Block* block, FunctionId function_id, Locati
const Opcode opcode{Decode(inst.raw)};
switch (opcode) {
case Opcode::BRA:
- case Opcode::BRX:
case Opcode::JMP:
- case Opcode::JMX:
case Opcode::RET:
if (!AnalyzeBranch(block, function_id, pc, inst, opcode)) {
return AnalysisState::Continue;
@@ -264,10 +263,6 @@ CFG::AnalysisState CFG::AnalyzeInst(Block* block, FunctionId function_id, Locati
case Opcode::JMP:
AnalyzeBRA(block, function_id, pc, inst, IsAbsoluteJump(opcode));
break;
- case Opcode::BRX:
- case Opcode::JMX:
- AnalyzeBRX(block, pc, inst, IsAbsoluteJump(opcode));
- break;
case Opcode::RET:
block->end_class = EndClass::Return;
break;
@@ -302,6 +297,9 @@ CFG::AnalysisState CFG::AnalyzeInst(Block* block, FunctionId function_id, Locati
case Opcode::SSY:
block->stack.Push(OpcodeToken(opcode), BranchOffset(pc, inst));
return AnalysisState::Continue;
+ case Opcode::BRX:
+ case Opcode::JMX:
+ return AnalyzeBRX(block, pc, inst, IsAbsoluteJump(opcode), function_id);
case Opcode::EXIT:
return AnalyzeEXIT(block, function_id, pc, inst);
case Opcode::PRET:
@@ -407,8 +405,46 @@ void CFG::AnalyzeBRA(Block* block, FunctionId function_id, Location pc, Instruct
block->branch_true = AddLabel(block, block->stack, bra_pc, function_id);
}
-void CFG::AnalyzeBRX(Block*, Location, Instruction, bool is_absolute) {
- throw NotImplementedException("{}", is_absolute ? "JMX" : "BRX");
+CFG::AnalysisState CFG::AnalyzeBRX(Block* block, Location pc, Instruction inst, bool is_absolute,
+ FunctionId function_id) {
+ const std::optional brx_table{TrackIndirectBranchTable(env, pc, block->begin)};
+ if (!brx_table) {
+ TrackIndirectBranchTable(env, pc, block->begin);
+ throw NotImplementedException("Failed to track indirect branch");
+ }
+ const IR::FlowTest flow_test{inst.branch.flow_test};
+ const Predicate pred{inst.Pred()};
+ if (flow_test != IR::FlowTest::T || pred != Predicate{true}) {
+ throw NotImplementedException("Conditional indirect branch");
+ }
+ std::vector<u32> targets;
+ targets.reserve(brx_table->num_entries);
+ for (u32 i = 0; i < brx_table->num_entries; ++i) {
+ u32 target{env.ReadCbufValue(brx_table->cbuf_index, brx_table->cbuf_offset + i * 4)};
+ if (!is_absolute) {
+ target += pc.Offset();
+ }
+ target += brx_table->branch_offset;
+ target += 8;
+ targets.push_back(target);
+ }
+ std::ranges::sort(targets);
+ targets.erase(std::unique(targets.begin(), targets.end()), targets.end());
+
+ block->indirect_branches.reserve(targets.size());
+ for (const u32 target : targets) {
+ Block* const branch{AddLabel(block, block->stack, target, function_id)};
+ block->indirect_branches.push_back(branch);
+ }
+ block->cond = IR::Condition{true};
+ block->end = pc + 1;
+ block->end_class = EndClass::IndirectBranch;
+ block->branch_reg = brx_table->branch_reg;
+ block->branch_offset = brx_table->branch_offset + 8;
+ if (!is_absolute) {
+ block->branch_offset += pc.Offset();
+ }
+ return AnalysisState::Branch;
}
CFG::AnalysisState CFG::AnalyzeEXIT(Block* block, FunctionId function_id, Location pc,
@@ -449,7 +485,6 @@ Block* CFG::AddLabel(Block* block, Stack stack, Location pc, FunctionId function
// Block already exists and it has been visited
return &*it;
}
- // TODO: FIX DANGLING BLOCKS
Block* const new_block{block_pool.Create(Block{
.begin{pc},
.end{pc},
@@ -494,6 +529,11 @@ std::string CFG::Dot() const {
add_branch(block.branch_false, false);
}
break;
+ case EndClass::IndirectBranch:
+ for (Block* const branch : block.indirect_branches) {
+ add_branch(branch, false);
+ }
+ break;
case EndClass::Call:
dot += fmt::format("\t\t{}->N{};\n", name, node_uid);
dot += fmt::format("\t\tN{}->{};\n", node_uid, NameOf(*block.return_block));
--
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