mirror of
https://github.com/KhronosGroup/SPIRV-Tools
synced 2024-11-25 04:50:04 +00:00
Structured switch checks
Fixes #491 * Basic blocks now have a link to the terminator * Check all case sepecific rules * Missing check for branching into the middle of a case (#1618)
This commit is contained in:
Alan Baker
parent
4f866abfd8
commit
ea7239fa73
@ -37,6 +37,8 @@ enum BlockType : uint32_t {
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kBlockTypeCOUNT ///< Total number of block types. (must be the last element)
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};
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class Instruction;
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// This class represents a basic block in a SPIR-V module
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class BasicBlock {
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public:
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@ -107,6 +109,12 @@ class BasicBlock {
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/// Ends the block without a successor
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void RegisterBranchInstruction(SpvOp branch_instruction);
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/// Registers the terminator instruction for the block.
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void set_terminator(const Instruction* t) { terminator_ = t; }
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/// Returns the terminator instruction for the block.
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const Instruction* terminator() const { return terminator_; }
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/// Adds @p next BasicBlocks as successors of this BasicBlock
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void RegisterSuccessors(
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const std::vector<BasicBlock*>& next = std::vector<BasicBlock*>());
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@ -209,6 +217,9 @@ class BasicBlock {
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/// True if the block is reachable in the CFG
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bool reachable_;
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/// Terminator of this block.
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const Instruction* terminator_;
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};
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/// @brief Returns true if the iterators point to the same element or if both
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@ -409,6 +409,11 @@ void ValidationState_t::RegisterInstruction(
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if (in_function_body()) {
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ordered_instructions_.emplace_back(&inst, ¤t_function(),
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current_function().current_block());
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if (in_block() &&
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spvOpcodeIsBlockTerminator(static_cast<SpvOp>(inst.opcode))) {
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current_function().current_block()->set_terminator(
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&ordered_instructions_.back());
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}
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} else {
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ordered_instructions_.emplace_back(&inst, nullptr, nullptr);
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}
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@ -167,6 +167,153 @@ string ConstructErrorString(const Construct& construct,
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exit_string;
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}
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// Finds the fall through case construct of |target_block| and records it in
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// |case_fall_through|. Returns SPV_ERROR_INVALID_CFG if the case construct
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// headed by |target_block| branches to multiple case constructs.
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spv_result_t FindCaseFallThrough(
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const ValidationState_t& _, const BasicBlock* target_block,
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uint32_t* case_fall_through, const BasicBlock* merge,
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const std::unordered_set<uint32_t>& case_targets) {
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std::vector<const BasicBlock*> stack;
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stack.push_back(target_block);
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std::unordered_set<const BasicBlock*> visited;
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while (!stack.empty()) {
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const auto block = stack.back();
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stack.pop_back();
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if (block == merge) continue;
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if (!visited.insert(block).second) continue;
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if (target_block->reachable() && block->reachable() &&
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target_block->dominates(*block)) {
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// Still in the case construct.
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for (auto successor : *block->successors()) {
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stack.push_back(successor);
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}
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} else {
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// Exiting the case construct to non-merge block.
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if (!case_targets.count(block->id())) {
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continue;
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}
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if (*case_fall_through == 0u) {
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*case_fall_through = block->id();
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} else if (*case_fall_through != block->id()) {
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// Case construct has at most one branch to another case construct.
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return _.diag(SPV_ERROR_INVALID_CFG)
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<< "Case construct that targets "
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<< _.getIdName(target_block->id())
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<< " has branches to multiple other case construct targets "
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<< _.getIdName(*case_fall_through) << " and "
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<< _.getIdName(block->id());
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}
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}
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}
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return SPV_SUCCESS;
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}
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spv_result_t StructuredSwitchChecks(const ValidationState_t& _,
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const Function& function,
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const Instruction* switch_inst,
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const BasicBlock* header,
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const BasicBlock* merge) {
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std::unordered_set<uint32_t> case_targets;
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for (uint32_t i = 1; i < switch_inst->operands().size(); i += 2) {
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uint32_t target = switch_inst->GetOperandAs<uint32_t>(i);
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if (target != merge->id()) case_targets.insert(target);
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}
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// Tracks how many times each case construct is targeted by another case
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// construct.
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std::map<uint32_t, uint32_t> num_fall_through_targeted;
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uint32_t default_case_fall_through = 0u;
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uint32_t default_target = switch_inst->GetOperandAs<uint32_t>(1u);
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std::unordered_set<uint32_t> seen;
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for (uint32_t i = 1; i < switch_inst->operands().size(); i += 2) {
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uint32_t target = switch_inst->GetOperandAs<uint32_t>(i);
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if (target == merge->id()) continue;
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if (!seen.insert(target).second) continue;
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const auto target_block = function.GetBlock(target).first;
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// OpSwitch must dominate all its case constructs.
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if (header->reachable() && target_block->reachable() &&
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!header->dominates(*target_block)) {
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return _.diag(SPV_ERROR_INVALID_CFG)
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<< "Selection header " << _.getIdName(header->id())
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<< " does not dominate its case construct " << _.getIdName(target);
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}
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uint32_t case_fall_through = 0u;
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if (auto error = FindCaseFallThrough(_, target_block, &case_fall_through,
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merge, case_targets)) {
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return error;
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}
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// Track how many time the fall through case has been targeted.
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if (case_fall_through != 0u) {
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auto where = num_fall_through_targeted.lower_bound(case_fall_through);
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if (where == num_fall_through_targeted.end() ||
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where->first != case_fall_through) {
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num_fall_through_targeted.insert(where,
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std::make_pair(case_fall_through, 1));
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} else {
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where->second++;
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}
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}
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if (case_fall_through == default_target) {
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case_fall_through = default_case_fall_through;
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}
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if (case_fall_through != 0u) {
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bool is_default = i == 1;
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if (is_default) {
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default_case_fall_through = case_fall_through;
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} else {
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// Allow code like:
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// case x:
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// case y:
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// ...
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// case z:
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//
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// Where x and y target the same block and fall through to z.
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uint32_t j = i;
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while ((j + 2 < switch_inst->operands().size()) &&
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target == switch_inst->GetOperandAs<uint32_t>(j + 2)) {
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j += 2;
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}
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// If Target T1 branches to Target T2, or if Target T1 branches to the
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// Default target and the Default target branches to Target T2, then T1
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// must immediately precede T2 in the list of OpSwitch Target operands.
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if ((switch_inst->operands().size() < j + 2) ||
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(case_fall_through != switch_inst->GetOperandAs<uint32_t>(j + 2))) {
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return _.diag(SPV_ERROR_INVALID_CFG)
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<< "Case construct that targets " << _.getIdName(target)
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<< " has branches to the case construct that targets "
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<< _.getIdName(case_fall_through)
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<< ", but does not immediately precede it in the "
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"OpSwitch's "
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"target list";
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}
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}
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}
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}
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// Each case construct must be branched to by at most one other case
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// construct.
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for (const auto& pair : num_fall_through_targeted) {
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if (pair.second > 1) {
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return _.diag(SPV_ERROR_INVALID_CFG)
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<< "Multiple case constructs have branches to the case construct "
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"that targets "
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<< _.getIdName(pair.first);
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}
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}
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return SPV_SUCCESS;
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}
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spv_result_t StructuredControlFlowChecks(
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const ValidationState_t& _, Function* function,
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const vector<pair<uint32_t, uint32_t>>& back_edges) {
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@ -261,16 +408,15 @@ spv_result_t StructuredControlFlowChecks(
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}
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}
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// TODO(umar): an OpSwitch block dominates all its defined case
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// constructs
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// TODO(umar): each case construct has at most one branch to another
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// case construct
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// TODO(umar): each case construct is branched to by at most one other
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// case construct
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// TODO(umar): if Target T1 branches to Target T2, or if Target T1
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// branches to the Default and the Default branches to Target T2, then
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// T1 must immediately precede T2 in the list of the OpSwitch Target
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// operands
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// Checks rules for case constructs.
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if (construct.type() == ConstructType::kSelection &&
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header->terminator()->opcode() == SpvOpSwitch) {
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const auto terminator = header->terminator();
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if (auto error =
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StructuredSwitchChecks(_, *function, terminator, header, merge)) {
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return error;
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}
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}
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}
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return SPV_SUCCESS;
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}
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@ -1450,6 +1450,289 @@ OpFunctionEnd
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"selection header <ID>"));
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}
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/// TODO(umar): Switch instructions
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TEST_F(ValidateCFG, SwitchDefaultOnly) {
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std::string text = R"(
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OpCapability Shader
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OpCapability Linkage
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OpMemoryModel Logical GLSL450
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%1 = OpTypeVoid
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%2 = OpTypeInt 32 0
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%3 = OpConstant %2 0
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%4 = OpTypeFunction %1
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%5 = OpFunction %1 None %4
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%6 = OpLabel
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OpSelectionMerge %7 None
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OpSwitch %3 %7
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%7 = OpLabel
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OpReturn
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OpFunctionEnd
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)";
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CompileSuccessfully(text);
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ASSERT_EQ(SPV_SUCCESS, ValidateInstructions());
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}
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TEST_F(ValidateCFG, SwitchSingleCase) {
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std::string text = R"(
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OpCapability Shader
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OpCapability Linkage
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OpMemoryModel Logical GLSL450
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%1 = OpTypeVoid
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%2 = OpTypeInt 32 0
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%3 = OpConstant %2 0
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%4 = OpTypeFunction %1
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%5 = OpFunction %1 None %4
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%6 = OpLabel
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OpSelectionMerge %7 None
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OpSwitch %3 %7 0 %8
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%8 = OpLabel
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OpBranch %7
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%7 = OpLabel
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OpReturn
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OpFunctionEnd
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)";
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CompileSuccessfully(text);
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ASSERT_EQ(SPV_SUCCESS, ValidateInstructions());
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}
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TEST_F(ValidateCFG, MultipleFallThroughBlocks) {
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std::string text = R"(
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OpCapability Shader
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OpCapability Linkage
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OpMemoryModel Logical GLSL450
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%1 = OpTypeVoid
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%2 = OpTypeInt 32 0
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%3 = OpConstant %2 0
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%4 = OpTypeFunction %1
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%5 = OpTypeBool
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%6 = OpConstantTrue %5
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%7 = OpFunction %1 None %4
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%8 = OpLabel
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OpSelectionMerge %9 None
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OpSwitch %3 %10 0 %11 1 %12
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%10 = OpLabel
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OpBranchConditional %6 %11 %12
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%11 = OpLabel
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OpBranch %9
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%12 = OpLabel
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OpBranch %9
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%9 = OpLabel
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OpReturn
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OpFunctionEnd
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)";
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CompileSuccessfully(text);
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ASSERT_EQ(SPV_ERROR_INVALID_CFG, ValidateInstructions());
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EXPECT_THAT(
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getDiagnosticString(),
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HasSubstr(
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"Case construct that targets 10 has branches to multiple other case "
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"construct targets 12 and 11"));
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}
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TEST_F(ValidateCFG, MultipleFallThroughToDefault) {
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std::string text = R"(
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OpCapability Shader
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OpCapability Linkage
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OpMemoryModel Logical GLSL450
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%1 = OpTypeVoid
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%2 = OpTypeInt 32 0
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%3 = OpConstant %2 0
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%4 = OpTypeFunction %1
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%5 = OpTypeBool
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%6 = OpConstantTrue %5
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%7 = OpFunction %1 None %4
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%8 = OpLabel
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OpSelectionMerge %9 None
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OpSwitch %3 %10 0 %11 1 %12
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%10 = OpLabel
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OpBranch %9
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%11 = OpLabel
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OpBranch %10
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%12 = OpLabel
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OpBranch %10
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%9 = OpLabel
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OpReturn
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OpFunctionEnd
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)";
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CompileSuccessfully(text);
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ASSERT_EQ(SPV_ERROR_INVALID_CFG, ValidateInstructions());
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EXPECT_THAT(
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getDiagnosticString(),
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HasSubstr("Multiple case constructs have branches to the case construct "
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"that targets 10"));
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}
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TEST_F(ValidateCFG, MultipleFallThroughToNonDefault) {
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std::string text = R"(
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OpCapability Shader
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OpCapability Linkage
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OpMemoryModel Logical GLSL450
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%1 = OpTypeVoid
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%2 = OpTypeInt 32 0
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%3 = OpConstant %2 0
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%4 = OpTypeFunction %1
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%5 = OpTypeBool
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%6 = OpConstantTrue %5
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%7 = OpFunction %1 None %4
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%8 = OpLabel
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OpSelectionMerge %9 None
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OpSwitch %3 %10 0 %11 1 %12
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%10 = OpLabel
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OpBranch %12
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%11 = OpLabel
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OpBranch %12
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%12 = OpLabel
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OpBranch %9
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%9 = OpLabel
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OpReturn
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OpFunctionEnd
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)";
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CompileSuccessfully(text);
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ASSERT_EQ(SPV_ERROR_INVALID_CFG, ValidateInstructions());
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EXPECT_THAT(
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getDiagnosticString(),
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HasSubstr("Multiple case constructs have branches to the case construct "
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"that targets 12"));
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}
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TEST_F(ValidateCFG, DuplicateTargetWithFallThrough) {
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std::string text = R"(
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OpCapability Shader
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OpCapability Linkage
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OpMemoryModel Logical GLSL450
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%1 = OpTypeVoid
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%2 = OpTypeInt 32 0
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%3 = OpConstant %2 0
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%4 = OpTypeFunction %1
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%5 = OpTypeBool
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%6 = OpConstantTrue %5
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%7 = OpFunction %1 None %4
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%8 = OpLabel
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OpSelectionMerge %9 None
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OpSwitch %3 %10 0 %10 1 %11
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%10 = OpLabel
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OpBranch %11
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%11 = OpLabel
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OpBranch %9
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%9 = OpLabel
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OpReturn
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OpFunctionEnd
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)";
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CompileSuccessfully(text);
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ASSERT_EQ(SPV_SUCCESS, ValidateInstructions());
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}
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TEST_F(ValidateCFG, WrongOperandList) {
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std::string text = R"(
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OpCapability Shader
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OpCapability Linkage
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OpMemoryModel Logical GLSL450
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%1 = OpTypeVoid
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%2 = OpTypeInt 32 0
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%3 = OpConstant %2 0
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%4 = OpTypeFunction %1
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%5 = OpTypeBool
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%6 = OpConstantTrue %5
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%7 = OpFunction %1 None %4
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%8 = OpLabel
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OpSelectionMerge %9 None
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OpSwitch %3 %10 0 %11 1 %12
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%10 = OpLabel
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OpBranch %9
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%12 = OpLabel
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OpBranch %11
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%11 = OpLabel
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OpBranch %9
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%9 = OpLabel
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OpReturn
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OpFunctionEnd
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)";
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CompileSuccessfully(text);
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ASSERT_EQ(SPV_ERROR_INVALID_CFG, ValidateInstructions());
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EXPECT_THAT(
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getDiagnosticString(),
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HasSubstr("Case construct that targets 12 has branches to the case "
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"construct that targets 11, but does not immediately "
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"precede it in the OpSwitch's target list"));
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}
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TEST_F(ValidateCFG, WrongOperandListThroughDefault) {
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std::string text = R"(
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OpCapability Shader
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OpCapability Linkage
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OpMemoryModel Logical GLSL450
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%1 = OpTypeVoid
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%2 = OpTypeInt 32 0
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%3 = OpConstant %2 0
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%4 = OpTypeFunction %1
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%5 = OpTypeBool
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%6 = OpConstantTrue %5
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%7 = OpFunction %1 None %4
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%8 = OpLabel
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OpSelectionMerge %9 None
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OpSwitch %3 %10 0 %11 1 %12
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%10 = OpLabel
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OpBranch %11
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%12 = OpLabel
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OpBranch %10
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%11 = OpLabel
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OpBranch %9
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%9 = OpLabel
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OpReturn
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OpFunctionEnd
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)";
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CompileSuccessfully(text);
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ASSERT_EQ(SPV_ERROR_INVALID_CFG, ValidateInstructions());
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EXPECT_THAT(
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getDiagnosticString(),
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HasSubstr("Case construct that targets 12 has branches to the case "
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"construct that targets 11, but does not immediately "
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"precede it in the OpSwitch's target list"));
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}
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TEST_F(ValidateCFG, WrongOperandListNotLast) {
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std::string text = R"(
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OpCapability Shader
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OpCapability Linkage
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OpMemoryModel Logical GLSL450
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%1 = OpTypeVoid
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%2 = OpTypeInt 32 0
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%3 = OpConstant %2 0
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%4 = OpTypeFunction %1
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%5 = OpTypeBool
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%6 = OpConstantTrue %5
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%7 = OpFunction %1 None %4
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%8 = OpLabel
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OpSelectionMerge %9 None
|
||||
OpSwitch %3 %10 0 %11 1 %12 2 %13
|
||||
%10 = OpLabel
|
||||
OpBranch %9
|
||||
%12 = OpLabel
|
||||
OpBranch %11
|
||||
%11 = OpLabel
|
||||
OpBranch %9
|
||||
%13 = OpLabel
|
||||
OpBranch %9
|
||||
%9 = OpLabel
|
||||
OpReturn
|
||||
OpFunctionEnd
|
||||
)";
|
||||
|
||||
CompileSuccessfully(text);
|
||||
ASSERT_EQ(SPV_ERROR_INVALID_CFG, ValidateInstructions());
|
||||
EXPECT_THAT(
|
||||
getDiagnosticString(),
|
||||
HasSubstr("Case construct that targets 12 has branches to the case "
|
||||
"construct that targets 11, but does not immediately "
|
||||
"precede it in the OpSwitch's target list"));
|
||||
}
|
||||
|
||||
/// TODO(umar): Nested CFG constructs
|
||||
} // namespace
|
||||
|
||||
Loading…
Reference in New Issue
Block a user