[PASS] Add GPU IR verifier (apache#1296)

include/tvm/ir_pass.h

@@ -477,6 +477,30 @@ LoweredFunc LowerIntrin(LoweredFunc f, const std::string& target);
  */
 bool VerifyMemory(LoweredFunc func, int device_type);
 
+
+/*!
+ * \brief Verify the correctness of a GPU code
+ *        It will check the whether the amount of memory usage or the number of threads
+ *        in a block exceeds the limit
+ * \param stmt The statement to be checked
+ * \param constraints The dict to specify constraints to check.
+ *        Possible keys are
+ *
+ *        "max_local_memory_per_block": Total amount of local memory per block (in bytes).
+ *        "max_shared_memory_per_block": Total amount of shared memory per block (in bytes).
+ *        "max_thread_per_block": Maximum number of threads per block.
+ *        "max_thread_x": Maximum length of threadIdx.x.
+ *        "max_thread_y": Maximum length of threadIdx.y.
+ *        "max_thread_z": Maximum length of threadIdx.z.
+ *
+ *        If one key is missing in this argument, the pass won't check for that item.
+ * \return valid Whether it is a valid GPU code
+ *
+ */
+bool VerifyGPUCode(Stmt stmt,
+                   Map<std::string, Expr> constraints);
+
+
 }  // namespace ir
 }  // namespace tvm
 

include/tvm/runtime/device_api.h

@@ -23,7 +23,8 @@ enum DeviceAttrKind : int {
   kComputeVersion = 4,
   kDeviceName = 5,
   kMaxClockRate = 6,
-  kMultiProcessorCount = 7
+  kMultiProcessorCount = 7,
+  kMaxThreadDimensions = 8
 };
 
 /*! \brief Number of bytes each allocation must align to */

python/tvm/_ffi/runtime_ctypes.py

@@ -3,6 +3,7 @@
 from __future__ import absolute_import
 
 import ctypes
+import json
 import numpy as np
 from .base import _LIB, check_call
 from .. import _api_internal
@@ -178,6 +179,18 @@ def multi_processor_count(self):
         return _api_internal._GetDeviceAttr(
             self.device_type, self.device_id, 7)
 
+    @property
+    def max_thread_dimensions(self):
+        """Return the maximum size of each thread axis
+
+        Returns
+        -------
+        dims: List of int
+            The maximum length of threadIdx.x, threadIdx.y, threadIdx.z
+        """
+        return json.loads(_api_internal._GetDeviceAttr(
+            self.device_type, self.device_id, 8))
+
     def sync(self):
         """Synchronize until jobs finished at the context."""
         check_call(_LIB.TVMSynchronize(self.device_type, self.device_id, None))

src/api/api_pass.cc

@@ -131,5 +131,6 @@ REGISTER_PASS2(LowerIntrin);
 REGISTER_PASS1(LowerTVMBuiltin);
 REGISTER_PASS1(CombineContextCall);
 REGISTER_PASS2(VerifyMemory);
+REGISTER_PASS2(VerifyGPUCode);
 }  // namespace ir
 }  // namespace tvm

src/pass/verify_gpu_code.cc

@@ -0,0 +1,166 @@
+/*!
+ *  Copyright (c) 2018 by Contributors
+ * \file verify_gpu_code.cc
+ * \brief Verify the correctness of a GPU IR.
+ *        It will check the whether the amount of memory usage or the number of threads
+ *        in a block exceeds the limit
+ */
+
+#include <tvm/api_registry.h>
+#include <tvm/ir.h>
+#include <tvm/ir_visitor.h>
+
+namespace tvm {
+namespace ir {
+
+class GPUCodeVerifier : public IRVisitor {
+ public:
+  bool Verify(tvm::Stmt stmt,
+              int64_t max_local_memory_per_block,
+              int64_t max_shared_memory_per_block,
+              int64_t max_thread_per_block,
+              int64_t max_thread_x,
+              int64_t max_thread_y,
+              int64_t max_thread_z) {
+    max_local_memory_per_block_ = static_cast<size_t>(max_local_memory_per_block);
+    max_shared_memory_per_block_ = static_cast<size_t>(max_shared_memory_per_block);
+    max_thread_per_block_ = static_cast<size_t>(max_thread_per_block);
+    max_thread_x_ = static_cast<size_t>(max_thread_x);
+    max_thread_y_ = static_cast<size_t>(max_thread_y);
+    max_thread_z_ = static_cast<size_t>(max_thread_z);
+
+    Reset_();
+
+    this->Visit(stmt);
+
+    return valid_;
+  }
+
+  void Visit_(const ProducerConsumer *op) {
+    if (nest_level_ == 0) {
+      // enter a new kernel, reset statistics
+      Reset_();
+    }
+
+    if (op->is_producer) {
+      nest_level_++;
+      IRVisitor::Visit_(op);
+      nest_level_--;
+    } else {
+      IRVisitor::Visit_(op);
+    }
+
+    if (nest_level_ == 0) {
+      // exit a kernel, check the validity
+      valid_ &= thread_per_block_ <= max_thread_per_block_;
+
+      valid_ &= local_memory_per_block_ <= max_local_memory_per_block_;
+      valid_ &= shared_memory_per_block_ <= max_shared_memory_per_block_;
+    }
+  }
+
+  void Visit_(const Allocate *op) {
+    IRVisitor::Visit_(op);
+    // visit an allocation of a buffer in shared memory, record its size
+    if (visited_local_buffers_.count(op->buffer_var.get()) != 0) {
+      size_t size = static_cast<size_t>(op->constant_allocation_size());
+      local_memory_per_block_ += size * op->type.bytes();
+    } else if (visited_shared_buffers_.count(op->buffer_var.get()) != 0) {
+      size_t size = static_cast<size_t>(op->constant_allocation_size());
+      shared_memory_per_block_ += size * op->type.bytes();
+    }
+  }
+
+  void Visit_(const AttrStmt *op) {
+    if (op->attr_key == attr::storage_scope) {
+      if (op->value.as<StringImm>()->value == "local") {
+        visited_local_buffers_.insert(op->node.as<tvm::Variable>());
+      } else if (op->value.as<StringImm>()->value == "shared") {
+        visited_shared_buffers_.insert(op->node.as<tvm::Variable>());
+      }
+    } else if (op->attr_key == attr::thread_extent) {
+      VarExpr var = op->node.as<tvm::IterVarNode>()->var;
+      const auto *extent = op->value.as<IntImm>();
+      CHECK(extent);
+
+      // record the number of threads in a block
+      std::string name = var.get()->name_hint;
+      if (name == "threadIdx.x" || name == "threadIdx.y" || name == "threadIdx.z") {
+        if (!visited_threads_.count(name)) {
+          visited_threads_.insert(name);
+          size_t length = static_cast<size_t>(extent->value);
+          thread_per_block_ *= length;
+
+          if (name == "threadIdx.x") {
+            valid_ &= length <= max_thread_x_;
+          } else if (name == "threadIdx.y") {
+            valid_ &= length <= max_thread_y_;
+          } else if (name == "threadIdx.z") {
+            valid_ &= length <= max_thread_z_;
+          }
+        }
+      }
+    }
+    IRVisitor::Visit_(op);
+  }
+
+ private:
+  int nest_level_{0};
+
+  std::unordered_set<const tvm::Variable *> visited_local_buffers_;
+  std::unordered_set<const tvm::Variable *> visited_shared_buffers_;
+  std::unordered_set<std::string> visited_threads_;
+
+  size_t local_memory_per_block_;
+  size_t shared_memory_per_block_;
+  size_t thread_per_block_;
+
+  size_t max_local_memory_per_block_;
+  size_t max_shared_memory_per_block_;
+  size_t max_thread_per_block_;
+  size_t max_thread_x_, max_thread_y_, max_thread_z_;
+
+  bool valid_{true};
+
+  void Reset_() {
+    visited_local_buffers_.clear();
+    visited_shared_buffers_.clear();
+    local_memory_per_block_ = 0;
+    shared_memory_per_block_ = 0;
+
+    visited_threads_.clear();
+    thread_per_block_ = 1;
+  }
+};
+
+bool VerifyGPUCode(Stmt stmt,
+                   Map<std::string, Expr> constraints) {
+  GPUCodeVerifier verifier;
+
+  auto get_int = [&constraints](std::string key, int64_t def) {
+    auto iter = constraints.find(key);
+    if (iter != constraints.end()) {
+      return ((*iter).second).as<IntImm>()->value;
+    } else {
+      return def;
+    }
+  };
+
+  int64_t max_local_memory_per_block = get_int("max_local_memory_per_block", INT64_MAX);
+  int64_t max_shared_memory_per_block = get_int("max_shared_memory_per_block", INT64_MAX);
+  int64_t max_thread_per_block = get_int("max_thread_per_block", INT64_MAX);
+  int64_t max_thread_x = get_int("max_thread_x", INT64_MAX);
+  int64_t max_thread_y = get_int("max_thread_y", INT64_MAX);
+  int64_t max_thread_z = get_int("max_thread_z", INT64_MAX);
+
+  return verifier.Verify(stmt,
+                         max_local_memory_per_block,
+                         max_shared_memory_per_block,
+                         max_thread_per_block,
+                         max_thread_x,
+                         max_thread_y,
+                         max_thread_z);
+}
+
+}  // namespace ir
+}  // namespace tvm

src/runtime/cuda/cuda_device_api.cc

@@ -5,10 +5,12 @@
  */
 #include <tvm/runtime/device_api.h>
 
-#include <dmlc/logging.h>
 #include <dmlc/thread_local.h>
 #include <tvm/runtime/registry.h>
 #include <cuda_runtime.h>
+#include <tvm/container.h>
+#include <tvm/ir.h>
+#include <tvm/packed_func_ext.h>
 #include "./cuda_common.h"
 
 namespace tvm {
@@ -70,6 +72,20 @@ class CUDADeviceAPI final : public DeviceAPI {
             &value, cudaDevAttrMultiProcessorCount, ctx.device_id));
         break;
       }
+      case kMaxThreadDimensions: {
+        int dims[3];
+        CUDA_CALL(cudaDeviceGetAttribute(
+            &dims[0], cudaDevAttrMaxBlockDimX, ctx.device_id));
+        CUDA_CALL(cudaDeviceGetAttribute(
+            &dims[1], cudaDevAttrMaxBlockDimY, ctx.device_id));
+        CUDA_CALL(cudaDeviceGetAttribute(
+            &dims[2], cudaDevAttrMaxBlockDimZ, ctx.device_id));
+
+        std::stringstream ss;  // use json string to return multiple int values;
+        ss << "[" << dims[0] <<", " << dims[1] << ", " << dims[2] << "]";
+        *rv = ss.str();
+        return;
+      }
     }
     *rv = value;
   }

src/runtime/metal/metal_device_api.mm

@@ -42,6 +42,7 @@
     case kDeviceName: return;
     case kMaxClockRate: return;
     case kMultiProcessorCount: return;
+    case kMaxThreadDimensions: return;
     case kExist: break;
   }
 }

src/runtime/opencl/opencl_device_api.cc

@@ -4,6 +4,9 @@
  */
 #include <tvm/runtime/registry.h>
 #include <dmlc/thread_local.h>
+#include <tvm/container.h>
+#include <tvm/ir.h>
+#include <tvm/packed_func_ext.h>
 #include "./opencl_common.h"
 
 namespace tvm {
@@ -30,6 +33,7 @@ void OpenCLWorkspace::GetAttr(
   CHECK_LT(index, devices.size())
       << "Invalid device id " << index;
   switch (kind) {
+    case kExist: break;
     case kMaxThreadsPerBlock: {
       size_t value;
       OPENCL_CALL(clGetDeviceInfo(
@@ -80,7 +84,16 @@ void OpenCLWorkspace::GetAttr(
       *rv = static_cast<int32_t>(value);
       break;
     }
-    case kExist: break;
+    case kMaxThreadDimensions: {
+      size_t dims[3];
+      OPENCL_CALL(clGetDeviceInfo(
+          devices[index], CL_DEVICE_MAX_WORK_ITEM_SIZES, sizeof(dims), dims, nullptr));
+
+      std::stringstream ss;  // use json string to return multiple int values;
+      ss << "[" << dims[0] <<", " << dims[1] << ", " << dims[2] << "]";
+      *rv = ss.str();
+      break;
+    }
   }
 }
 

src/runtime/opengl/opengl_device_api.cc

@@ -97,6 +97,7 @@ void OpenGLWorkspace::GetAttr(
     case kDeviceName: return;
     case kMaxClockRate: return;
     case kMultiProcessorCount: return;
+    case kMaxThreadDimensions: return;
   }
 }
 

src/runtime/rocm/rocm_device_api.cc

@@ -52,6 +52,7 @@ class ROCMDeviceAPI final : public DeviceAPI {
       case kDeviceName: return;
       case kMaxClockRate: return;
       case kMultiProcessorCount: return;
+      case kMaxThreadDimensions: return;
     }
     *rv = value;
   }

src/runtime/vulkan/vulkan_device_api.cc

@@ -73,6 +73,7 @@ void VulkanWorkspace::GetAttr(
     case kMaxClockRate: return;
     case kMultiProcessorCount: return;
     case kExist: break;
+    case kMaxThreadDimensions: break;
   }
 }