big cpp test reorg (#24801)

Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/24801

This is to fix the ODR-violations in fbcode static builds, which have been broken for several months.

This PR is unfortunately quite large, but the changes are only mechanical:
1. Tests defined in header files -> tests defined in cpp files
2. Remove the `torch::jit::testing` namespace -> `torch::jit`.
3. Single `test.h` file that aggregates all tests.
4. Separate out files for gtest and python versions of the tests instead of using a build flag
5. Add a readme for how to add a new test, and explaining a bit about why the cpp tests are the way they are.

Test Plan: Imported from OSS

Differential Revision: D16878605

Pulled By: suo

fbshipit-source-id: 27b5c077dadd990a5f74e25d01731f9c1f491603

test/cpp/jit/test_constant_pooling.cpp

@@ -0,0 +1,103 @@
+#include <torch/csrc/jit/ir.h>
+#include <torch/csrc/jit/irparser.h>
+#include <torch/csrc/jit/passes/constant_pooling.h>
+#include <torch/csrc/jit/passes/constant_propagation.h>
+#include <torch/csrc/jit/testing/file_check.h>
+#include "test/cpp/jit/test_base.h"
+
+#include <sstream>
+#include <string>
+
+namespace torch {
+namespace jit {
+
+void testConstantPooling() {
+  {
+    auto graph = std::make_shared<Graph>();
+    script::parseIR(
+        R"IR(
+graph():
+  %8 : int = prim::Constant[value=1]()
+  %10 : int = prim::Constant[value=1]()
+  return (%8, %10)
+  )IR",
+        &*graph);
+    ConstantPooling(graph);
+    testing::FileCheck()
+        .check_count("prim::Constant", 1, /*exactly*/ true)
+        ->run(*graph);
+  }
+  {
+    auto graph = std::make_shared<Graph>();
+    script::parseIR(
+        R"IR(
+graph(%cond : Tensor):
+  %a : str = prim::Constant[value="bcd"]()
+  %3 : bool = aten::Bool(%cond)
+  %b : str = prim::If(%3)
+    block0():
+      %b.1 : str = prim::Constant[value="abc"]()
+      -> (%b.1)
+    block1():
+      %b.2 : str = prim::Constant[value="abc"]()
+      -> (%b.2)
+  %7 : (str, str) = prim::TupleConstruct(%a, %b)
+  return (%7)
+  )IR",
+        &*graph);
+    ConstantPooling(graph);
+    testing::FileCheck()
+        .check_count("prim::Constant[value=\"abc\"]", 1, /*exactly*/ true)
+        ->check_count("prim::Constant[value=\"bcd\"]", 1, /*exactly*/ true)
+        ->run(*graph);
+  }
+  {
+    auto graph = std::make_shared<Graph>();
+    script::parseIR(
+        R"IR(
+graph():
+  %2 : int = prim::Constant[value=2]()
+  %1 : int = prim::Constant[value=1]()
+  %5 : int? = prim::Constant()
+  %7 : Device? = prim::Constant()
+  %15: bool = prim::Constant[value=0]()
+  %10 : int = prim::Constant[value=6]()
+  %3 : int[] = prim::ListConstruct(%1, %2)
+  %x : Tensor = aten::tensor(%3, %5, %7, %15)
+  %y : Tensor = aten::tensor(%3, %10, %7, %15)
+  %9 : int[] = prim::ListConstruct(%1, %2)
+  %z : Tensor = aten::tensor(%9, %10, %7, %15)
+  %f = prim::Print(%x, %y, %z)
+  return (%1)
+  )IR",
+        &*graph);
+    // three tensors created - two different devices among the three
+    // don't have good support for parsing tensor constants
+    ConstantPropagation(graph);
+    ConstantPooling(graph);
+    testing::FileCheck()
+        .check_count("Float(2) = prim::Constant", 1, /*exactly*/ true)
+        ->check_count("Long(2) = prim::Constant", 1, /*exactly*/ true)
+        ->run(*graph);
+  }
+  // don't create aliasing of graph outputs in constant pooling
+  {
+    auto graph = std::make_shared<Graph>();
+    script::parseIR(
+        R"IR(
+graph(%cond : Tensor):
+  %a : Tensor = prim::Constant()
+  %b : Tensor = prim::Constant()
+  %c : Tensor = prim::Constant()
+  %1 = prim::Print(%c)
+  return (%a, %b)
+  )IR",
+        &*graph);
+    ConstantPooling(graph);
+    testing::FileCheck()
+        .check_count("prim::Constant", 2, /*exactly*/ true)
+        ->run(*graph);
+  }
+}
+} // namespace jit
+} // namespace torch