Removing instances of exec_ctx being passed around in functions in

src/core. exec_ctx is now a thread_local pointer of type ExecCtx instead of
grpc_exec_ctx which is initialized whenever ExecCtx is instantiated. ExecCtx
also keeps track of the previous exec_ctx so that nesting of exec_ctx is
allowed. This means that there is only one exec_ctx being used at any
time. Also, grpc_exec_ctx_finish is called in the destructor of the
object, and the previous exec_ctx is restored to avoid breaking current
functionality. The code still explicitly calls grpc_exec_ctx_finish
because removing all such instances causes the code to break.

3 files changed, 16 insertions, 17 deletions

diff --git a/test/cpp/end2end/client_lb_end2end_test.cc b/test/cpp/end2end/client_lb_end2end_test.cc
index c236f76e89..d129a961ba 100644
--- a/test/cpp/end2end/client_lb_end2end_test.cc
+++ b/test/cpp/end2end/client_lb_end2end_test.cc
@@ -109,12 +109,12 @@ class ClientLbEnd2endTest : public ::testing::Test {
   }
 
   void SetNextResolution(const std::vector<int>& ports) {
-    grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
+    ExecCtx _local_exec_ctx;
     grpc_lb_addresses* addresses = grpc_lb_addresses_create(ports.size(), NULL);
     for (size_t i = 0; i < ports.size(); ++i) {
       char* lb_uri_str;
       gpr_asprintf(&lb_uri_str, "ipv4:127.0.0.1:%d", ports[i]);
-      grpc_uri* lb_uri = grpc_uri_parse(&exec_ctx, lb_uri_str, true);
+      grpc_uri* lb_uri = grpc_uri_parse(lb_uri_str, true);
       GPR_ASSERT(lb_uri != NULL);
       grpc_lb_addresses_set_address_from_uri(addresses, i, lb_uri,
                                              false /* is balancer */,
@@ -126,11 +126,11 @@ class ClientLbEnd2endTest : public ::testing::Test {
         grpc_lb_addresses_create_channel_arg(addresses);
     grpc_channel_args* fake_result =
         grpc_channel_args_copy_and_add(NULL, &fake_addresses, 1);
-    grpc_fake_resolver_response_generator_set_response(
-        &exec_ctx, response_generator_, fake_result);
-    grpc_channel_args_destroy(&exec_ctx, fake_result);
-    grpc_lb_addresses_destroy(&exec_ctx, addresses);
-    grpc_exec_ctx_finish(&exec_ctx);
+    grpc_fake_resolver_response_generator_set_response(response_generator_,
+                                                       fake_result);
+    grpc_channel_args_destroy(fake_result);
+    grpc_lb_addresses_destroy(addresses);
+    grpc_exec_ctx_finish();
   }
 
   void ResetStub(const grpc::string& lb_policy_name = "") {
diff --git a/test/cpp/end2end/filter_end2end_test.cc b/test/cpp/end2end/filter_end2end_test.cc
index f260ea0016..c4430379db 100644
--- a/test/cpp/end2end/filter_end2end_test.cc
+++ b/test/cpp/end2end/filter_end2end_test.cc
@@ -100,7 +100,7 @@ int GetCallCounterValue() {
 
 class ChannelDataImpl : public ChannelData {
  public:
-  grpc_error* Init(grpc_exec_ctx* exec_ctx, grpc_channel_element* elem,
+  grpc_error* Init(grpc_channel_element* elem,
                    grpc_channel_element_args* args) {
     IncrementConnectionCounter();
     return GRPC_ERROR_NONE;
@@ -109,13 +109,12 @@ class ChannelDataImpl : public ChannelData {
 
 class CallDataImpl : public CallData {
  public:
-  void StartTransportStreamOpBatch(grpc_exec_ctx* exec_ctx,
-                                   grpc_call_element* elem,
+  void StartTransportStreamOpBatch(grpc_call_element* elem,
                                    TransportStreamOpBatch* op) override {
     // Incrementing the counter could be done from Init(), but we want
     // to test that the individual methods are actually called correctly.
     if (op->recv_initial_metadata() != nullptr) IncrementCallCounter();
-    grpc_call_next_op(exec_ctx, elem, op->op());
+    grpc_call_next_op(elem, op->op());
   }
 };
 
diff --git a/test/cpp/end2end/grpclb_end2end_test.cc b/test/cpp/end2end/grpclb_end2end_test.cc
index f73a9c1791..1157c4510e 100644
--- a/test/cpp/end2end/grpclb_end2end_test.cc
+++ b/test/cpp/end2end/grpclb_end2end_test.cc
@@ -449,13 +449,13 @@ class GrpclbEnd2endTest : public ::testing::Test {
   };
 
   void SetNextResolution(const std::vector<AddressData>& address_data) {
-    grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
+    ExecCtx _local_exec_ctx;
     grpc_lb_addresses* addresses =
         grpc_lb_addresses_create(address_data.size(), nullptr);
     for (size_t i = 0; i < address_data.size(); ++i) {
       char* lb_uri_str;
       gpr_asprintf(&lb_uri_str, "ipv4:127.0.0.1:%d", address_data[i].port);
-      grpc_uri* lb_uri = grpc_uri_parse(&exec_ctx, lb_uri_str, true);
+      grpc_uri* lb_uri = grpc_uri_parse(lb_uri_str, true);
       GPR_ASSERT(lb_uri != nullptr);
       grpc_lb_addresses_set_address_from_uri(
           addresses, i, lb_uri, address_data[i].is_balancer,
@@ -465,10 +465,10 @@ class GrpclbEnd2endTest : public ::testing::Test {
     }
     grpc_arg fake_addresses = grpc_lb_addresses_create_channel_arg(addresses);
     grpc_channel_args fake_result = {1, &fake_addresses};
-    grpc_fake_resolver_response_generator_set_response(
-        &exec_ctx, response_generator_, &fake_result);
-    grpc_lb_addresses_destroy(&exec_ctx, addresses);
-    grpc_exec_ctx_finish(&exec_ctx);
+    grpc_fake_resolver_response_generator_set_response(response_generator_,
+                                                       &fake_result);
+    grpc_lb_addresses_destroy(addresses);
+    grpc_exec_ctx_finish();
   }
 
   const std::vector<int> GetBackendPorts(const size_t start_index = 0) const {