diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -12950,7 +12950,8 @@
     //   expression or statement in the body of the function [and thus before
     //   the value computation of its result].
     SequencedSubexpression Sequenced(*this);
-    Base::VisitCallExpr(CE);
+    SemaRef.runWithSufficientStackSpace(CE->getExprLoc(),
+                                        [&] { Base::VisitCallExpr(CE); });
 
     // FIXME: CXXNewExpr and CXXDeleteExpr implicitly call functions.
   }
diff --git a/clang/tools/libclang/CIndex.cpp b/clang/tools/libclang/CIndex.cpp
--- a/clang/tools/libclang/CIndex.cpp
+++ b/clang/tools/libclang/CIndex.cpp
@@ -3595,6 +3595,7 @@
     const char *const *command_line_args, int num_command_line_args,
     struct CXUnsavedFile *unsaved_files, unsigned num_unsaved_files,
     unsigned options, CXTranslationUnit *out_TU) {
+  noteBottomOfStack();
   SmallVector<const char *, 4> Args;
   Args.push_back("clang");
   Args.append(command_line_args, command_line_args + num_command_line_args);
@@ -3619,6 +3620,7 @@
 
   CXErrorCode result = CXError_Failure;
   auto ParseTranslationUnitImpl = [=, &result] {
+    noteBottomOfStack();
     result = clang_parseTranslationUnit_Impl(
         CIdx, source_filename, command_line_args, num_command_line_args,
         llvm::makeArrayRef(unsaved_files, num_unsaved_files), options, out_TU);
@@ -6622,9 +6624,10 @@
 
 void clang_executeOnThread(void (*fn)(void*), void *user_data,
                            unsigned stack_size) {
-  llvm::llvm_execute_on_thread(
-      fn, user_data,
-      stack_size == 0 ? llvm::None : llvm::Optional<unsigned>(stack_size));
+  llvm::llvm_execute_on_thread(fn, user_data,
+                               stack_size == 0
+                                   ? clang::DesiredStackSize
+                                   : llvm::Optional<unsigned>(stack_size));
 }
 
 //===----------------------------------------------------------------------===//