Build ORCA with C++14: Take Two (#10068)

This patch makes the minimal changes to build ORCA with C++14. This
should address the grievance that ORCA cannot build with the default
Xerces C++ (3.2 or newer, which is built with GCC 8.3 in the default
C++14 mode) headers from Debian. I've kept the CMake build system in
sync with the main Makefile. I've also made sure that all ORCA tests
pass.

This patch set also enables ORCA in Travis so the community gets
compilation coverage.

=== FIXME / near-term TODOs:

What's _not_ included in this patch, but would be nice to have soon (in
descending order of importance):

1. -std=gnu++14 ought to be done in "configure", not in a Makefile. This
is not a pendantic aesthetic issue, sooner or later we'll run into this
problem, especially if we're mixing multiple things built in C++.

2. Clean up the Makefiles and move most CXXFLAGS override into autoconf.

3. Those noexept(false) seem excessive, we should benefit from
conditionally marking more code "noexcept" at least in production.

4. Detecting whether Xerces was generated (either by autoconf or CMake)
with a compiler that's effectively running post-C++11

5. Work around a GCC 9.2 bug that crashes the loading of minidumps (I've
tested with GCC 6 to 10). Last I checked, the bug has been fixed in GCC
releases 10.1 and 9.3.

[resolves #9923]
[resolves #10047]
Co-authored-by: NMelanie Plageman <mplageman@pivotal.io>
Reviewed-by: NHans Zeller <hzeller@pivotal.io>
Reviewed-by: NAshuka Xue <axue@pivotal.io>
Reviewed-by: NDavid Kimura <dkimura@pivotal.io>

.travis.yml

@@ -18,6 +18,7 @@ addons:
             - gcc-8
             - libxml2
             - libxml2-dev
+            - libxerces-c-dev
             - libevent-dev
             - libperl-dev
             - g++-8
@@ -69,6 +70,7 @@ matrix:
             homebrew:
               packages:
                 - ccache
+                - xerces-c
         #
         # Configuration variations
         # ----------------------------------------------------------------
@@ -146,7 +148,7 @@ script:
             --enable-debug-extensions \
             --with-perl \
             --with-python \
-            --disable-orca \
+            --enable-orca \
             --with-openssl \
             --with-ldap \
             --with-libcurl \
@@ -154,7 +156,7 @@ script:
             --enable-mapreduce \
             --enable-orafce \
             $C
-        make -s install
+        travis_wait 40 make -s install
         source ${TRAVIS_BUILD_DIR}/gpsql/greenplum_path.sh
         make -s unittest-check
         make -C gpAux/gpdemo cluster
@@ -168,7 +170,7 @@ script:
             --prefix=${TRAVIS_BUILD_DIR}/gpsql \
             --with-perl \
             --with-python \
-            --disable-orca \
+            --enable-orca \
             --with-openssl \
             --with-ldap \
             --with-libcurl \
@@ -196,6 +198,8 @@ script:
             --disable-pxf \
             --disable-gpcloud \
             --without-zstd \
+            --with-includes=$(brew --prefix xerces-c)/include \
+            --with-libs=$(brew --prefix xerces-c)/lib \
             $C
         make -s install
         source ${TRAVIS_BUILD_DIR}/gpsql/greenplum_path.sh

src/backend/gporca/CMakeLists.txt

@@ -3,7 +3,7 @@
 cmake_minimum_required(VERSION 3.1 FATAL_ERROR)
 project(gpopt_master LANGUAGES CXX C)
 
-set(CMAKE_CXX_STANDARD 98)
+set(CMAKE_CXX_STANDARD 14)
 
 # Default to shared libraries.
 option(BUILD_SHARED_LIBS "build shared libraries" ON)

src/backend/gporca/gporca.mk

@@ -6,4 +6,4 @@ override CPPFLAGS := -I$(top_srcdir)/src/backend/gporca/libgpdbcost/include $(CP
 # backtracing.
 override CXXFLAGS := -Werror -Wextra -Wpedantic -Wno-variadic-macros -fno-omit-frame-pointer $(CXXFLAGS)
 # FIXME: this really should be done in autoconf
-override CXXFLAGS := -std=gnu++98 $(CXXFLAGS)
+override CXXFLAGS := -std=gnu++14 $(CXXFLAGS)

src/backend/gporca/libgpopt/include/gpopt/xforms/CJoinOrderDPv2.h

@@ -331,8 +331,7 @@ namespace gpopt
 
 				SGroupAndExpression() : m_group_info(NULL), m_expr_index(gpos::ulong_max) {}
 				SGroupAndExpression(SGroupInfo *g, ULONG ix) : m_group_info(g), m_expr_index(ix) {}
-				SGroupAndExpression(const SGroupAndExpression &other) : m_group_info(other.m_group_info),
-																		  m_expr_index(other.m_expr_index) {}
+				SGroupAndExpression(const SGroupAndExpression &other) = default;
 				SExpressionInfo *GetExprInfo() const { return (*m_group_info->m_best_expr_info_array)[m_expr_index]; }
 				BOOL IsValid() { return NULL != m_group_info && gpos::ulong_max != m_expr_index; }
 				BOOL operator == (const SGroupAndExpression &other) const

src/backend/gporca/libgpos/include/gpos/common/CAutoP.h

@@ -39,15 +39,14 @@ namespace gpos
 
 			// actual element to point to
 			T *m_object;
-						
-			// hidden copy ctor
+
+		public:
+
 			CAutoP<T>
 				(
 				const CAutoP&
-				);
+				) = delete;
 
-		public:
-		
 			// ctor
 			explicit
 			CAutoP<T>()

src/backend/gporca/libgpos/include/gpos/common/CAutoRg.h

@@ -35,12 +35,11 @@ namespace gpos
 
 			// actual element to point to
 			T *m_object_array;
-						
-			// hidden copy ctor
-			CAutoRg<T>(const CAutoRg&);
 
 		public:
-		
+
+			CAutoRg<T>(const CAutoRg&) = delete;
+
 			// ctor
 			explicit
 			CAutoRg<T>()

src/backend/gporca/libgpos/include/gpos/common/CDouble.h

@@ -111,14 +111,6 @@ namespace gpos
 				return m_d;
 			}
 
-			// assignment
-			inline CDouble& operator=(const CDouble &right)
-            {
-                this->m_d = right.m_d;
-
-                return (*this);
-            }
-
 			// arithmetic operators
 			friend CDouble operator + (const CDouble &left, const CDouble &right)
             {

src/backend/gporca/libgpos/include/gpos/common/CLink.h

@@ -19,8 +19,7 @@ namespace gpos
 
 		private:
 
-			// no copy constructor
-			SLink(const SLink&);
+			SLink(const SLink&) = delete;
 
 		public:
 

src/backend/gporca/libgpos/include/gpos/common/CRefCount.h

@@ -63,8 +63,9 @@ namespace gpos
 				m_refs(1)
 			{}
 
+			// FIXME: should mark this noexcept in non-assert builds
 			// dtor
-			virtual ~CRefCount()
+			virtual ~CRefCount() noexcept(false)
 			{
 				// enforce strict ref-counting unless we're in a pending exception,
 				// e.g., a ctor has thrown

src/backend/gporca/libgpos/include/gpos/memory/CAutoMemoryPool.h

@@ -68,8 +68,9 @@ namespace gpos
 				ELeakCheck leak_check_type = ElcExc
 				);
 
+			// FIXME: should mark this noexcept in non-assert builds
 			// dtor
-			~CAutoMemoryPool();
+			~CAutoMemoryPool() noexcept(false);
 
 			// accessor
 			CMemoryPool *Pmp() const

src/backend/gporca/libgpos/server/include/unittest/gpos/common/CSyncHashtableTest.h

@@ -160,6 +160,8 @@ namespace gpos
 						m_ulKey = elem.m_ulKey;
 					}
 
+					SElem& operator = (const SElem&) = default;
+
 #ifdef GPOS_DEBUG
 					static
 					BOOL IsValid

src/backend/gporca/libgpos/src/memory/CAutoMemoryPool.cpp

@@ -79,7 +79,7 @@ CAutoMemoryPool::Detach()
 //		(2) no checking while pending exception indicated and no pending exception
 //
 //---------------------------------------------------------------------------
-CAutoMemoryPool::~CAutoMemoryPool()
+CAutoMemoryPool::~CAutoMemoryPool() noexcept(false)
 {
 	if (NULL == m_mp)
 	{

src/backend/gporca/server/src/unittest/dxl/CParseHandlerCostModelTest.cpp

@@ -45,7 +45,7 @@ namespace
 		private:
 			CAutoMemoryPool m_amp;
 			gpos::CAutoP<CDXLMemoryManager> m_apmm;
-			std::auto_ptr<SAX2XMLReader> m_apxmlreader;
+			std::unique_ptr<SAX2XMLReader> m_apxmlreader;
 			gpos::CAutoP<CParseHandlerManager> m_apphm;
 			gpos::CAutoP<CParseHandlerCostModel> m_apphCostModel;