From c933d77963b7233dc98a577c85e95f4d32f5c2dc Mon Sep 17 00:00:00 2001
From: Andrew Johnson <anj@aps.anl.gov>
Date: Tue, 26 Apr 2016 15:18:31 -0500
Subject: [PATCH] Add rule to install libraries before linking executables

The rule must be disabled for building libCom and gdd though.
---
 configure/RULES_BUILD            |  8 +++++++-
 documentation/RELEASE_NOTES.html | 12 ++++++++++++
 src/ca/legacy/gdd/Makefile       |  5 +++++
 src/libCom/Makefile              |  5 +++++
 4 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/configure/RULES_BUILD b/configure/RULES_BUILD
index 37e54372f..026246ee6 100644
--- a/configure/RULES_BUILD
+++ b/configure/RULES_BUILD
@@ -170,7 +170,13 @@ endif
 $(DIRECTORY_TARGETS) :
 	$(MKDIR) -p $@
 
-$(PRODNAME): $(INSTALL_LIB_INSTALLS)
+# Install LIB_INSTALLS libraries before linking executables
+$(TESTPRODNAME) $(PRODNAME): | $(INSTALL_LIB_INSTALLS)
+
+# Install built libraries too, unless Makefile says to wait
+ifneq ($(DELAY_INSTALL_LIBS),YES)
+$(TESTPRODNAME) $(PRODNAME): | $(INSTALL_LIBS) $(INSTALL_DLLSTUB_LIBS)
+endif
 
 # RELEASE file consistency checking
 checkRelease:
diff --git a/documentation/RELEASE_NOTES.html b/documentation/RELEASE_NOTES.html
index fc46ff8cb..05a9da078 100644
--- a/documentation/RELEASE_NOTES.html
+++ b/documentation/RELEASE_NOTES.html
@@ -15,6 +15,18 @@
 <h2 align="center">Changes made on the 3.15 branch since 3.15.3</h2>
 <!-- Insert new items immediately below here ... -->
 
+<h3>Build rules and DELAY_INSTALL_LIBS</h3>
+
+<p>A new order-only prerequisite build rule has been added to ensure that
+library files (and DLL stubs on Windows) get installed before linking any
+executables, which resolves parallel build problems on high-powered CPUs. There
+are some (rare) cases though where a Makefile has to build an executable and run
+it to be able to compile code for a library built by the same Makefile. With
+this new build rule GNUmake will complain about a circular dependency and the
+build will probably fail in those cases. To avoid this problem the failing
+Makefile should set <tt>DELAY_INSTALL_LIBS = YES</tt> before including the
+<tt>$(TOP)/configure/RULES</tt> file, disabling the new build rule.</p>
+
 <h3>CA server configuration changes</h3>
 
 <p>RSRV now honors EPICS_CAS_INTF_ADDR_LIST and binds only to the provided list
diff --git a/src/ca/legacy/gdd/Makefile b/src/ca/legacy/gdd/Makefile
index b1e8fceaa..9c5638eb4 100644
--- a/src/ca/legacy/gdd/Makefile
+++ b/src/ca/legacy/gdd/Makefile
@@ -69,6 +69,11 @@ CLEANS += $(COMMON_DIR)/aitConvertGenerated.cc
 USR_CXXFLAGS_Linux = -fno-strict-aliasing
 USR_CXXFLAGS_RTEMS = -fno-strict-aliasing
 
+ifeq ($(T_A),$(EPICS_HOST_ARCH))
+  # genApps and aitGen are needed to finish libgdd
+  DELAY_INSTALL_LIBS = YES
+endif
+
 include $(TOP)/configure/RULES
 
 # Manual dependencies
diff --git a/src/libCom/Makefile b/src/libCom/Makefile
index 767180316..33955acfd 100644
--- a/src/libCom/Makefile
+++ b/src/libCom/Makefile
@@ -45,6 +45,11 @@ Com_SYS_LIBS_WIN32 = ws2_32 advapi32 user32
 
 Com_RCS = Com.rc
 
+ifeq ($(T_A),$(EPICS_HOST_ARCH))
+  # Antelope & flex are needed to finish libCom
+  DELAY_INSTALL_LIBS = YES
+endif
+
 include $(TOP)/configure/RULES
 
 include $(LIBCOM)/as/RULES