From 2373c99433b634b8cf9c4deb28d68d1be255a564 Mon Sep 17 00:00:00 2001
From: Mikhail Glushenkov <foldr@codedgers.com>
Date: Fri, 3 Jul 2009 03:52:47 +0000
Subject: [PATCH] Add --enable-llvmc-dynamic configure option.

Controls whether libCompilerDriver should be loaded dynamically. By default this
is needed only on Win32, to make dynamic plugins work.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@74759 91177308-0d34-0410-b5e6-96231b3b80d8
---
 Makefile.config.in          |  6 ++++++
 Makefile.rules              | 21 +++++++++++++++------
 autoconf/configure.ac       | 18 ++++++++++++++++++
 lib/CompilerDriver/Makefile | 17 +++++++++++++----
 4 files changed, 52 insertions(+), 10 deletions(-)

diff --git a/Makefile.config.in b/Makefile.config.in
index 44d7416e4f8..e7159028146 100644
--- a/Makefile.config.in
+++ b/Makefile.config.in
@@ -297,3 +297,9 @@ endif
 
 # Location of the plugin header file for gold.
 BINUTILS_INCDIR := @BINUTILS_INCDIR@
+
+# When ENABLE_LLVMC_DYNAMIC is enabled, LLVMC will link libCompilerDriver
+# dynamically. This is needed to make dynamic plugins work on some targets
+# (Windows).
+ENABLE_LLVMC_DYNAMIC = 0
+#@ENABLE_LLVMC_DYNAMIC@
diff --git a/Makefile.rules b/Makefile.rules
index 9787d5fe0b5..3ae2db8916d 100644
--- a/Makefile.rules
+++ b/Makefile.rules
@@ -200,17 +200,20 @@ ifdef LLVMC_PLUGIN
 LIBRARYNAME := $(patsubst %,plugin_llvmc_%,$(LLVMC_PLUGIN))
 CPP.Flags += -DLLVMC_PLUGIN_NAME=$(LLVMC_PLUGIN)
 REQUIRES_EH := 1
-LD.Flags += -lCompilerDriver
+
+ifeq ($(ENABLE_LLVMC_DYNAMIC),1)
+  LD.Flags += -lCompilerDriver
+endif
 
 # Build a dynamic library if the user runs `make` directly from the plugin
 # directory.
 ifndef LLVMC_BUILTIN_PLUGIN
-LOADABLE_MODULE = 1
+  LOADABLE_MODULE = 1
 endif
 
 # TableGen stuff...
 ifneq ($(BUILT_SOURCES),)
-LLVMC_BUILD_AUTOGENERATED_INC=1
+  LLVMC_BUILD_AUTOGENERATED_INC=1
 endif
 
 endif # LLVMC_PLUGIN
@@ -218,8 +221,15 @@ endif # LLVMC_PLUGIN
 ifdef LLVMC_BASED_DRIVER
 
 TOOLNAME = $(LLVMC_BASED_DRIVER)
+
 REQUIRES_EH := 1
-LD.Flags += -lCompilerDriver
+
+ifeq ($(ENABLE_LLVMC_DYNAMIC),1)
+  LD.Flags += -lCompilerDriver
+else
+  LLVMLIBS = CompilerDriver.a
+  LINK_COMPONENTS = support system
+endif
 
 # Preprocessor magic that generates references to static variables in built-in
 # plugins.
@@ -502,8 +512,7 @@ ifeq ($(OS),Darwin)
 else
   ifeq ($(OS),Cygwin)
     SharedLinkOptions=-shared -nostdlib -Wl,--export-all-symbols \
-                      -Wl,--enable-auto-import -Wl,--enable-auto-image-base \
-                      -Wl,--enable-runtime-pseudo-relocs
+                      -Wl,--enable-auto-import -Wl,--enable-auto-image-base
   else
     SharedLinkOptions=-shared
   endif
diff --git a/autoconf/configure.ac b/autoconf/configure.ac
index 0ed3a26f6c2..bb9c9d84b00 100644
--- a/autoconf/configure.ac
+++ b/autoconf/configure.ac
@@ -593,6 +593,24 @@ case "$enableval" in
   *) AC_MSG_ERROR([Invalid setting for --enable-libffi. Use "yes" or "no"]) ;;
 esac
 
+dnl Only Windows needs dynamic libCompilerDriver to support plugins.
+if test "$llvm_cv_os_type" = "Win32" ; then
+   llvmc_dynamic="yes"
+else
+   llvmc_dynamic="no"
+fi
+
+dnl --enable-llvmc-dynamic : should LLVMC link libCompilerDriver dynamically?
+AC_ARG_ENABLE(llvmc-dynamic,AS_HELP_STRING(
+--enable-llvmc-dynamic,
+[Link LLVMC dynamically (default is NO, unless on Win32)]),,
+enableval=$llvmc_dynamic)
+if test ${enableval} = "no"; then
+   AC_SUBST(ENABLE_LLVMC_DYNAMIC,[[]])
+else
+   AC_SUBST(ENABLE_LLVMC_DYNAMIC,[[ENABLE_LLVMC_DYNAMIC=1]])
+fi
+
 dnl===-----------------------------------------------------------------------===
 dnl===
 dnl=== SECTION 4: Check for programs we need and that they are the right version
diff --git a/lib/CompilerDriver/Makefile b/lib/CompilerDriver/Makefile
index 773eb5e8e1a..6084e885184 100644
--- a/lib/CompilerDriver/Makefile
+++ b/lib/CompilerDriver/Makefile
@@ -12,18 +12,26 @@ LEVEL = ../..
 # We don't want this library to appear in `llvm-config --libs` output, so its
 # name doesn't start with "LLVM".
 
-LIBRARYNAME = libCompilerDriver
-LLVMLIBS = LLVMSupport.a LLVMSystem.a
-LOADABLE_MODULE := 1
+ifeq ($(ENABLE_LLVMC_DYNAMIC),1)
+  LIBRARYNAME = libCompilerDriver
+  LLVMLIBS = LLVMSupport.a LLVMSystem.a
+  LOADABLE_MODULE := 1
+else
+  LIBRARYNAME = CompilerDriver
+  LINK_COMPONENTS = support system
+endif
+
 REQUIRES_EH := 1
 
 include $(LEVEL)/Makefile.common
 
+# Copy libCompilerDriver to the bin dir so that llvmc can find it.
+ifeq ($(ENABLE_LLVMC_DYNAMIC),1)
+
 FullLibName = $(LIBRARYNAME)$(SHLIBEXT)
 
 all-local:: $(ToolDir)/$(FullLibName)
 
-# Copy the library to the bin dir so that llvmc can find it.
 $(ToolDir)/$(FullLibName): $(LibDir)/$(FullLibName) $(ToolDir)/.dir
 	$(Echo) Copying $(BuildMode) Shared Library $(FullLibName) to $@
 	-$(Verb) $(CP) $< $@
@@ -32,3 +40,4 @@ clean-local::
 	$(Echo) Removing $(BuildMode) Shared Library $(FullLibName) \
 	from $(ToolDir)
 	-$(Verb) $(RM) -f $(ToolDir)/$(FullLibName)
+endif
-- 
2.34.1