From 92a02f580cfd28d7747e0401d5db1a379b426a26 Mon Sep 17 00:00:00 2001
From: Daniel Verkamp <daniel.verkamp@intel.com>
Date: Tue, 7 Jun 2016 11:31:12 -0700
Subject: [PATCH] build: generate config.h and implicitly include it

All source files will now depend on config.h, which is generated based
on the defaults in CONFIG and the command line arguments passed to make.

This ensures that any configuration changes, including on the command
line, cause a full rebuild.

Change-Id: I6b6fa3290941200dbcf32297c66df8dc5ee18e94
Signed-off-by: Daniel Verkamp <daniel.verkamp@intel.com>
---
 Makefile             | 10 +++++++++-
 mk/spdk.common.mk    |  2 ++
 scripts/genconfig.py | 33 +++++++++++++++++++++++++++++++++
 3 files changed, 44 insertions(+), 1 deletion(-)
 create mode 100755 scripts/genconfig.py

diff --git a/Makefile b/Makefile
index 47540c070..930ea5b72 100644
--- a/Makefile
+++ b/Makefile
@@ -38,13 +38,21 @@ include $(SPDK_ROOT_DIR)/mk/spdk.common.mk
 
 DIRS-y += lib test examples app
 
-.PHONY: all clean $(DIRS-y)
+.PHONY: all clean $(DIRS-y) config.h
 
 all: $(DIRS-y)
 clean: $(DIRS-y)
+	$(Q)rm -f config.h
 
 app: lib
 test: lib
 examples: lib
 
+$(DIRS-y): config.h
+
+config.h: CONFIG scripts/genconfig.py
+	$(Q)python scripts/genconfig.py $(MAKEFLAGS) > $@.tmp; \
+	cmp -s $@.tmp $@ || mv $@.tmp $@ ; \
+	rm -f $@.tmp
+
 include $(SPDK_ROOT_DIR)/mk/spdk.subdirs.mk
diff --git a/mk/spdk.common.mk b/mk/spdk.common.mk
index 6502cc68d..6f89b52f4 100644
--- a/mk/spdk.common.mk
+++ b/mk/spdk.common.mk
@@ -45,6 +45,8 @@ OS := $(shell uname)
 
 COMMON_CFLAGS = -g $(C_OPT) -Wall -Wextra -Wno-unused-parameter -Wno-missing-field-initializers -Wmissing-declarations -fno-strict-aliasing -march=native -m64 -I$(SPDK_ROOT_DIR)/include
 
+COMMON_CFLAGS += -include $(SPDK_ROOT_DIR)/config.h
+
 ifeq ($(CONFIG_WERROR), y)
 COMMON_CFLAGS += -Werror
 endif
diff --git a/scripts/genconfig.py b/scripts/genconfig.py
new file mode 100755
index 000000000..64f1ce52d
--- /dev/null
+++ b/scripts/genconfig.py
@@ -0,0 +1,33 @@
+#!/usr/bin/env python
+
+import re
+import sys
+
+comment = re.compile('^\s*#')
+assign = re.compile('^\s*([a-zA-Z_]+)\s*(\?)?=\s*([^#]*)')
+
+with open('CONFIG') as f:
+    for line in f:
+        line = line.strip()
+        if not comment.match(line):
+            m = assign.match(line)
+            if m:
+                var = m.group(1).strip()
+                default = m.group(3).strip()
+                val = default
+                for arg in sys.argv:
+                    m = assign.match(arg)
+                    if m:
+                        argvar = m.group(1).strip()
+                        argval = m.group(3).strip()
+                        if argvar == var:
+                            val = argval
+                if default.lower() == 'y' or default.lower() == 'n':
+                    if val.lower() == 'y':
+                        boolval = 1
+                    else:
+                        boolval = 0
+                    print "#define SPDK_{} {}".format(var, boolval)
+                else:
+                    strval = val.replace('"', '\"')
+                    print "#define SPDK_{} \"{}\"".format(var, strval)