[libc] Allow assertions to be globally enabled or disabled

Assertions are enabled for objects built with any debug level
(including an explicit debug level of zero).  It is sometimes useful
to be able to enable assertions across all objects; this currently
requires manually hacking include/assert.h.

Allow assertions to be globally enabled by adding ASSERT=1 to the
build command line.  For example:

  make bin/8086100e.mrom ASSERT=1

Similarly, allow assertions to be globally disabled by adding ASSERT=0
to the build command line.  If no ASSERT=... is specified on the
build command line, then only objects mentioned in DEBUG=... will have
assertions enabled (as is currently the case).

Note than globally enabling assertions imposes a relatively heavy
runtime penalty, primarily due to the various sanity checks performed
by list_add(), list_for_each_entry(), etc.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

diff --git a/src/Makefile.housekeeping b/src/Makefile.housekeeping
index 264b9d0f949020fda568119caf72b7babc00685e..a02acc8ddcdaf7ebc439b50b0ab6410c9c55d289 100644 (file)
--- a/src/Makefile.housekeeping
+++ b/src/Makefile.housekeeping
@@ -720,6 +720,33 @@ config/named.h : $(CONFIG_LIST)
 
 .PRECIOUS : config/named.h
 
+# (Single-element) list of assertion configuration
+#
+ASSERT_LIST := $(BIN)/.assert.list
+ifeq ($(wildcard $(ASSERT_LIST)),)
+ASSERT_OLD := <invalid>
+else
+ASSERT_OLD := $(shell cat $(ASSERT_LIST))
+endif
+ifneq ($(ASSERT_OLD),$(ASSERT))
+$(shell $(ECHO) "$(ASSERT)" > $(ASSERT_LIST))
+endif
+
+$(ASSERT_LIST) : $(MAKEDEPS)
+
+VERYCLEANUP += $(ASSERT_LIST)
+
+# Assertion configuration
+#
+ifneq ($(ASSERT),)
+CFLAGS += -DASSERTING=$(ASSERT)
+endif
+
+include/assert.h : $(ASSERT_LIST)
+       $(Q)$(TOUCH) $@
+
+.PRECIOUS : include/assert.h
+
 # These files use .incbin inline assembly to include a binary file.
 # Unfortunately ccache does not detect this dependency and caches
 # builds even when the binary file has changed.

diff --git a/src/include/assert.h b/src/include/assert.h
index 07f3ecb8c96f68721141963dbc7094febc90da4d..dd71fa7137c3fbbb5139424b82b4d52c04e54b31 100644 (file)
--- a/src/include/assert.h
+++ b/src/include/assert.h
@@ -12,11 +12,13 @@
 
 FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
 
+#ifndef ASSERTING
 #ifdef NDEBUG
 #define ASSERTING 0
 #else
 #define ASSERTING 1
 #endif
+#endif
 
 extern unsigned int assertion_failures;