From dffb03a562e633aad87f2722ab8c2cfde671ab92 Mon Sep 17 00:00:00 2001
From: Jason Volk <jason@zemos.net>
Date: Sun, 11 Aug 2019 19:02:50 -0700
Subject: [PATCH] ircd: Cleanup / simplify assert related interface.

---
 configure.ac          |  4 +++
 include/ircd/assert.h | 58 ++++++++++++++++++++++++++++---------------
 ircd/assert.cc        | 49 ++++++++++++++----------------------
 3 files changed, 61 insertions(+), 50 deletions(-)

diff --git a/configure.ac b/configure.ac
index 6a804fb79..465e1143d 100644
--- a/configure.ac
+++ b/configure.ac
@@ -227,6 +227,10 @@ AM_COND_IF(ASSERT,
 	if [[ ! -z "$assert_type" ]]; then
 		RB_DEFINE_UNQUOTED([ASSERT], ["$assert_type"], [Assertion behavior])
 	fi
+
+	if [ "$assert_type" == "trap" ]; then
+		RB_DEFINE([ASSERT_INTRINSIC], [1], [Intrinsic assertion behavior])
+	fi
 ])
 
 dnl
diff --git a/include/ircd/assert.h b/include/ircd/assert.h
index 18813abb5..70293589e 100644
--- a/include/ircd/assert.h
+++ b/include/ircd/assert.h
@@ -19,43 +19,61 @@
 #pragma once
 #define HAVE_IRCD_ASSERT_H
 
-namespace ircd
-{
-	void debugtrap();
-}
-
+/// This file has to be included prior to the standard library assert headers
 #if defined(RB_ASSERT) && defined(_ASSERT_H_DECLS) && defined(RB_DEBUG)
 	#error "Do not include <assert.h> or <cassert> first."
 #endif
 
+/// Define an indicator for whether we override standard assert() behavior in
+/// this build if the conditions are appropriate.
 #if defined(RB_ASSERT) && !defined(NDEBUG)
-#define _ASSERT_H_DECLS
+	#define IRCD_ASSERT_OVERRIDE
+	#define _ASSERT_H_DECLS
+#endif
 
+// Our utils
+namespace ircd
+{
+	void print_assertion(const char *const &, const char *const &, const unsigned &, const char *const &) noexcept;
+	void debugtrap() noexcept;
+}
+
+/// Override the standard assert behavior, if enabled, to trap into the
+/// debugger as close as possible to the offending site.
+///
+#if defined(IRCD_ASSERT_OVERRIDE) && defined(RB_ASSERT_INTRINSIC)
+extern "C" inline void
+__attribute__((flatten, always_inline, gnu_inline, artificial))
+__assert_fail(const char *__assertion,
+              const char *__file,
+              unsigned int __line,
+              const char *__function)
+{
+	ircd::print_assertion(__assertion, __file, __line, __function);
+	ircd::debugtrap();
+}
+#endif
+
+/// Override the standard assert behavior to take one of several different
+/// actions as defined in our internal assert.cc unit. When trapping assert
+/// is disabled this path will be used instead.
+///
+#if defined(IRCD_ASSERT_OVERRIDE) && !defined(RB_ASSERT_INTRINSIC)
 extern "C" void
 __attribute__((visibility("default")))
 __assert_fail(const char *__assertion,
               const char *__file,
               unsigned int __line,
               const char *__function);
-
-extern "C" void
-__attribute__((visibility("default")))
-__assert_perror_fail(int __errnum,
-                     const char *__file,
-                     unsigned int __line,
-                     const char *__function);
-
-extern "C" void
-__attribute__((visibility("default")))
-__assert(const char *__assertion,
-         const char *__file,
-         int __line);
-
 #endif
 
+/// Intrinsic to halt execution for examination by a tracing debugger without
+/// aborting the program.
+///
 extern inline void
 __attribute__((always_inline, gnu_inline, artificial))
 ircd::debugtrap()
+noexcept
 {
 	#if defined(__clang__)
 		static_assert(__has_builtin(__builtin_debugtrap));
diff --git a/ircd/assert.cc b/ircd/assert.cc
index 703d47459..09f65ce13 100644
--- a/ircd/assert.cc
+++ b/ircd/assert.cc
@@ -10,30 +10,7 @@
 
 #include <RB_INC_SIGNAL_H
 
-#if !defined(NDEBUG) && defined(RB_ASSERT)
-void
-__assert(const char *__assertion,
-         const char *__file,
-         int __line)
-{
-	__assert_fail(__assertion, __file, __line, "<no function>");
-}
-#endif
-
-#if !defined(NDEBUG) && defined(RB_ASSERT)
-void
-__assert_perror_fail(int __errnum,
-                     const char *__file,
-                     unsigned int __line,
-                     const char *__function)
-{
-	char buf[32];
-	snprintf(buf, sizeof(buf), "perror #%d: ", __errnum);
-	__assert_fail(buf, __file, __line, __function);
-}
-#endif
-
-#if !defined(NDEBUG) && defined(RB_ASSERT)
+#ifdef IRCD_ASSERT_OVERRIDE
 #ifdef __clang__
 #pragma clang diagnostic push
 #pragma clang diagnostic ignored "-Wunreachable-code"
@@ -44,12 +21,7 @@ __assert_fail(const char *__assertion,
               unsigned int __line,
               const char *__function)
 {
-	if(strcmp(__assertion, "critical") != 0)
-		fprintf(stderr, "\nassertion failed [%s +%u] %s :%s\n",
-		        __file,
-		        __line,
-		        __function,
-		        __assertion);
+	ircd::print_assertion(__assertion, __file, __line, __function);
 
 	if(ircd::soft_assert)
 		return;
@@ -97,3 +69,20 @@ __assert_fail(const char *__assertion,
 #pragma clang diagnostic pop
 #endif __clang__
 #endif
+
+void
+ircd::print_assertion(const char *const &__assertion,
+                      const char *const &__file,
+                      const unsigned &__line,
+                      const char *const &__function)
+noexcept
+{
+	if(strcmp(__assertion, "critical") == 0)
+		return;
+
+	fprintf(stderr, "\nassertion failed [%s +%u] %s :%s\n",
+	        __file,
+	        __line,
+	        __function,
+	        __assertion);
+}