From 5dbd89d2aaa03659bed6f31f5b050fcc11c1c502 Mon Sep 17 00:00:00 2001
From: Jonas 'Sortie' Termansen <sortie@maxsi.org>
Date: Wed, 26 Mar 2014 03:01:16 +0100
Subject: [PATCH] Delay heap initialization until first heap expansion.

---
 kernel/kernel.cpp     |  3 ---
 libc/include/malloc.h |  4 +---
 libc/init/init.cpp    |  3 ---
 libc/stdlib/heap.cpp  | 36 ++++++++++--------------------------
 4 files changed, 11 insertions(+), 35 deletions(-)

diff --git a/kernel/kernel.cpp b/kernel/kernel.cpp
index 3f5cfc41..6e61364e 100644
--- a/kernel/kernel.cpp
+++ b/kernel/kernel.cpp
@@ -295,9 +295,6 @@ extern "C" void KernelInit(unsigned long magic, multiboot_info_t* bootinfo)
 	// Initialize the interrupt handler table and enable interrupts.
 	Interrupt::Init();
 
-	// Initialize the kernel heap.
-	_init_heap();
-
 	// Load the kernel symbols if provided by the bootloader.
 	do if ( bootinfo->flags & MULTIBOOT_INFO_ELF_SHDR )
 	{
diff --git a/libc/include/malloc.h b/libc/include/malloc.h
index 80bc06b7..2006ead4 100644
--- a/libc/include/malloc.h
+++ b/libc/include/malloc.h
@@ -1,6 +1,6 @@
 /*******************************************************************************
 
-    Copyright(C) Jonas 'Sortie' Termansen 2012.
+    Copyright(C) Jonas 'Sortie' Termansen 2012, 2014.
 
     This file is part of the Sortix C Library.
 
@@ -29,8 +29,6 @@
 
 __BEGIN_DECLS
 
-void _init_heap();
-
 __END_DECLS
 
 #endif
diff --git a/libc/init/init.cpp b/libc/init/init.cpp
index 44a7eadc..f9d42345 100644
--- a/libc/init/init.cpp
+++ b/libc/init/init.cpp
@@ -55,9 +55,6 @@ extern "C" void initialize_standard_library(int argc, char* argv[])
 	// Initialize pthreads and stuff like thread-local storage.
 	pthread_initialize();
 
-	// Initialize the dynamic heap.
-	_init_heap();
-
 	// Initialize stdio.
 	init_stdio();
 
diff --git a/libc/stdlib/heap.cpp b/libc/stdlib/heap.cpp
index 36097a78..af5dd0ec 100644
--- a/libc/stdlib/heap.cpp
+++ b/libc/stdlib/heap.cpp
@@ -197,9 +197,9 @@ struct Chunk;
 struct Trailer;
 
 #if __STDC_HOSTED__
-pthread_mutex_t heaplock;
+pthread_mutex_t heaplock = PTHREAD_MUTEX_INITIALIZER;
 #elif defined(__is_sortix_kernel)
-Sortix::kthread_mutex_t heaplock;
+Sortix::kthread_mutex_t heaplock = Sortix::KTHREAD_MUTEX_INITIALIZER;
 #endif
 
 // The location where the heap originally grows from.
@@ -212,14 +212,14 @@ static uintptr_t wilderness;
 #endif
 
 // How many bytes remain in the wilderness.
-size_t wildernesssize;
+size_t wildernesssize = 0;
 
 // How many bytes are the heap allow to grow to (including wilderness).
-size_t heapmaxsize;
+size_t heapmaxsize = SIZE_MAX;
 
 // How many bytes are currently used for chunks in the heap, which
 // excludes the wilderness.
-size_t heapsize;
+size_t heapsize = 0;
 
 // bins[N] contain a linked list of chunks that are at least 2^(N+1)
 // bytes, but less than 2^(N+2) bytes. By selecting the proper bin in
@@ -227,7 +227,7 @@ size_t heapsize;
 Chunk* bins[NUMBINS];
 
 // Bit N is set if bin[N] contains a chunk.
-size_t bincontainschunks;
+size_t bincontainschunks = 0;
 
 static bool IsGoodHeapPointer(void* ptr, size_t size)
 {
@@ -397,26 +397,6 @@ static bool ValidateHeap()
 	return true;
 }
 
-//
-// This is where the actual memory allocation algorithm starts.
-//
-
-extern "C" void _init_heap()
-{
-	heapstart = GetHeapStart();
-	heapmaxsize = SIZE_MAX;
-	heapsize = 0;
-	wilderness = heapstart;
-	wildernesssize = 0;
-	for ( size_t i = 0; i < NUMBINS; i++ ) { bins[i] = NULL; }
-	bincontainschunks = 0;
-#if __STDC_HOSTED__
-	heaplock = PTHREAD_MUTEX_INITIALIZER;
-#elif defined(__is_sortix_kernel)
-	heaplock = Sortix::KTHREAD_MUTEX_INITIALIZER;
-#endif
-}
-
 // Attempts to expand the wilderness such that it contains at least
 // bytesneeded bytes. This is done by mapping new pages onto into the
 // virtual address-space.
@@ -424,6 +404,10 @@ static bool ExpandWilderness(size_t bytesneeded)
 {
 	if ( bytesneeded <= wildernesssize ) { return true; }
 
+	// Delayed initialization of the heap.
+	if ( heapstart == 0 && wilderness == 0 && !heapsize )
+		heapstart = wilderness = GetHeapStart();
+
 	bytesneeded -= wildernesssize;
 
 	// Align the increase on page boundaries.