Initial Contribution

1 files changed, 115 insertions, 0 deletions

diff --git a/vm/LinearAlloc.h b/vm/LinearAlloc.h
new file mode 100644
index 000000000..9c1d0962e
--- /dev/null
+++ b/vm/LinearAlloc.h
@@ -0,0 +1,115 @@
+/*
+ * Copyright (C) 2008 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+/*
+ * Simple linear memory allocator.
+ */
+#ifndef _DALVIK_LINEARALLOC
+#define _DALVIK_LINEARALLOC
+
+/*
+ * If this is set, we create additional data structures and make many
+ * additional mprotect() calls.
+ * (this breaks the debugger because the debugBreakpointCount cannot be updated)
+ */
+#define ENFORCE_READ_ONLY   false
+
+/*
+ * Linear allocation state.  We could tuck this into the start of the
+ * allocated region, but that would prevent us from sharing the rest of
+ * that first page.
+ */
+typedef struct LinearAllocHdr {
+    int     curOffset;          /* offset where next data goes */
+    pthread_mutex_t lock;       /* controls updates to this struct */
+
+    char*   mapAddr;            /* start of mmap()ed region */
+    int     mapLength;          /* length of region */
+    int     firstOffset;        /* for chasing through */
+
+    short*  writeRefCount;      /* for ENFORCE_READ_ONLY */
+} LinearAllocHdr;
+
+
+/*
+ * Create a new alloc region.
+ */
+LinearAllocHdr* dvmLinearAllocCreate(Object* classLoader);
+
+/*
+ * Destroy a region.
+ */
+void dvmLinearAllocDestroy(Object* classLoader);
+
+/*
+ * Allocate a chunk of memory.  The memory will be zeroed out.
+ *
+ * For ENFORCE_READ_ONLY, call dvmLinearReadOnly on the result.
+ */
+void* dvmLinearAlloc(Object* classLoader, size_t size);
+
+/*
+ * Reallocate a chunk.  The original storage is not released, but may be
+ * erased to aid debugging.
+ *
+ * For ENFORCE_READ_ONLY, call dvmLinearReadOnly on the result.  Also, the
+ * caller should probably mark the "mem" argument read-only before calling.
+ */
+void* dvmLinearRealloc(Object* classLoader, void* mem, size_t newSize);
+
+/* don't call these directly */
+void dvmLinearSetReadOnly(Object* classLoader, void* mem);
+void dvmLinearSetReadWrite(Object* classLoader, void* mem);
+
+/*
+ * Mark a chunk of memory from Alloc or Realloc as read-only.  This must
+ * be done after all changes to the block of memory have been made.  This
+ * actually operates on a page granularity.
+ */
+INLINE void dvmLinearReadOnly(Object* classLoader, void* mem)
+{
+    if (ENFORCE_READ_ONLY && mem != NULL)
+        dvmLinearSetReadOnly(classLoader, mem);
+}
+
+/*
+ * Make a chunk of memory writable again.
+ */
+INLINE void dvmLinearReadWrite(Object* classLoader, void* mem)
+{
+    if (ENFORCE_READ_ONLY && mem != NULL)
+        dvmLinearSetReadWrite(classLoader, mem);
+}
+
+/*
+ * Free a chunk.  Does not increase available storage, but the freed area
+ * may be erased to aid debugging.
+ */
+void dvmLinearFree(Object* classLoader, void* mem);
+
+/*
+ * Helper function; allocates new storage and copies "str" into it.
+ *
+ * For ENFORCE_READ_ONLY, do *not* call dvmLinearReadOnly on the result.
+ * This is done automatically.
+ */
+char* dvmLinearStrdup(Object* classLoader, const char* str);
+
+/*
+ * Dump the contents of a linear alloc area.
+ */
+void dvmLinearAllocDump(Object* classLoader);
+
+#endif /*_DALVIK_LINEARALLOC*/