JVM Image Fixes (eclipse-openj9#20)

* Updated JVMImageHeader and fixed reading from file * Formatting fixup * Moved the header's buffer to the stack Signed-off-by: Brady Jessup <[email protected]>
tajila · Jun 27, 2019 · 3ae4fdf · 3ae4fdf
1 parent f433aec
commit 3ae4fdf
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Showing 2 changed files with 9 additions and 8 deletions.
diff --git a/runtime/oti/jvmimage.h b/runtime/oti/jvmimage.h
@@ -46,7 +46,7 @@ struct JVMImageHeader;
  */
 typedef struct JVMImageHeader {
 	UDATA imageSize; /* image size in bytes */
-	uintptr_t heapAddress;
+	uintptr_t imageAddress;
 	J9WSRP classLoaderTable;
 	J9WSRP classSegmentTable;
 	J9WSRP classPathEntryTable;

diff --git a/runtime/vm/JVMImage.cpp b/runtime/vm/JVMImage.cpp
@@ -40,7 +40,7 @@ JVMImage::~JVMImage()
 {
 	PORT_ACCESS_FROM_JAVAVM(_vm);
 
-	j9mem_free_memory((void*)_jvmImageHeader);
+	j9mem_free_memory((void *)_jvmImageHeader);
 }
 
 bool
@@ -122,6 +122,7 @@ JVMImage::allocateImageMemory(UDATA size)
 	}
 
 	_jvmImageHeader->imageSize = size;
+	_jvmImageHeader->imageAddress = (uintptr_t)_jvmImageHeader;
 
 	return _jvmImageHeader;
 }
@@ -143,8 +144,6 @@ JVMImage::initializeHeap(void)
 		return NULL;
 	}
 
-	_jvmImageHeader->heapAddress = (uintptr_t)_heap;
-
 	return _heap;
 }
 
@@ -329,15 +328,17 @@ JVMImage::readImageFromFile(void)
 	}
 
 	/* Read image header then mmap the rest of the image (heap) into memory */
-	omrfile_read(fileDescriptor, (void *)_jvmImageHeader, sizeof(JVMImageHeader));
+	/* TODO: Should only read imageAddress and size because that is the only data we need for mmap */
+	JVMImageHeader imageHeaderBuffer;
+	omrfile_read(fileDescriptor, (void *)&imageHeaderBuffer, sizeof(JVMImageHeader));
 	uint64_t fileSize = omrfile_flength(fileDescriptor);
-	if (_jvmImageHeader->imageSize != fileSize) {
+	if (imageHeaderBuffer.imageSize != fileSize) {
 		return false;
 	}
 
 	_jvmImageHeader = (JVMImageHeader *)mmap(
-		(void *)_jvmImageHeader->heapAddress,
-		_jvmImageHeader->imageSize,
+		(void *)imageHeaderBuffer.imageAddress,
+		imageHeaderBuffer.imageSize,
 		PROT_READ, MAP_PRIVATE, fileDescriptor, 0);
 	_heap = (J9Heap *)(_jvmImageHeader + 1);