121 lines
4.0 KiB
C++
121 lines
4.0 KiB
C++
/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
|
|
*
|
|
* The contents of this file are subject to the Netscape Public License
|
|
* Version 1.0 (the "NPL"); you may not use this file except in
|
|
* compliance with the NPL. You may obtain a copy of the NPL at
|
|
* http://www.mozilla.org/NPL/
|
|
*
|
|
* Software distributed under the NPL is distributed on an "AS IS" basis,
|
|
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the NPL
|
|
* for the specific language governing rights and limitations under the
|
|
* NPL.
|
|
*
|
|
* The Initial Developer of this code under the NPL is Netscape
|
|
* Communications Corporation. Portions created by Netscape are
|
|
* Copyright (C) 1998 Netscape Communications Corporation. All Rights
|
|
* Reserved.
|
|
*/
|
|
#include "NativeMethodStubs.h"
|
|
#include "NativeCodeCache.h"
|
|
#include "MemoryAccess.h"
|
|
#include "jni.h"
|
|
|
|
extern JNIEnv *jniEnv;
|
|
extern void throwJNIExceptionIfNeeded();
|
|
|
|
// XXX This will eventually have to be done on a per-thread basis!!
|
|
static Uint32 JNIReturnAddressInteger = 0;
|
|
static void *JNIReturnAddress = &JNIReturnAddressInteger;
|
|
|
|
// Stub sizes
|
|
static const JNIStaticStubSize = 34;
|
|
static const JNIInstanceStubSize = 32;
|
|
|
|
// x86 opcodes that we're interested in
|
|
static const Uint8 popEax = 0x58;
|
|
static const Uint8 pushl = 0x68;
|
|
static const Uint8 jmpl = 0xe9;
|
|
static const Uint8 pushEax = 0x50;
|
|
static const Uint8 calll = 0xe8;
|
|
static const Uint8 moveFromEax = 0xa3;
|
|
|
|
static const Uint16 jmplIndirectLow = 0xff;
|
|
static const Uint16 jmplIndirectHigh = 0x25;
|
|
|
|
#define writeRelativeDisplacement(symbol) \
|
|
writeLittleWordUnaligned(where, reinterpret_cast<Uint32>(symbol) - Uint32(where + 4));\
|
|
where += 4;
|
|
|
|
#define writeGlobalLocation(symbol) \
|
|
writeLittleWordUnaligned(where, reinterpret_cast<Uint32>(symbol));\
|
|
where += 4;
|
|
|
|
/* Generate stub glue for a native JNI function.
|
|
* The net effect is to generate code that does the following:
|
|
*
|
|
* pop eax // Save return address in EAX
|
|
* mov JNIReturnAddress, eax // Tuck return address safely away
|
|
* push declaringClass // Push declaring class; static methods only
|
|
* push JNIenv // Push JNI pointer
|
|
* call nativeMethod // Jump to the actual JNI native method
|
|
* push eax // Store the return value on the stack
|
|
* call throwJNIExceptionIfNeeded // Check and throw JNI exceptions if needed
|
|
* pop eax // Restore the return value
|
|
* jmp [JNIReturnAddress] // jump to previously stored return address
|
|
*/
|
|
void *generateJNIGlue(const Method &method,
|
|
void *nativeFunction)
|
|
{
|
|
void* stub;
|
|
int stubSize = (method.getModifiers() & CR_METHOD_STATIC) ?
|
|
JNIStaticStubSize : JNIInstanceStubSize;
|
|
|
|
assert(method.getModifiers() & CR_METHOD_NATIVE);
|
|
assert(nativeFunction);
|
|
|
|
// Write out the JNI stub
|
|
stub = NativeCodeCache::sNativeCodeCache.acquireMemory(stubSize);
|
|
|
|
Uint8* where = (Uint8*) stub;
|
|
*where++ = popEax; // popl eax
|
|
|
|
*where++ = moveFromEax;
|
|
writeGlobalLocation(JNIReturnAddress);
|
|
|
|
|
|
// We're pushing arguments right-to-left, so the jclass
|
|
// argument is pushed before the JNIEnv.
|
|
if (method.getModifiers() & CR_METHOD_STATIC) {
|
|
*where++ = pushl; // pushl
|
|
writeGlobalLocation((method.getDeclaringClass()));
|
|
}
|
|
|
|
*where++ = pushl; // pushl
|
|
writeGlobalLocation(jniEnv);
|
|
|
|
// Put the return address back on the stack
|
|
//*where++ = pushEax; // push eax
|
|
|
|
*where++ = calll; // call
|
|
writeRelativeDisplacement(nativeFunction);
|
|
|
|
// Store the return value on the stack
|
|
*where++ = pushEax; // push eax
|
|
|
|
// Call throwJNIExceptionIfNeeded
|
|
*where++ = calll;
|
|
writeRelativeDisplacement(&throwJNIExceptionIfNeeded);
|
|
|
|
// Restore return value
|
|
*where++ = popEax; // pop eax
|
|
|
|
// Get back to where we once belonged...
|
|
*where++ = jmplIndirectLow;
|
|
*where++ = jmplIndirectHigh;
|
|
writeGlobalLocation(JNIReturnAddress);
|
|
|
|
return stub;
|
|
}
|
|
|
|
|