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Preliminary support for X86-64 JIT stub codegen. 

llvm-svn: 35095
This commit is contained in:
Evan Cheng 2007-03-14 10:44:30 +00:00
parent d8c645b0ba
commit e1a95206e3
1 changed files with 35 additions and 3 deletions
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38
llvm/lib/Target/X86/X86JITInfo.cpp
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@ -205,9 +205,9 @@ extern "C" {
#ifdef _MSC_VER
extern "C" void X86CompilationCallback2() {
assert(sizeof(size_t) == 4); // FIXME: handle Win64
unsigned *RetAddrLoc = (unsigned *)_AddressOfReturnAddress();
intptr_t *RetAddrLoc = (intptr_t *)_AddressOfReturnAddress();
RetAddrLoc += 4; // skip over ret addr, edx, eax, ecx
unsigned RetAddr = *RetAddrLoc;
intptr_t RetAddr = *RetAddrLoc;
#else
extern "C" void X86CompilationCallback2(intptr_t *StackPtr, intptr_t RetAddr) {
intptr_t *RetAddrLoc = &StackPtr[1];
@ -219,7 +219,11 @@ extern "C" void X86CompilationCallback2(intptr_t *StackPtr, intptr_t RetAddr) {
bool isStub = ((unsigned char*)RetAddr)[0] == 0xCD;
// The call instruction should have pushed the return value onto the stack...
#ifdef __x86_64__
RetAddr--; // Backtrack to the reference itself...
#else
RetAddr -= 4; // Backtrack to the reference itself...
#endif
#if 0
DOUT << "In callback! Addr=" << (void*)RetAddr
@ -229,24 +233,41 @@ extern "C" void X86CompilationCallback2(intptr_t *StackPtr, intptr_t RetAddr) {
#endif
// Sanity check to make sure this really is a call instruction.
#ifdef __x86_64__
assert(((unsigned char*)RetAddr)[-2] == 0x41 &&"Not a call instr!");
assert(((unsigned char*)RetAddr)[-1] == 0xFF &&"Not a call instr!");
#else
assert(((unsigned char*)RetAddr)[-1] == 0xE8 &&"Not a call instr!");
#endif
intptr_t NewVal = (intptr_t)JITCompilerFunction((void*)RetAddr);
// Rewrite the call target... so that we don't end up here every time we
// execute the call.
*(unsigned *)RetAddr = (unsigned)(NewVal-RetAddr-4);
#ifdef __x86_64__
*(intptr_t *)(RetAddr - 0xa) = NewVal;
#else
*(intptr_t *)RetAddr = (intptr_t)(NewVal-RetAddr-4);
#endif
if (isStub) {
// If this is a stub, rewrite the call into an unconditional branch
// instruction so that two return addresses are not pushed onto the stack
// when the requested function finally gets called. This also makes the
// 0xCD byte (interrupt) dead, so the marker doesn't effect anything.
#ifdef __x86_64__
((unsigned char*)RetAddr)[0] = (2 | (4 << 3) | (3 << 6));
#else
((unsigned char*)RetAddr)[-1] = 0xE9;
#endif
}
// Change the return address to reexecute the call instruction...
#ifdef __x86_64__
*RetAddrLoc -= 0xd;
#else
*RetAddrLoc -= 5;
#endif
}
TargetJITInfo::LazyResolverFn
@ -291,10 +312,21 @@ void *X86JITInfo::emitFunctionStub(void *Fn, MachineCodeEmitter &MCE) {
return MCE.finishFunctionStub(0);
}
#ifdef __x86_64__
MCE.startFunctionStub(14, 4);
MCE.emitByte(0x49); // REX prefix
MCE.emitByte(0xB8+2); // movabsq r10
MCE.emitWordLE(((unsigned *)&Fn)[0]);
MCE.emitWordLE(((unsigned *)&Fn)[1]);
MCE.emitByte(0x41); // REX prefix
MCE.emitByte(0xFF); // callq *r10
MCE.emitByte(2 | (2 << 3) | (3 << 6));
#else
MCE.startFunctionStub(6, 4);
MCE.emitByte(0xE8); // Call with 32 bit pc-rel destination...
MCE.emitWordLE((intptr_t)Fn-MCE.getCurrentPCValue()-4);
#endif
MCE.emitByte(0xCD); // Interrupt - Just a marker identifying the stub!
return MCE.finishFunctionStub(0);