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Initial implementation of exiting CompilationCallback 

This should save all argument registers on entry and restore on exit, despite
that, simple things seem to work!!!

llvm-svn: 18161
This commit is contained in:
Chris Lattner 2004-11-23 18:49:46 +00:00
parent febc3eb8fa
commit a8936af13e
1 changed files with 24 additions and 9 deletions
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33
llvm/lib/Target/PowerPC/PPC32JITInfo.cpp
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@ -54,16 +54,19 @@ static void CompilationCallback() {
//uint64_t FPRegs[13];
unsigned *CameFromStub = (unsigned*)__builtin_return_address(0);
unsigned *CameFromOrig = (unsigned*)__builtin_return_address(1);
unsigned *CCStackPtr = (unsigned*)__builtin_frame_address(0);
//unsigned *StubStackPtr = (unsigned*)__builtin_frame_address(1);
unsigned *OrigStackPtr = (unsigned*)__builtin_frame_address(2);
// Adjust our pointers to the branches, not the return addresses.
--CameFromStub; --CameFromOrig;
// Adjust pointer to the branch, not the return address.
--CameFromStub;
void *Target = JITCompilerFunction(CameFromStub);
// Check to see if CameFromOrig[-1] is a 'bl' instruction, and if we can
// rewrite it to branch directly to the destination. If so, rewrite it so it
// does not need to go through the stub anymore.
unsigned CameFromOrigInst = *CameFromOrig;
unsigned CameFromOrigInst = CameFromOrig[-1];
if ((CameFromOrigInst >> 26) == 18) { // Direct call.
intptr_t Offset = ((intptr_t)Target-(intptr_t)CameFromOrig) >> 2;
if (Offset >= -(1 << 23) && Offset < (1 << 23)) { // In range?
@ -71,26 +74,38 @@ static void CompilationCallback() {
// Clear the original target out:
CameFromOrigInst &= (63 << 26) | 3;
CameFromOrigInst |= Offset << 2;
*CameFromOrig = CameFromOrigInst;
CameFromOrig[-1] = CameFromOrigInst;
}
}
// Locate the start of the stub. If this is a short call, adjust backwards
// the short amount, otherwise the full amount.
bool isShortStub = (*CameFromStub >> 26) == 18;
CameFromStub -= isShortStub ? 3 : 7;
CameFromStub -= isShortStub ? 2 : 6;
// Rewrite the stub with an unconditional branch to the target, for any users
// who took the address of the stub.
EmitBranchToAt(CameFromStub, Target, false);
// Change the SP so that we pop two stack frames off when we return.
*CCStackPtr = (intptr_t)OrigStackPtr;
// Put the address of the stub and the LR value that originally came into the
// stub in a place that is easy to get on the stack after we restore all regs.
CCStackPtr[2] = (intptr_t)CameFromStub;
CCStackPtr[1] = (intptr_t)CameFromOrig;
// FIXME: Need to restore the registers from IntRegs/FPRegs.
// FIXME: Need to pop two frames off of the stack and return to a place where
// we magically reexecute the call, or jump directly to the caller. This
// requires inline asm majik.
assert(0 && "CompilationCallback not finished yet!");
// Note, this is not a standard epilog!
#if defined(__POWERPC__) || defined (__ppc__) || defined(_POWER)
__asm__ __volatile__ ("lwz r0,4(r1)\n" // Get CameFromOrig (LR into stub)
"mtlr r0\n" // Put it in the LR register
"lwz r0,8(r1)\n" // Get "CameFromStub"
"mtctr r0\n" // Put it into the CTR register
"lwz r1,0(r1)\n" // Pop two frames off
"bctr\n" ::); // Return to stub!
#endif
}