mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-08-18 12:29:21 +00:00
the stub will resolve. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@49814 91177308-0d34-0410-b5e6-96231b3b80d8
165 lines
6.1 KiB
C++
165 lines
6.1 KiB
C++
//===-- ARMJITInfo.cpp - Implement the JIT interfaces for the ARM target --===//
|
|
//
|
|
// The LLVM Compiler Infrastructure
|
|
//
|
|
// This file is distributed under the University of Illinois Open Source
|
|
// License. See LICENSE.TXT for details.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
// This file implements the JIT interfaces for the ARM target.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#define DEBUG_TYPE "jit"
|
|
#include "ARMJITInfo.h"
|
|
#include "ARMRelocations.h"
|
|
#include "ARMSubtarget.h"
|
|
#include "llvm/Function.h"
|
|
#include "llvm/CodeGen/MachineCodeEmitter.h"
|
|
#include "llvm/Config/alloca.h"
|
|
#include <cstdlib>
|
|
using namespace llvm;
|
|
|
|
void ARMJITInfo::replaceMachineCodeForFunction(void *Old, void *New) {
|
|
abort();
|
|
}
|
|
|
|
/// JITCompilerFunction - This contains the address of the JIT function used to
|
|
/// compile a function lazily.
|
|
static TargetJITInfo::JITCompilerFn JITCompilerFunction;
|
|
|
|
// CompilationCallback stub - We can't use a C function with inline assembly in
|
|
// it, because we the prolog/epilog inserted by GCC won't work for us. Instead,
|
|
// write our own wrapper, which does things our way, so we have complete control
|
|
// over register saving and restoring.
|
|
extern "C" {
|
|
#if defined(__arm__)
|
|
void ARMCompilationCallback(void);
|
|
asm(
|
|
".text\n"
|
|
".align 2\n"
|
|
".globl ARMCompilationCallback\n"
|
|
"ARMCompilationCallback:\n"
|
|
// save main registers
|
|
"mov ip, sp\n"
|
|
"stmfd sp!, {fp, ip, lr, pc}\n"
|
|
"sub fp, ip, #4\n"
|
|
// arguments to Compilation Callback
|
|
// r0 - our lr (address of the call instruction in stub plus 4)
|
|
// r1 - stub's lr (address of instruction that called the stub plus 4)
|
|
"mov r0, fp\n" // stub's frame
|
|
"mov r1, lr\n" // stub's lr
|
|
"bl ARMCompilationCallbackC\n"
|
|
// restore main registers
|
|
"ldmfd sp, {fp, sp, pc}\n");
|
|
#else // Not an ARM host
|
|
void ARMCompilationCallback() {
|
|
assert(0 && "Cannot call ARMCompilationCallback() on a non-ARM arch!\n");
|
|
abort();
|
|
}
|
|
#endif
|
|
}
|
|
|
|
/// ARMCompilationCallbackC - This is the target-specific function invoked by the
|
|
/// function stub when we did not know the real target of a call. This function
|
|
/// must locate the start of the stub or call site and pass it into the JIT
|
|
/// compiler function.
|
|
extern "C" void ARMCompilationCallbackC(intptr_t *StackPtr, intptr_t RetAddr) {
|
|
intptr_t *RetAddrLoc = &StackPtr[-1];
|
|
|
|
assert(*RetAddrLoc == RetAddr &&
|
|
"Could not find return address on the stack!");
|
|
#if 0
|
|
DOUT << "In callback! Addr=" << (void*)RetAddr
|
|
<< " FP=" << (void*)StackPtr
|
|
<< ": Resolving call to function: "
|
|
<< TheVM->getFunctionReferencedName((void*)RetAddr) << "\n";
|
|
#endif
|
|
intptr_t Addr = RetAddr - 4;
|
|
|
|
intptr_t NewVal = (intptr_t)JITCompilerFunction((void*)Addr);
|
|
|
|
// Rewrite the call target... so that we don't end up here every time we
|
|
// execute the call.
|
|
*(intptr_t *)Addr = NewVal;
|
|
|
|
// Change the return address to reexecute the branch and link instruction...
|
|
*RetAddrLoc -= 12;
|
|
}
|
|
|
|
TargetJITInfo::LazyResolverFn
|
|
ARMJITInfo::getLazyResolverFunction(JITCompilerFn F) {
|
|
JITCompilerFunction = F;
|
|
return ARMCompilationCallback;
|
|
}
|
|
|
|
void *ARMJITInfo::emitFunctionStub(const Function* F, void *Fn,
|
|
MachineCodeEmitter &MCE) {
|
|
unsigned addr = (intptr_t)Fn;
|
|
// If this is just a call to an external function, emit a branch instead of a
|
|
// call. The code is the same except for one bit of the last instruction.
|
|
if (Fn != (void*)(intptr_t)ARMCompilationCallback) {
|
|
// branch to the corresponding function addr
|
|
// the stub is 8-byte size and 4-aligned
|
|
MCE.startFunctionStub(F, 8, 4);
|
|
MCE.emitWordLE(0xE51FF004); // LDR PC, [PC,#-4]
|
|
MCE.emitWordLE(addr); // addr of function
|
|
} else {
|
|
// branch and link to the corresponding function addr
|
|
// the stub is 20-byte size and 4-aligned
|
|
MCE.startFunctionStub(F, 20, 4);
|
|
MCE.emitWordLE(0xE92D4800); // STMFD SP!, [R11, LR]
|
|
MCE.emitWordLE(0xE28FE004); // ADD LR, PC, #4
|
|
MCE.emitWordLE(0xE51FF004); // LDR PC, [PC,#-4]
|
|
MCE.emitWordLE(addr); // addr of function
|
|
MCE.emitWordLE(0xE8BD8800); // LDMFD SP!, [R11, PC]
|
|
}
|
|
|
|
return MCE.finishFunctionStub(F);
|
|
}
|
|
|
|
/// relocate - Before the JIT can run a block of code that has been emitted,
|
|
/// it must rewrite the code to contain the actual addresses of any
|
|
/// referenced global symbols.
|
|
void ARMJITInfo::relocate(void *Function, MachineRelocation *MR,
|
|
unsigned NumRelocs, unsigned char* GOTBase) {
|
|
for (unsigned i = 0; i != NumRelocs; ++i, ++MR) {
|
|
void *RelocPos = (char*)Function + MR->getMachineCodeOffset();
|
|
intptr_t ResultPtr = (intptr_t)MR->getResultPointer();
|
|
switch ((ARM::RelocationType)MR->getRelocationType()) {
|
|
case ARM::reloc_arm_relative: {
|
|
// It is necessary to calculate the correct PC relative value. We
|
|
// subtract the base addr from the target addr to form a byte offset.
|
|
ResultPtr = ResultPtr-(intptr_t)RelocPos-8;
|
|
// If the result is positive, set bit U(23) to 1.
|
|
if (ResultPtr >= 0)
|
|
*((unsigned*)RelocPos) |= 1 << 23;
|
|
else {
|
|
// otherwise, obtain the absolute value and set
|
|
// bit U(23) to 0.
|
|
ResultPtr *= -1;
|
|
*((unsigned*)RelocPos) &= 0xFF7FFFFF;
|
|
}
|
|
// set the immed value calculated
|
|
*((unsigned*)RelocPos) |= (unsigned)ResultPtr;
|
|
// set register Rn to PC
|
|
*((unsigned*)RelocPos) |= 0xF << 16;
|
|
break;
|
|
}
|
|
case ARM::reloc_arm_branch: {
|
|
// It is necessary to calculate the correct value of signed_immed_24
|
|
// field. We subtract the base addr from the target addr to form a
|
|
// byte offset, which must be inside the range -33554432 and +33554428.
|
|
// Then, we set the signed_immed_24 field of the instruction to bits
|
|
// [25:2] of the byte offset. More details ARM-ARM p. A4-11.
|
|
ResultPtr = ResultPtr-(intptr_t)RelocPos-8;
|
|
ResultPtr = (ResultPtr & 0x03FFFFFC) >> 2;
|
|
assert(ResultPtr >= -33554432 && ResultPtr <= 33554428);
|
|
*((unsigned*)RelocPos) |= ResultPtr;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
}
|