//
// The LLVM Compiler Infrastructure
//
-// This file was developed by the Raul Herbster and is distributed under the
-// University of Illinois Open Source License. See LICENSE.TXT for details.
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
//
//===----------------------------------------------------------------------===//
-#define DEBUG_TYPE "jit"
#include "ARMJITInfo.h"
+#include "ARMConstantPoolValue.h"
+#include "ARMMachineFunctionInfo.h"
#include "ARMRelocations.h"
-#include "ARMSubtarget.h"
-#include "llvm/CodeGen/MachineCodeEmitter.h"
-#include "llvm/Config/alloca.h"
+#include "MCTargetDesc/ARMBaseInfo.h"
+#include "llvm/CodeGen/JITCodeEmitter.h"
+#include "llvm/IR/Function.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/Memory.h"
+#include "llvm/Support/raw_ostream.h"
#include <cstdlib>
using namespace llvm;
+#define DEBUG_TYPE "jit"
+
void ARMJITInfo::replaceMachineCodeForFunction(void *Old, void *New) {
- abort();
+ report_fatal_error("ARMJITInfo::replaceMachineCodeForFunction");
}
/// JITCompilerFunction - This contains the address of the JIT function used to
/// compile a function lazily.
static TargetJITInfo::JITCompilerFn JITCompilerFunction;
+// Get the ASMPREFIX for the current host. This is often '_'.
+#ifndef __USER_LABEL_PREFIX__
+#define __USER_LABEL_PREFIX__
+#endif
+#define GETASMPREFIX2(X) #X
+#define GETASMPREFIX(X) GETASMPREFIX2(X)
+#define ASMPREFIX GETASMPREFIX(__USER_LABEL_PREFIX__)
+
// 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.
+// it, because the prolog/epilog inserted by GCC won't work for us. (We need
+// to preserve more context and manipulate the stack directly). 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);
+ void ARMCompilationCallback();
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
+ ".globl " ASMPREFIX "ARMCompilationCallback\n"
+ ASMPREFIX "ARMCompilationCallback:\n"
+ // Save caller saved registers since they may contain stuff
+ // for the real target function right now. We have to act as if this
+ // whole compilation callback doesn't exist as far as the caller is
+ // concerned, so we can't just preserve the callee saved regs.
+ "stmdb sp!, {r0, r1, r2, r3, lr}\n"
+#if (defined(__VFP_FP__) && !defined(__SOFTFP__))
+ "vstmdb sp!, {d0, d1, d2, d3, d4, d5, d6, d7}\n"
+#endif
+ // The LR contains the address of the stub function on entry.
+ // pass it as the argument to the C part of the callback
+ "mov r0, lr\n"
+ "sub sp, sp, #4\n"
+ // Call the C portion of the callback
+ "bl " ASMPREFIX "ARMCompilationCallbackC\n"
+ "add sp, sp, #4\n"
+ // Restoring the LR to the return address of the function that invoked
+ // the stub and de-allocating the stack space for it requires us to
+ // swap the two saved LR values on the stack, as they're backwards
+ // for what we need since the pop instruction has a pre-determined
+ // order for the registers.
+ // +--------+
+ // 0 | LR | Original return address
+ // +--------+
+ // 1 | LR | Stub address (start of stub)
+ // 2-5 | R3..R0 | Saved registers (we need to preserve all regs)
+ // 6-20 | D0..D7 | Saved VFP registers
+ // +--------+
+ //
+#if (defined(__VFP_FP__) && !defined(__SOFTFP__))
+ // Restore VFP caller-saved registers.
+ "vldmia sp!, {d0, d1, d2, d3, d4, d5, d6, d7}\n"
+#endif
+ //
+ // We need to exchange the values in slots 0 and 1 so we can
+ // return to the address in slot 1 with the address in slot 0
+ // restored to the LR.
+ "ldr r0, [sp,#20]\n"
+ "ldr r1, [sp,#16]\n"
+ "str r1, [sp,#20]\n"
+ "str r0, [sp,#16]\n"
+ // Return to the (newly modified) stub to invoke the real function.
+ // The above twiddling of the saved return addresses allows us to
+ // deallocate everything, including the LR the stub saved, with two
+ // updating load instructions.
+ "ldmia sp!, {r0, r1, r2, r3, lr}\n"
+ "ldr pc, [sp], #4\n"
+ );
+#else // Not an ARM host
void ARMCompilationCallback() {
- assert(0 && "Cannot call ARMCompilationCallback() on a non-ARM arch!\n");
- abort();
+ llvm_unreachable("Cannot call ARMCompilationCallback() on a non-ARM arch!");
}
#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);
+/// 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 StubAddr) {
+ // Get the address of the compiled code for this function.
+ intptr_t NewVal = (intptr_t)JITCompilerFunction((void*)StubAddr);
// 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;
+ // execute the call. We're replacing the first two instructions of the
+ // stub with:
+ // ldr pc, [pc,#-4]
+ // <addr>
+ if (!sys::Memory::setRangeWritable((void*)StubAddr, 8)) {
+ llvm_unreachable("ERROR: Unable to mark stub writable");
+ }
+ *(intptr_t *)StubAddr = 0xe51ff004; // ldr pc, [pc, #-4]
+ *(intptr_t *)(StubAddr+4) = NewVal;
+ if (!sys::Memory::setRangeExecutable((void*)StubAddr, 8)) {
+ llvm_unreachable("ERROR: Unable to mark stub executable");
+ }
}
TargetJITInfo::LazyResolverFn
return ARMCompilationCallback;
}
-void *ARMJITInfo::emitFunctionStub(void *Fn, MachineCodeEmitter &MCE) {
- unsigned addr = (intptr_t)Fn;
+void *ARMJITInfo::emitGlobalValueIndirectSym(const GlobalValue *GV, void *Ptr,
+ JITCodeEmitter &JCE) {
+ uint8_t Buffer[4];
+ uint8_t *Cur = Buffer;
+ MachineCodeEmitter::emitWordLEInto(Cur, (intptr_t)Ptr);
+ void *PtrAddr = JCE.allocIndirectGV(
+ GV, Buffer, sizeof(Buffer), /*Alignment=*/4);
+ addIndirectSymAddr(Ptr, (intptr_t)PtrAddr);
+ return PtrAddr;
+}
+
+TargetJITInfo::StubLayout ARMJITInfo::getStubLayout() {
+ // The stub contains up to 3 4-byte instructions, aligned at 4 bytes, and a
+ // 4-byte address. See emitFunctionStub for details.
+ StubLayout Result = {16, 4};
+ return Result;
+}
+
+void *ARMJITInfo::emitFunctionStub(const Function* F, void *Fn,
+ JITCodeEmitter &JCE) {
+ void *Addr;
// 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(8, 4);
- MCE.emitWordLE(0xE51FF004); // LDR PC, [PC,#-4]
- MCE.emitWordLE(addr); // addr of function
+ // Branch to the corresponding function addr.
+ if (IsPIC) {
+ // The stub is 16-byte size and 4-aligned.
+ intptr_t LazyPtr = getIndirectSymAddr(Fn);
+ if (!LazyPtr) {
+ // In PIC mode, the function stub is loading a lazy-ptr.
+ LazyPtr= (intptr_t)emitGlobalValueIndirectSym((const GlobalValue*)F, Fn, JCE);
+ DEBUG(if (F)
+ errs() << "JIT: Indirect symbol emitted at [" << LazyPtr
+ << "] for GV '" << F->getName() << "'\n";
+ else
+ errs() << "JIT: Stub emitted at [" << LazyPtr
+ << "] for external function at '" << Fn << "'\n");
+ }
+ JCE.emitAlignment(4);
+ Addr = (void*)JCE.getCurrentPCValue();
+ if (!sys::Memory::setRangeWritable(Addr, 16)) {
+ llvm_unreachable("ERROR: Unable to mark stub writable");
+ }
+ JCE.emitWordLE(0xe59fc004); // ldr ip, [pc, #+4]
+ JCE.emitWordLE(0xe08fc00c); // L_func$scv: add ip, pc, ip
+ JCE.emitWordLE(0xe59cf000); // ldr pc, [ip]
+ JCE.emitWordLE(LazyPtr - (intptr_t(Addr)+4+8)); // func - (L_func$scv+8)
+ sys::Memory::InvalidateInstructionCache(Addr, 16);
+ if (!sys::Memory::setRangeExecutable(Addr, 16)) {
+ llvm_unreachable("ERROR: Unable to mark stub executable");
+ }
+ } else {
+ // The stub is 8-byte size and 4-aligned.
+ JCE.emitAlignment(4);
+ Addr = (void*)JCE.getCurrentPCValue();
+ if (!sys::Memory::setRangeWritable(Addr, 8)) {
+ llvm_unreachable("ERROR: Unable to mark stub writable");
+ }
+ JCE.emitWordLE(0xe51ff004); // ldr pc, [pc, #-4]
+ JCE.emitWordLE((intptr_t)Fn); // addr of function
+ sys::Memory::InvalidateInstructionCache(Addr, 8);
+ if (!sys::Memory::setRangeExecutable(Addr, 8)) {
+ llvm_unreachable("ERROR: Unable to mark stub executable");
+ }
+ }
} else {
- // branch and link to the corresponding function addr
- // the stub is 20-byte size and 4-aligned
- MCE.startFunctionStub(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]
+ // The compilation callback will overwrite the first two words of this
+ // stub with indirect branch instructions targeting the compiled code.
+ // This stub sets the return address to restart the stub, so that
+ // the new branch will be invoked when we come back.
+ //
+ // Branch and link to the compilation callback.
+ // The stub is 16-byte size and 4-byte aligned.
+ JCE.emitAlignment(4);
+ Addr = (void*)JCE.getCurrentPCValue();
+ if (!sys::Memory::setRangeWritable(Addr, 16)) {
+ llvm_unreachable("ERROR: Unable to mark stub writable");
+ }
+ // Save LR so the callback can determine which stub called it.
+ // The compilation callback is responsible for popping this prior
+ // to returning.
+ JCE.emitWordLE(0xe92d4000); // push {lr}
+ // Set the return address to go back to the start of this stub.
+ JCE.emitWordLE(0xe24fe00c); // sub lr, pc, #12
+ // Invoke the compilation callback.
+ JCE.emitWordLE(0xe51ff004); // ldr pc, [pc, #-4]
+ // The address of the compilation callback.
+ JCE.emitWordLE((intptr_t)ARMCompilationCallback);
+ sys::Memory::InvalidateInstructionCache(Addr, 16);
+ if (!sys::Memory::setRangeExecutable(Addr, 16)) {
+ llvm_unreachable("ERROR: Unable to mark stub executable");
+ }
}
- return MCE.finishFunctionStub(0);
+ return Addr;
+}
+
+intptr_t ARMJITInfo::resolveRelocDestAddr(MachineRelocation *MR) const {
+ ARM::RelocationType RT = (ARM::RelocationType)MR->getRelocationType();
+ switch (RT) {
+ default:
+ return (intptr_t)(MR->getResultPointer());
+ case ARM::reloc_arm_pic_jt:
+ // Destination address - jump table base.
+ return (intptr_t)(MR->getResultPointer()) - MR->getConstantVal();
+ case ARM::reloc_arm_jt_base:
+ // Jump table base address.
+ return getJumpTableBaseAddr(MR->getJumpTableIndex());
+ case ARM::reloc_arm_cp_entry:
+ case ARM::reloc_arm_vfp_cp_entry:
+ // Constant pool entry address.
+ return getConstantPoolEntryAddr(MR->getConstantPoolIndex());
+ case ARM::reloc_arm_machine_cp_entry: {
+ ARMConstantPoolValue *ACPV = (ARMConstantPoolValue*)MR->getConstantVal();
+ assert((!ACPV->hasModifier() && !ACPV->mustAddCurrentAddress()) &&
+ "Can't handle this machine constant pool entry yet!");
+ intptr_t Addr = (intptr_t)(MR->getResultPointer());
+ Addr -= getPCLabelAddr(ACPV->getLabelId()) + ACPV->getPCAdjustment();
+ return Addr;
+ }
+ }
}
/// relocate - Before the JIT can run a block of code that has been emitted,
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();
+ intptr_t ResultPtr = resolveRelocDestAddr(MR);
switch ((ARM::RelocationType)MR->getRelocationType()) {
+ case ARM::reloc_arm_cp_entry:
+ case ARM::reloc_arm_vfp_cp_entry:
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;
+ ResultPtr = ResultPtr - (intptr_t)RelocPos - 8;
// If the result is positive, set bit U(23) to 1.
if (ResultPtr >= 0)
- *((unsigned*)RelocPos) |= 1 << 23;
+ *((intptr_t*)RelocPos) |= 1 << ARMII::U_BitShift;
else {
- // otherwise, obtain the absolute value and set
- // bit U(23) to 0.
- ResultPtr *= -1;
- *((unsigned*)RelocPos) &= 0xFF7FFFFF;
+ // Otherwise, obtain the absolute value and set bit U(23) to 0.
+ *((intptr_t*)RelocPos) &= ~(1 << ARMII::U_BitShift);
+ ResultPtr = - ResultPtr;
}
- // set the immed value calculated
- *((unsigned*)RelocPos) |= (unsigned)ResultPtr;
- // set register Rn to PC
- *((unsigned*)RelocPos) |= 0xF << 16;
+ // Set the immed value calculated.
+ // VFP immediate offset is multiplied by 4.
+ if (MR->getRelocationType() == ARM::reloc_arm_vfp_cp_entry)
+ ResultPtr = ResultPtr >> 2;
+ *((intptr_t*)RelocPos) |= ResultPtr;
+ // Set register Rn to PC (which is register 15 on all architectures).
+ // FIXME: This avoids the need for register info in the JIT class.
+ *((intptr_t*)RelocPos) |= 15 << ARMII::RegRnShift;
+ break;
+ }
+ case ARM::reloc_arm_pic_jt:
+ case ARM::reloc_arm_machine_cp_entry:
+ case ARM::reloc_arm_absolute: {
+ // These addresses have already been resolved.
+ *((intptr_t*)RelocPos) |= (intptr_t)ResultPtr;
break;
}
case ARM::reloc_arm_branch: {
// 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 - (intptr_t)RelocPos - 8;
ResultPtr = (ResultPtr & 0x03FFFFFC) >> 2;
assert(ResultPtr >= -33554432 && ResultPtr <= 33554428);
- *((unsigned*)RelocPos) |= ResultPtr;
+ *((intptr_t*)RelocPos) |= ResultPtr;
+ break;
+ }
+ case ARM::reloc_arm_jt_base: {
+ // JT base - (instruction addr + 8)
+ ResultPtr = ResultPtr - (intptr_t)RelocPos - 8;
+ *((intptr_t*)RelocPos) |= ResultPtr;
+ break;
+ }
+ case ARM::reloc_arm_movw: {
+ ResultPtr = ResultPtr & 0xFFFF;
+ *((intptr_t*)RelocPos) |= ResultPtr & 0xFFF;
+ *((intptr_t*)RelocPos) |= ((ResultPtr >> 12) & 0xF) << 16;
+ break;
+ }
+ case ARM::reloc_arm_movt: {
+ ResultPtr = (ResultPtr >> 16) & 0xFFFF;
+ *((intptr_t*)RelocPos) |= ResultPtr & 0xFFF;
+ *((intptr_t*)RelocPos) |= ((ResultPtr >> 12) & 0xF) << 16;
break;
}
}
}
}
+
+void ARMJITInfo::Initialize(const MachineFunction &MF, bool isPIC) {
+ const ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
+ ConstPoolId2AddrMap.resize(AFI->getNumPICLabels());
+ JumpTableId2AddrMap.resize(AFI->getNumJumpTables());
+ IsPIC = isPIC;
+}
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