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	No new test case is added. This patch makes test JITTest.FunctionIsRecompiledAndRelinked pass on mips platform. Patch by Petar Jovanovic. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161098 91177308-0d34-0410-b5e6-96231b3b80d8
		
			
				
	
	
		
			279 lines
		
	
	
		
			9.3 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
			
		
		
	
	
			279 lines
		
	
	
		
			9.3 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
| //===-- MipsJITInfo.cpp - Implement the Mips JIT Interface ----------------===//
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| //
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| //                     The LLVM Compiler Infrastructure
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| //
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| // This file is distributed under the University of Illinois Open Source
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| // License. See LICENSE.TXT for details.
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| //
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| //===----------------------------------------------------------------------===//
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| //
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| // This file implements the JIT interfaces for the Mips target.
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| //
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| //===----------------------------------------------------------------------===//
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| 
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| #define DEBUG_TYPE "jit"
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| #include "MipsJITInfo.h"
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| #include "MipsInstrInfo.h"
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| #include "MipsRelocations.h"
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| #include "MipsSubtarget.h"
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| #include "llvm/Function.h"
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| #include "llvm/CodeGen/JITCodeEmitter.h"
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| #include "llvm/Support/Debug.h"
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| #include "llvm/Support/ErrorHandling.h"
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| #include "llvm/Support/raw_ostream.h"
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| #include "llvm/Support/Memory.h"
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| #include <cstdlib>
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| using namespace llvm;
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| 
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| 
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| void MipsJITInfo::replaceMachineCodeForFunction(void *Old, void *New) {
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|   unsigned NewAddr = (intptr_t)New;
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|   unsigned OldAddr = (intptr_t)Old;
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|   const unsigned NopInstr = 0x0;
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| 
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|   // If the functions are in the same memory segment, insert PC-region branch.
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|   if ((NewAddr & 0xF0000000) == ((OldAddr + 4) & 0xF0000000)) {
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|     unsigned *OldInstruction = (unsigned *)Old;
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|     *OldInstruction = 0x08000000;
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|     unsigned JTargetAddr = NewAddr & 0x0FFFFFFC;
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| 
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|     JTargetAddr >>= 2;
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|     *OldInstruction |= JTargetAddr;
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| 
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|     // Insert a NOP.
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|     OldInstruction++;
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|     *OldInstruction = NopInstr;
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| 
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|     sys::Memory::InvalidateInstructionCache(Old, 2 * 4);
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|   } else {
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|     // We need to clear hint bits from the instruction, in case it is 'jr ra'.
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|     const unsigned HintMask = 0xFFFFF83F, ReturnSequence = 0x03e00008;
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|     unsigned* CurrentInstr = (unsigned*)Old;
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|     unsigned CurrInstrHintClear = (*CurrentInstr) & HintMask;
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|     unsigned* NextInstr = CurrentInstr + 1;
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|     unsigned NextInstrHintClear = (*NextInstr) & HintMask;
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| 
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|     // Do absolute jump if there are 2 or more instructions before return from
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|     // the old function.
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|     if ((CurrInstrHintClear != ReturnSequence) &&
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|         (NextInstrHintClear != ReturnSequence)) {
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|       const unsigned LuiT0Instr = 0x3c080000, AddiuT0Instr = 0x25080000;
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|       const unsigned JrT0Instr = 0x01000008;
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|       // lui  t0,  high 16 bit of the NewAddr
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|       (*(CurrentInstr++)) = LuiT0Instr | ((NewAddr & 0xffff0000) >> 16);
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|       // addiu  t0, t0, low 16 bit of the NewAddr
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|       (*(CurrentInstr++)) = AddiuT0Instr | (NewAddr & 0x0000ffff);
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|       // jr t0
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|       (*(CurrentInstr++)) = JrT0Instr;
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|       (*CurrentInstr) = NopInstr;
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| 
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|       sys::Memory::InvalidateInstructionCache(Old, 4 * 4);
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|     } else {
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|       // Unsupported case
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|       report_fatal_error("MipsJITInfo::replaceMachineCodeForFunction");
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|     }
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|   }
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| }
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| 
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| /// JITCompilerFunction - This contains the address of the JIT function used to
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| /// compile a function lazily.
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| static TargetJITInfo::JITCompilerFn JITCompilerFunction;
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| 
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| // Get the ASMPREFIX for the current host.  This is often '_'.
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| #ifndef __USER_LABEL_PREFIX__
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| #define __USER_LABEL_PREFIX__
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| #endif
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| #define GETASMPREFIX2(X) #X
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| #define GETASMPREFIX(X) GETASMPREFIX2(X)
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| #define ASMPREFIX GETASMPREFIX(__USER_LABEL_PREFIX__)
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| 
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| // CompilationCallback stub - We can't use a C function with inline assembly in
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| // it, because the prolog/epilog inserted by GCC won't work for us. Instead,
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| // write our own wrapper, which does things our way, so we have complete control
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| // over register saving and restoring. This code saves registers, calls
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| // MipsCompilationCallbackC and restores registers.
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| extern "C" {
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| #if defined (__mips__)
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| void MipsCompilationCallback();
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| 
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|   asm(
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|     ".text\n"
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|     ".align 2\n"
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|     ".globl " ASMPREFIX "MipsCompilationCallback\n"
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|     ASMPREFIX "MipsCompilationCallback:\n"
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|     ".ent " ASMPREFIX "MipsCompilationCallback\n"
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|     ".frame  $sp, 32, $ra\n"
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|     ".set  noreorder\n"
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|     ".cpload $t9\n"
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| 
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|     "addiu $sp, $sp, -64\n"
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|     ".cprestore 16\n"
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| 
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|     // Save argument registers a0, a1, a2, a3, f12, f14 since they may contain
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|     // stuff for the real target function right now. We have to act as if this
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|     // whole compilation callback doesn't exist as far as the caller is
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|     // concerned. We also need to save the ra register since it contains the
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|     // original return address, and t8 register since it contains the address
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|     // of the end of function stub.
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|     "sw $a0, 20($sp)\n"
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|     "sw $a1, 24($sp)\n"
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|     "sw $a2, 28($sp)\n"
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|     "sw $a3, 32($sp)\n"
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|     "sw $ra, 36($sp)\n"
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|     "sw $t8, 40($sp)\n"
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|     "sdc1 $f12, 48($sp)\n"
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|     "sdc1 $f14, 56($sp)\n"
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| 
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|     // t8 points at the end of function stub. Pass the beginning of the stub
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|     // to the MipsCompilationCallbackC.
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|     "addiu $a0, $t8, -16\n"
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|     "jal " ASMPREFIX "MipsCompilationCallbackC\n"
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|     "nop\n"
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| 
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|     // Restore registers.
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|     "lw $a0, 20($sp)\n"
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|     "lw $a1, 24($sp)\n"
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|     "lw $a2, 28($sp)\n"
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|     "lw $a3, 32($sp)\n"
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|     "lw $ra, 36($sp)\n"
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|     "lw $t8, 40($sp)\n"
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|     "ldc1 $f12, 48($sp)\n"
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|     "ldc1 $f14, 56($sp)\n"
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|     "addiu $sp, $sp, 64\n"
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| 
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|     // Jump to the (newly modified) stub to invoke the real function.
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|     "addiu $t8, $t8, -16\n"
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|     "jr $t8\n"
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|     "nop\n"
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| 
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|     ".set  reorder\n"
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|     ".end " ASMPREFIX "MipsCompilationCallback\n"
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|       );
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| #else  // host != Mips
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|   void MipsCompilationCallback() {
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|     llvm_unreachable(
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|       "Cannot call MipsCompilationCallback() on a non-Mips arch!");
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|   }
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| #endif
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| }
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| 
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| /// MipsCompilationCallbackC - This is the target-specific function invoked
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| /// by the function stub when we did not know the real target of a call.
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| /// This function must locate the start of the stub or call site and pass
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| /// it into the JIT compiler function.
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| extern "C" void MipsCompilationCallbackC(intptr_t StubAddr) {
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|   // Get the address of the compiled code for this function.
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|   intptr_t NewVal = (intptr_t) JITCompilerFunction((void*) StubAddr);
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| 
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|   // Rewrite the function stub so that we don't end up here every time we
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|   // execute the call. We're replacing the first four instructions of the
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|   // stub with code that jumps to the compiled function:
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|   //   lui $t9, %hi(NewVal)
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|   //   addiu $t9, $t9, %lo(NewVal)
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|   //   jr $t9
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|   //   nop
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| 
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|   int Hi = ((unsigned)NewVal & 0xffff0000) >> 16;
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|   if ((NewVal & 0x8000) != 0)
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|     Hi++;
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|   int Lo = (int)(NewVal & 0xffff);
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| 
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|   *(intptr_t *)(StubAddr) = 0xf << 26 | 25 << 16 | Hi;
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|   *(intptr_t *)(StubAddr + 4) = 9 << 26 | 25 << 21 | 25 << 16 | Lo;
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|   *(intptr_t *)(StubAddr + 8) = 25 << 21 | 8;
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|   *(intptr_t *)(StubAddr + 12) = 0;
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| 
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|   sys::Memory::InvalidateInstructionCache((void*) StubAddr, 16);
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| }
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| 
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| TargetJITInfo::LazyResolverFn MipsJITInfo::getLazyResolverFunction(
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|     JITCompilerFn F) {
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|   JITCompilerFunction = F;
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|   return MipsCompilationCallback;
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| }
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| 
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| TargetJITInfo::StubLayout MipsJITInfo::getStubLayout() {
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|   // The stub contains 4 4-byte instructions, aligned at 4 bytes. See
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|   // emitFunctionStub for details.
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|   StubLayout Result = { 4*4, 4 };
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|   return Result;
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| }
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| 
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| void *MipsJITInfo::emitFunctionStub(const Function *F, void *Fn,
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|                                     JITCodeEmitter &JCE) {
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|   JCE.emitAlignment(4);
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|   void *Addr = (void*) (JCE.getCurrentPCValue());
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|   if (!sys::Memory::setRangeWritable(Addr, 16))
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|     llvm_unreachable("ERROR: Unable to mark stub writable.");
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| 
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|   intptr_t EmittedAddr;
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|   if (Fn != (void*)(intptr_t)MipsCompilationCallback)
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|     EmittedAddr = (intptr_t)Fn;
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|   else
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|     EmittedAddr = (intptr_t)MipsCompilationCallback;
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| 
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| 
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|   int Hi = ((unsigned)EmittedAddr & 0xffff0000) >> 16;
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|   if ((EmittedAddr & 0x8000) != 0)
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|     Hi++;
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|   int Lo = (int)(EmittedAddr & 0xffff);
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| 
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|   // lui t9, %hi(EmittedAddr)
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|   // addiu t9, t9, %lo(EmittedAddr)
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|   // jalr t8, t9
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|   // nop
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|   JCE.emitWordLE(0xf << 26 | 25 << 16 | Hi);
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|   JCE.emitWordLE(9 << 26 | 25 << 21 | 25 << 16 | Lo);
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|   JCE.emitWordLE(25 << 21 | 24 << 11 | 9);
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|   JCE.emitWordLE(0);
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| 
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|   sys::Memory::InvalidateInstructionCache(Addr, 16);
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|   if (!sys::Memory::setRangeExecutable(Addr, 16))
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|     llvm_unreachable("ERROR: Unable to mark stub executable.");
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| 
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|   return Addr;
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| }
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| 
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| /// relocate - Before the JIT can run a block of code that has been emitted,
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| /// it must rewrite the code to contain the actual addresses of any
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| /// referenced global symbols.
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| void MipsJITInfo::relocate(void *Function, MachineRelocation *MR,
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|                            unsigned NumRelocs, unsigned char *GOTBase) {
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|   for (unsigned i = 0; i != NumRelocs; ++i, ++MR) {
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| 
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|     void *RelocPos = (char*) Function + MR->getMachineCodeOffset();
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|     intptr_t ResultPtr = (intptr_t) MR->getResultPointer();
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| 
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|     switch ((Mips::RelocationType) MR->getRelocationType()) {
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|     case Mips::reloc_mips_pc16:
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|       ResultPtr = (((ResultPtr - (intptr_t) RelocPos) - 4) >> 2) & 0xffff;
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|       *((unsigned*) RelocPos) |= (unsigned) ResultPtr;
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|       break;
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| 
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|     case Mips::reloc_mips_26:
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|       ResultPtr = (ResultPtr & 0x0fffffff) >> 2;
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|       *((unsigned*) RelocPos) |= (unsigned) ResultPtr;
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|       break;
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| 
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|     case Mips::reloc_mips_hi:
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|       ResultPtr = ResultPtr >> 16;
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|       if ((((intptr_t) (MR->getResultPointer()) & 0xffff) >> 15) == 1) {
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|         ResultPtr += 1;
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|       }
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|       *((unsigned*) RelocPos) |= (unsigned) ResultPtr;
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|       break;
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| 
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|     case Mips::reloc_mips_lo: {
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|       // Addend is needed for unaligned load/store instructions, where offset
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|       // for the second load/store in the expanded instruction sequence must
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|       // be modified by +1 or +3. Otherwise, Addend is 0.
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|       int Addend = *((unsigned*) RelocPos) & 0xffff;
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|       ResultPtr = (ResultPtr + Addend) & 0xffff;
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|       *((unsigned*) RelocPos) &= 0xffff0000;
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|       *((unsigned*) RelocPos) |= (unsigned) ResultPtr;
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|       break;
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|     }
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|     }
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|   }
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| }
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