public InstructionOffsetMap(@Nonnull List<? extends Instruction> instructions) {
        this.instructionCodeOffsets = new int[instructions.size()];

        int codeOffset = 0;
        for (int i=0; i<instructions.size(); i++) {
            instructionCodeOffsets[i] = codeOffset;
            codeOffset += instructions.get(i).getCodeUnits();
        }
    }
@Test
    public void testInstructionOffsetMap() {
        ImmutableList<ImmutableInstruction> instructions = ImmutableList.of(
                /*00: 0x00*/ new ImmutableInstruction10t(Opcode.GOTO, 1),
                /*01: 0x01*/ new ImmutableInstruction10x(Opcode.NOP),
                /*02: 0x02*/ new ImmutableInstruction11n(Opcode.CONST_4, 2, 3),
                /*03: 0x03*/ new ImmutableInstruction11x(Opcode.RETURN, 4),
                /*04: 0x04*/ new ImmutableInstruction12x(Opcode.ARRAY_LENGTH, 5, 6),
                /*05: 0x05*/ new ImmutableInstruction20t(Opcode.GOTO_16, 7),
                /*06: 0x07*/ new ImmutableInstruction21c(Opcode.CONST_STRING, 8, new ImmutableStringReference("blah")),
                /*07: 0x09*/ new ImmutableInstruction21ih(Opcode.CONST_HIGH16, 9, 0x10000),
                /*08: 0x0b*/ new ImmutableInstruction21lh(Opcode.CONST_WIDE_HIGH16, 10, 0x1000000000000L),
                /*09: 0x0d*/ new ImmutableInstruction21s(Opcode.CONST_16, 11, 12),
                /*10: 0x0f*/ new ImmutableInstruction21t(Opcode.IF_EQZ, 12, 13),
                /*11: 0x11*/ new ImmutableInstruction22b(Opcode.ADD_INT_LIT8, 14, 15, 16),
                /*12: 0x13*/ new ImmutableInstruction22c(Opcode.INSTANCE_OF, 0, 1,
                                                         new ImmutableTypeReference("Ltype;")),
                /*13: 0x15*/ new ImmutableInstruction22s(Opcode.ADD_INT_LIT16, 2, 3, 17),
                /*14: 0x17*/ new ImmutableInstruction22t(Opcode.IF_EQ, 4, 5, 18),
                /*15: 0x19*/ new ImmutableInstruction22x(Opcode.MOVE_FROM16, 19, 20),
                /*16: 0x1b*/ new ImmutableInstruction23x(Opcode.AGET, 21, 22, 23),
                /*17: 0x1d*/ new ImmutableInstruction30t(Opcode.GOTO_32, 24),
                /*18: 0x20*/ new ImmutableInstruction31c(Opcode.CONST_STRING_JUMBO, 25,
                                                         new ImmutableStringReference("this is a string")),
                /*19: 0x23*/ new ImmutableInstruction31i(Opcode.CONST, 26, 27),
                /*20: 0x26*/ new ImmutableInstruction31t(Opcode.FILL_ARRAY_DATA, 28, 29),
                /*21: 0x29*/ new ImmutableInstruction32x(Opcode.MOVE_16, 30, 31),
                /*22: 0x2c*/ new ImmutableInstruction35c(Opcode.FILLED_NEW_ARRAY, 0, 0, 0, 0, 0, 0,
                                                         new ImmutableTypeReference("Ltype;")),
                /*23: 0x2f*/ new ImmutableInstruction3rc(Opcode.FILLED_NEW_ARRAY_RANGE, 0, 0,
                                                         new ImmutableTypeReference("Ltype;")),
                /*24: 0x32*/ new ImmutableInstruction51l(Opcode.CONST_WIDE, 32, 33),
                /*25: 0x37*/ new ImmutableInstruction10t(Opcode.GOTO, 1)
        );
        ImmutableMethodImplementation impl = new ImmutableMethodImplementation(33, instructions, null, null);
        InstructionOffsetMap instructionOffsetMap = new InstructionOffsetMap(instructions);

        int[] expectedOffsets = new int[] { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x07, 0x09, 0x0b, 0x0d, 0x0f, 0x11,
                0x13, 0x15, 0x17, 0x19, 0x1b, 0x1d, 0x20, 0x23, 0x26, 0x29, 0x2c, 0x2f, 0x32, 0x37};

        for (int i=0; i<instructions.size(); i++) {
            Assert.assertEquals(expectedOffsets[i], instructionOffsetMap.getInstructionCodeOffset(i));
            Assert.assertEquals(i, instructionOffsetMap.getInstructionIndexAtCodeOffset(expectedOffsets[i], true));
            Assert.assertEquals(i, instructionOffsetMap.getInstructionIndexAtCodeOffset(expectedOffsets[i], false));
        }

        int instructionIndex = -1;
        for (int codeOffset=0; codeOffset<=expectedOffsets[expectedOffsets.length-1]; codeOffset++) {
            if (codeOffset == expectedOffsets[instructionIndex+1]) {
                // this offset is at the beginning of an instruction
                instructionIndex++;
            } else {
                // this offset is in the middle of an instruction
                Assert.assertEquals(instructionIndex,
                        instructionOffsetMap.getInstructionIndexAtCodeOffset(codeOffset, false));

                try {
                    instructionOffsetMap.getInstructionIndexAtCodeOffset(codeOffset, true);
                    Assert.fail(String.format("Exception exception didn't occur for code offset 0x%x", codeOffset));
                } catch (ExceptionWithContext ex) {
                    // expected exception
                }
            }
        }
        Assert.assertEquals(expectedOffsets.length-1,
                instructionOffsetMap.getInstructionIndexAtCodeOffset(expectedOffsets[expectedOffsets.length-1]+1, false));
        Assert.assertEquals(expectedOffsets.length-1,
                instructionOffsetMap.getInstructionIndexAtCodeOffset(expectedOffsets[expectedOffsets.length-1]+10, false));
    }