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<div>Hi,</div>
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<div>Can anyone help me to fill in the missing details here please? I'm sure this is a very short piece of code, but I can't find the right way of doing this...</div>
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<div><span style="font-size: 10pt;"><font face="Courier New">MachineBasicBlock* SparcTargetLowering::</font></span></div>
<div><font face="Courier New">emitEHSjLjLongJmp(MachineInstr *MI,</font></div>
<div><font face="Courier New"> MachineBasicBlock *MBB) const</font></div>
<div><font face="Courier New">{</font></div>
<div><font face="Courier New"> [... Code omitted for brevity]</font></div>
<div><font face="Courier New"> </font></div>
<div><font face="Courier New"> MVT PVT = getPointerTy(MF->getDataLayout());</font></div>
<div><font face="Courier New"> unsigned PtrSize = PVT.getStoreSize();</font></div>
<div><font face="Courier New"> // We'll deal with 64 bit implementations when the 32 bit version is working!</font></div>
<div><font face="Courier New"> assert(PVT == MVT::i32 && "Invalid Pointer Size!");</font></div>
<div><font face="Courier New"> </font></div>
<div><font face="Courier New"> MachineBasicBlock *jumpToMBB = MF->CreateMachineBasicBlock(BB);</font></div>
<div><font face="Courier New"> MF->insert(I, mainMBB);</font></div>
<div><font face="Courier New"><br>
</font></div>
<div><font face="Courier New"> const TargetRegisterClass *PtrRC = getRegClassFor(PVT);</font></div>
<div><font face="Courier New"> unsigned LabelReg = MRI.createVirtualRegister(PtrRC);</font></div>
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</font></div>
<div><font face="Courier New"> // Need to load the address of "jumpToMBB" into register "LabelReg", so that</font></div>
<div><font face="Courier New"> // we can then (later) store this in a buffer, to be recovered by "longjmp" as</font></div>
<div><font face="Courier New"> // the location to resume execution at (via a JMPL instruction).</font></div>
<div><font face="Courier New"> </font></div>
<div><font face="Courier New"> // We need something like this, garnered from the PPC implementation.</font></div>
<div><font face="Courier New"> // What is the equivalent code in Sparc utilizing the instructions SETHI and OR?</font></div>
<div><font face="Courier New"> MIB = BuildMI(mainMBB, DL,</font></div>
<div><font face="Courier New"> TII->get(Subtarget.isPPC64() ? PPC::MFLR8 : PPC::MFLR), LabelReg);</font></div>
<div><font face="Courier New"><span class="Apple-tab-span" style="white-space:pre"></span> </font></div>
<div><font face="Courier New"> // ...or possibly, it should be something like this, using addMBB (I know this isn't legal, BTW)</font></div>
<div><font face="Courier New"> MIB = BuildMI(mainMBB, DL,</font></div>
<div><font face="Courier New"> TII->get(SP::LDri, LabelReg).addMBB(jumpToMBB);</font></div>
<div><font face="Courier New"> </font></div>
<div><font face="Courier New"> [... Code omitted for brevity]</font></div>
<div><font face="Courier New">}</font></div>
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<div id="divRpF314299" style="font-family: 'Times New Roman'; direction: ltr;"><font face="Tahoma" size="2" color="#000000"><b>From:</b> Chris.Dewhurst<br>
<b>Sent:</b> 15 April 2016 18:17<br>
<b>To:</b> llvm-dev@lists.llvm.org<br>
<b>Subject:</b> Re: [llvm-dev] [Sparc] Load address with SETHI<br>
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<div style="direction:ltr; font-family:Tahoma; color:#000000; font-size:10pt"><span style="font-family:'Segoe UI',Helvetica,Arial,sans-serif; font-size:13.3333px">> > Some more information on what I have so far. I'll actually focus on the longjmp side, as the
problem is probably easier.</span><br style="font-family:'Segoe UI',Helvetica,Arial,sans-serif; font-size:13.3333px">
<span style="font-family:'Segoe UI',Helvetica,Arial,sans-serif; font-size:13.3333px">> > </span><br style="font-family:'Segoe UI',Helvetica,Arial,sans-serif; font-size:13.3333px">
<span style="font-family:'Segoe UI',Helvetica,Arial,sans-serif; font-size:13.3333px">> > I need to get the SETHI / OR combination inserted where the comment</span><br style="font-family:'Segoe UI',Helvetica,Arial,sans-serif; font-size:13.3333px">
<span style="font-family:'Segoe UI',Helvetica,Arial,sans-serif; font-size:13.3333px">> > "*** Need to use the SETHI / OR combination here. ***" appears in the</span><br style="font-family:'Segoe UI',Helvetica,Arial,sans-serif; font-size:13.3333px">
<span style="font-family:'Segoe UI',Helvetica,Arial,sans-serif; font-size:13.3333px">> > code below, but I'm not sure that this is done anywhere near this piece</span><br style="font-family:'Segoe UI',Helvetica,Arial,sans-serif; font-size:13.3333px">
<span style="font-family:'Segoe UI',Helvetica,Arial,sans-serif; font-size:13.3333px">> > of code, so I'll include all the relevant parts that I can find of my</span><br style="font-family:'Segoe UI',Helvetica,Arial,sans-serif; font-size:13.3333px">
<span style="font-family:'Segoe UI',Helvetica,Arial,sans-serif; font-size:13.3333px">> > current implementation.</span><br style="font-family:'Segoe UI',Helvetica,Arial,sans-serif; font-size:13.3333px">
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<span style="font-family:'Segoe UI',Helvetica,Arial,sans-serif; font-size:13.3333px">> I don't understand what exactly you want to materialize here. Shouldn't</span><br style="font-family:'Segoe UI',Helvetica,Arial,sans-serif; font-size:13.3333px">
<span style="font-family:'Segoe UI',Helvetica,Arial,sans-serif; font-size:13.3333px">> the address of the buffer already be an operand at this point?</span><br style="font-family:'Segoe UI',Helvetica,Arial,sans-serif; font-size:13.3333px">
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<span style="font-family:'Segoe UI',Helvetica,Arial,sans-serif; font-size:13.3333px">> Joerg</span><br style="font-family:'Segoe UI',Helvetica,Arial,sans-serif; font-size:13.3333px">
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<div>Quite possibly, I've over-simplified my example. Perhaps I should have focussed more on the setjmp part, which is actually where I was coding anyway. In this, I need to store the address of the instruction after I've lowered the intrinsic into a buffer
so that I can recover this and jump back to it from the longjmp intrinsic.</div>
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<div>There are two or three parts, and I'm not sure how to go about either. After I get these working, the rest is (I think) plain-sailing:</div>
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<div>(1) I need to take the address of the instruction after the lowered setjmp intrinsic, which I think requires that I create a new basic block</div>
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<div>(2) I need to get the address of this basic block, at lowering time, and get it into a register using the SETHI / OR combination (I presume). Once it's in the register, I can store it in the buffer easily. There must surely be a good way to load an address
using SETHI / OR, but nothing I've tried (including "makeAddress") works so far. I guess I could code each of SETHI and OR individually, but surely there's some code around to take care of this already.</div>
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<div>(3) Is there anything else? Do I need any indicators to let the back-end know it'll need to fix-up the address taken in step (2) later in the compilation - or possibly in the link - pipeline?</div>
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