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0a67d92938
Major cleanup of whitespace and formatting issues in MBlaze backend git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@118434 91177308-0d34-0410-b5e6-96231b3b80d8
40 lines
2.2 KiB
Plaintext
40 lines
2.2 KiB
Plaintext
* Writing out ELF files is close to working but the following needs to
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be examined more closely:
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- ELF relocation records are incorrect because the function
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ELFObjectWriter::RecordRelocation is hard coded for X86/X86-64.
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- Relocations use 2-byte / 4-byte to terminology in reference to
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the size of the immediate value being changed. The Xilinx
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terminology seems to be (???) 4-byte / 8-byte in reference
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to the number of bytes of instructions that are being changed.
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- BRLID and like instructions are always assumed to use a 4-byte
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immediate value for the relocation and BEQID and like instructions
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are always assumed to use a 2-byte immediate value for the relocation.
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I think this means that conditional branches like BEQID can only
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branch += 32768 bytes (~8192 instructions). We should allow conditional
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branches to use 4-byte relocations but I'm not sure how to do that
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right now.
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- Relocation records for indirect calls are not being generated
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correctly. These should emit and IMM 0 directly before the ORI
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instruction that loads the register (just like when a BRLID
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instruction is used instead of an ORI).
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* Code generation seems to work relatively well now but the following
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needs to be examined more closely:
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- The stack layout needs to be examined to make sure it meets
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the standard, especially in regards to var arg functions.
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- The delay slot filler is ad hoc but seems to work. Load and
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store instructions were prevented from being moved to delay
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slots but I'm not sure that is necessary.
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- The processor itineraries are copied from a different backend
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and need to be updated to model the MicroBlaze correctly.
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- Look at the MBlazeGenFastISel.inc stuff and make use of it
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if appropriate.
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* A basic assembly parser is present now and seems to parse most things.
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There are a few things that need to be looked at:
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- There are some instructions that are not generated by the backend
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and have not been tested as far as the parser is concerned.
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- The assembly parser does not use any MicroBlaze specific directives.
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I should investigate if there are MicroBlaze specific directive and,
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if there are, add them.
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