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fe25521451
To support compressing the debug_line section that contains multiple fragments (due, I believe, to variation in choices of line table encoding depending on the size of instruction ranges in the actual program code) we needed to support compressing multiple MCFragments in a single pass. This patch implements that behavior by mutating the post-relaxed and relocated section to be the compressed form of its former self, including renaming the section. This is a more flexible (and less invasive, to a degree) implementation that will allow for other features such as "use compression only if it's smaller than the uncompressed data". Compressing debug_frame would be a possible further extension to this work, but I've left it for now. The hurdle there is alignment sections - which might require going as far as to refactor MCAssembler.cpp:writeFragment to handle writing to a byte buffer or an MCObjectWriter (there's already a virtual call there, so it shouldn't add substantial compile-time cost) which could in turn involve refactoring MCAsmBackend::writeNopData to use that same abstraction... which involves touching all the backends. This would remove the limited handling of fragment writing seen in ELFObjectWriter.cpp:getUncompressedData which would be nice - but it's more invasive. I did discover that I (perhaps obviously) don't need to handle relocations when I rewrite the fragments - since the relocations have already been applied and computed (and stored into ELFObjectWriter::Relocations) by this stage (necessarily, because we need to have written any immediate values or assembly-time relocations into the data already before we compress it, which we have). The test case doesn't necessarily cover that in detail - I can add more test coverage if that's preferred. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205990 91177308-0d34-0410-b5e6-96231b3b80d8 |
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Analysis | ||
Assembler | ||
Bindings | ||
Bitcode | ||
BugPoint | ||
CodeGen | ||
DebugInfo | ||
ExecutionEngine | ||
Feature | ||
FileCheck | ||
Instrumentation | ||
Integer | ||
JitListener | ||
Linker | ||
LTO | ||
MC | ||
Object | ||
Other | ||
TableGen | ||
tools | ||
Transforms | ||
Unit | ||
Verifier | ||
YAMLParser | ||
.clang-format | ||
CMakeLists.txt | ||
lit.cfg | ||
lit.site.cfg.in | ||
Makefile | ||
Makefile.tests | ||
TestRunner.sh |