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llvm-project/llvm/test/MC/ELF/compression.s

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Recommit 270977 - [llvm-mc] - Teach llvm-mc to generate zlib styled compression sections. Fix: updated clang code which was not updated by mistake. Original commit message: [llvm-mc] - Teach llvm-mc to generate zlib styled compression sections. This patch is strongly based on previously reverted D20331. (because of gnuutils < 2.26 does not support compressed debug sections in non zlib-gnu style) Difference that this patch supports both zlib and zlib-gnu styles. -compress-debug-sections option now supports next values: -compress-debug-sections=zlib-gnu -compress-debug-sections=zlib -compress-debug-sections=none Previously specifying -compress-debug-sections enabled zlib-gnu compression, so anyone can put "-compress-debug-sections=zlib-gnu" to restore the behavior that was before this patch for case when compression was enabled. Differential revision: http://reviews.llvm.org/D20676 llvm-svn: 270987
2016-05-27 20:27:32 +08:00
// Check zlib-gnu style
// RUN: llvm-mc -filetype=obj -compress-debug-sections=zlib-gnu -triple x86_64-pc-linux-gnu < %s -o %t
// RUN: llvm-objdump -s %t | FileCheck --check-prefix=CHECK-GNU-STYLE %s
[MC/ELF] - Fixed insufficient compression.s test Main problem that .debug_info section was used to check that llvm-dwarfdump is able to decompress data that was compressed with llvm-mc tool. This section was not compressed actually, because consumes more space in compressed view. I changed testcase to use .debug_str section which is one that is really compressed. So currently test do what is probably was expected to do: checks that "data"->llvm-mc->llvm-dwarfdump->dumps back initial "data". Differential revision: http://reviews.llvm.org/D20466 llvm-svn: 270560
2016-05-24 21:45:29 +08:00
// RUN: llvm-dwarfdump -debug-dump=str %t | FileCheck --check-prefix=STR %s
Recommit 270977 - [llvm-mc] - Teach llvm-mc to generate zlib styled compression sections. Fix: updated clang code which was not updated by mistake. Original commit message: [llvm-mc] - Teach llvm-mc to generate zlib styled compression sections. This patch is strongly based on previously reverted D20331. (because of gnuutils < 2.26 does not support compressed debug sections in non zlib-gnu style) Difference that this patch supports both zlib and zlib-gnu styles. -compress-debug-sections option now supports next values: -compress-debug-sections=zlib-gnu -compress-debug-sections=zlib -compress-debug-sections=none Previously specifying -compress-debug-sections enabled zlib-gnu compression, so anyone can put "-compress-debug-sections=zlib-gnu" to restore the behavior that was before this patch for case when compression was enabled. Differential revision: http://reviews.llvm.org/D20676 llvm-svn: 270987
2016-05-27 20:27:32 +08:00
// RUN: llvm-mc -filetype=obj -compress-debug-sections=zlib-gnu -triple i386-pc-linux-gnu < %s \
// RUN: | llvm-readobj -symbols - | FileCheck --check-prefix=386-SYMBOLS-GNU %s
// Check zlib style
// RUN: llvm-mc -filetype=obj -compress-debug-sections=zlib -triple x86_64-pc-linux-gnu < %s -o %t
// RUN: llvm-objdump -s %t | FileCheck --check-prefix=CHECK-ZLIB-STYLE %s
// RUN: llvm-dwarfdump -debug-dump=str %t | FileCheck --check-prefix=STR %s
// RUN: llvm-mc -filetype=obj -compress-debug-sections=zlib -triple i386-pc-linux-gnu < %s \
// RUN: | llvm-readobj -symbols - | FileCheck --check-prefix=386-SYMBOLS-ZLIB %s
// RUN: llvm-readobj -sections %t | FileCheck --check-prefix=ZLIB-STYLE-FLAGS %s
Revert debug info compression support. To support compression for debug_line and debug_frame a different approach is required. To simplify review, revert the old implementation and XFAIL the test case. New implementation to follow shortly. Reverts r205059 and r204958. llvm-svn: 205989
2014-04-11 05:53:47 +08:00
Only test compression when linked with zlib. I'll implement error handling and a negative test in both llvm-mc and Clang soon. llvm-svn: 205016
2014-03-29 01:04:53 +08:00
// REQUIRES: zlib
Compress debug sections only when beneficial. Both ZLIB and the debug info compressed section header ("ZLIB" + the size of the uncompressed data) take some constant overhead so in some cases the compressed data is actually larger than the uncompressed data. In these cases, just don't compress or rename the section at all. llvm-svn: 206659
2014-04-19 05:52:26 +08:00
// Don't compress small sections, such as this simple debug_abbrev example
Recommit 270977 - [llvm-mc] - Teach llvm-mc to generate zlib styled compression sections. Fix: updated clang code which was not updated by mistake. Original commit message: [llvm-mc] - Teach llvm-mc to generate zlib styled compression sections. This patch is strongly based on previously reverted D20331. (because of gnuutils < 2.26 does not support compressed debug sections in non zlib-gnu style) Difference that this patch supports both zlib and zlib-gnu styles. -compress-debug-sections option now supports next values: -compress-debug-sections=zlib-gnu -compress-debug-sections=zlib -compress-debug-sections=none Previously specifying -compress-debug-sections enabled zlib-gnu compression, so anyone can put "-compress-debug-sections=zlib-gnu" to restore the behavior that was before this patch for case when compression was enabled. Differential revision: http://reviews.llvm.org/D20676 llvm-svn: 270987
2016-05-27 20:27:32 +08:00
// CHECK-GNU-STYLE: Contents of section .debug_abbrev:
// CHECK-GNU-STYLE-NOT: ZLIB
// CHECK-GNU-STYLE-NOT: Contents of
Compress debug sections only when beneficial. Both ZLIB and the debug info compressed section header ("ZLIB" + the size of the uncompressed data) take some constant overhead so in some cases the compressed data is actually larger than the uncompressed data. In these cases, just don't compress or rename the section at all. llvm-svn: 206659
2014-04-19 05:52:26 +08:00
Recommit 270977 - [llvm-mc] - Teach llvm-mc to generate zlib styled compression sections. Fix: updated clang code which was not updated by mistake. Original commit message: [llvm-mc] - Teach llvm-mc to generate zlib styled compression sections. This patch is strongly based on previously reverted D20331. (because of gnuutils < 2.26 does not support compressed debug sections in non zlib-gnu style) Difference that this patch supports both zlib and zlib-gnu styles. -compress-debug-sections option now supports next values: -compress-debug-sections=zlib-gnu -compress-debug-sections=zlib -compress-debug-sections=none Previously specifying -compress-debug-sections enabled zlib-gnu compression, so anyone can put "-compress-debug-sections=zlib-gnu" to restore the behavior that was before this patch for case when compression was enabled. Differential revision: http://reviews.llvm.org/D20676 llvm-svn: 270987
2016-05-27 20:27:32 +08:00
// CHECK-GNU-STYLE: Contents of section .debug_info:
Debug Compression: Avoid compression debug_frame for now Turns out debug_frame does use multiple fragments, so it doesn't compress correctly with the current approach. Disable compressing it for now while I figure out what's the best solution for it. llvm-svn: 205059
2014-03-29 05:48:31 +08:00
Recommit 270977 - [llvm-mc] - Teach llvm-mc to generate zlib styled compression sections. Fix: updated clang code which was not updated by mistake. Original commit message: [llvm-mc] - Teach llvm-mc to generate zlib styled compression sections. This patch is strongly based on previously reverted D20331. (because of gnuutils < 2.26 does not support compressed debug sections in non zlib-gnu style) Difference that this patch supports both zlib and zlib-gnu styles. -compress-debug-sections option now supports next values: -compress-debug-sections=zlib-gnu -compress-debug-sections=zlib -compress-debug-sections=none Previously specifying -compress-debug-sections enabled zlib-gnu compression, so anyone can put "-compress-debug-sections=zlib-gnu" to restore the behavior that was before this patch for case when compression was enabled. Differential revision: http://reviews.llvm.org/D20676 llvm-svn: 270987
2016-05-27 20:27:32 +08:00
// CHECK-GNU-STYLE: Contents of section .zdebug_str:
Revert r270569 (teach llvm-mc to generate compressed debug sections in zlib style). It appears that current ELF linkers are not ready for this. llvm-svn: 270638
2016-05-25 08:14:12 +08:00
// Check for the 'ZLIB' file magic at the start of the section only
Recommit 270977 - [llvm-mc] - Teach llvm-mc to generate zlib styled compression sections. Fix: updated clang code which was not updated by mistake. Original commit message: [llvm-mc] - Teach llvm-mc to generate zlib styled compression sections. This patch is strongly based on previously reverted D20331. (because of gnuutils < 2.26 does not support compressed debug sections in non zlib-gnu style) Difference that this patch supports both zlib and zlib-gnu styles. -compress-debug-sections option now supports next values: -compress-debug-sections=zlib-gnu -compress-debug-sections=zlib -compress-debug-sections=none Previously specifying -compress-debug-sections enabled zlib-gnu compression, so anyone can put "-compress-debug-sections=zlib-gnu" to restore the behavior that was before this patch for case when compression was enabled. Differential revision: http://reviews.llvm.org/D20676 llvm-svn: 270987
2016-05-27 20:27:32 +08:00
// CHECK-GNU-STYLE-NEXT: ZLIB
// CHECK-GNU-STYLE-NOT: ZLIB
Reimplement debug info compression by compressing the whole section, rather than a fragment. 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. llvm-svn: 205990
2014-04-11 05:53:53 +08:00
// FIXME: Handle compressing alignment fragments to support compressing debug_frame
Recommit 270977 - [llvm-mc] - Teach llvm-mc to generate zlib styled compression sections. Fix: updated clang code which was not updated by mistake. Original commit message: [llvm-mc] - Teach llvm-mc to generate zlib styled compression sections. This patch is strongly based on previously reverted D20331. (because of gnuutils < 2.26 does not support compressed debug sections in non zlib-gnu style) Difference that this patch supports both zlib and zlib-gnu styles. -compress-debug-sections option now supports next values: -compress-debug-sections=zlib-gnu -compress-debug-sections=zlib -compress-debug-sections=none Previously specifying -compress-debug-sections enabled zlib-gnu compression, so anyone can put "-compress-debug-sections=zlib-gnu" to restore the behavior that was before this patch for case when compression was enabled. Differential revision: http://reviews.llvm.org/D20676 llvm-svn: 270987
2016-05-27 20:27:32 +08:00
// CHECK-GNU-STYLE: Contents of section .debug_frame:
// CHECK-GNU-STYLE-NOT: ZLIB
// CHECK-GNU-STYLE: Contents of
Reimplement debug info compression by compressing the whole section, rather than a fragment. 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. llvm-svn: 205990
2014-04-11 05:53:53 +08:00
[MC/ELF] - Fixed insufficient compression.s test Main problem that .debug_info section was used to check that llvm-dwarfdump is able to decompress data that was compressed with llvm-mc tool. This section was not compressed actually, because consumes more space in compressed view. I changed testcase to use .debug_str section which is one that is really compressed. So currently test do what is probably was expected to do: checks that "data"->llvm-mc->llvm-dwarfdump->dumps back initial "data". Differential revision: http://reviews.llvm.org/D20466 llvm-svn: 270560
2016-05-24 21:45:29 +08:00
// Decompress one valid dwarf section just to check that this roundtrips,
// we use .zdebug_str section for that
// STR: perfectly compressable data sample *****************************************
DebugInfo: Support for compressed debug info sections 1) When creating a .debug_* section and instead create a .zdebug_ section. 2) When creating a fragment in a .zdebug_* section, make it a compressed fragment. 3) When computing the size of a compressed section, compress the data and use the size of the compressed data. 4) Emit the compressed bytes. Also, check that only if a section has a compressed fragment, then that is the only fragment in the section. Assert-fail if the fragment's data is modified after it is compressed. Initial review on llvm-commits by Eric Christopher and Rafael Espindola. llvm-svn: 204958
2014-03-28 04:45:58 +08:00
Update the fragments of symbols in compressed sections. While unnamed relocations are already cached in side tables in ELFObjectWriter::RecordRelocation, symbols still need their fragments updated to refer to the newly compressed fragment (even if that fragment isn't big enough to fit the offset). Even though we only create temporary symbols in debug info sections this comes up in 32 bit builds where even temporary symbols in mergeable sections (such as debug_str) have to be emitted as named symbols. I tried a few other ways to do this but they all didn't work for various reasons: 1) Canonicalize the MCSymbolData in RecordRelocation, nulling out the Fragment (so it didn't have to be updated by CompressDebugSection). This doesn't work because some code relies on symbols having fragments to indicate that they're defined, I think. 2) Canonicalize the MCSymbolData in RecordRelocation to be "first fragment + absolute offset" so it would be cheaper to just test and update the fragment in CompressDebugSections. This doesn't work because the offset computed in RecordRelocation isn't that of the symbol's fragment, it's the passed in fragment (I haven't figured out what that fragment is - perhaps it's the location where the relocation is to be written). And if the fragment offset has to be computed only for this use we might as well just do it when we need to, in CompressDebugSection. I also added an assert to help catch this a bit more clearly, even though it is UB. The test case improvements would either assert fail and/or valgrind vail without the fix, even if they wouldn't necessarily fail the FileCheck output. llvm-svn: 206653
2014-04-19 05:24:12 +08:00
// In x86 32 bit named symbols are used for temporary symbols in merge
// sections, so make sure we handle symbols inside compressed sections
Recommit 270977 - [llvm-mc] - Teach llvm-mc to generate zlib styled compression sections. Fix: updated clang code which was not updated by mistake. Original commit message: [llvm-mc] - Teach llvm-mc to generate zlib styled compression sections. This patch is strongly based on previously reverted D20331. (because of gnuutils < 2.26 does not support compressed debug sections in non zlib-gnu style) Difference that this patch supports both zlib and zlib-gnu styles. -compress-debug-sections option now supports next values: -compress-debug-sections=zlib-gnu -compress-debug-sections=zlib -compress-debug-sections=none Previously specifying -compress-debug-sections enabled zlib-gnu compression, so anyone can put "-compress-debug-sections=zlib-gnu" to restore the behavior that was before this patch for case when compression was enabled. Differential revision: http://reviews.llvm.org/D20676 llvm-svn: 270987
2016-05-27 20:27:32 +08:00
// 386-SYMBOLS-GNU: Name: .Linfo_string0
// 386-SYMBOLS-GNU-NOT: }
// 386-SYMBOLS-GNU: Section: .zdebug_str
// Now check the zlib style output:
// Don't compress small sections, such as this simple debug_abbrev example
// CHECK-ZLIB-STYLE: Contents of section .debug_abbrev:
// CHECK-ZLIB-STYLE-NOT: ZLIB
// CHECK-ZLIB-STYLE-NOT: Contents of
// CHECK-ZLIB-STYLE: Contents of section .debug_info:
// FIXME: Handle compressing alignment fragments to support compressing debug_frame
// CHECK-ZLIB-STYLE: Contents of section .debug_frame:
// CHECK-ZLIB-STYLE-NOT: ZLIB
// CHECK-ZLIB-STYLE: Contents of
// Check that debug_line section was not renamed, so it is
// zlib-style, not zlib-gnu one. Check that SHF_COMPRESSED was set.
// ZLIB-STYLE-FLAGS: Section {
// ZLIB-STYLE-FLAGS: Index:
// ZLIB-STYLE-FLAGS: Name: .debug_str
// ZLIB-STYLE-FLAGS-NEXT: Type: SHT_PROGBITS
// ZLIB-STYLE-FLAGS-NEXT: Flags [
// ZLIB-STYLE-FLAGS-NEXT: SHF_COMPRESSED
// 386-SYMBOLS-ZLIB: Name: .Linfo_string0
// 386-SYMBOLS-ZLIB-NOT: }
// 386-SYMBOLS-ZLIB: Section: .debug_str
Update the fragments of symbols in compressed sections. While unnamed relocations are already cached in side tables in ELFObjectWriter::RecordRelocation, symbols still need their fragments updated to refer to the newly compressed fragment (even if that fragment isn't big enough to fit the offset). Even though we only create temporary symbols in debug info sections this comes up in 32 bit builds where even temporary symbols in mergeable sections (such as debug_str) have to be emitted as named symbols. I tried a few other ways to do this but they all didn't work for various reasons: 1) Canonicalize the MCSymbolData in RecordRelocation, nulling out the Fragment (so it didn't have to be updated by CompressDebugSection). This doesn't work because some code relies on symbols having fragments to indicate that they're defined, I think. 2) Canonicalize the MCSymbolData in RecordRelocation to be "first fragment + absolute offset" so it would be cheaper to just test and update the fragment in CompressDebugSections. This doesn't work because the offset computed in RecordRelocation isn't that of the symbol's fragment, it's the passed in fragment (I haven't figured out what that fragment is - perhaps it's the location where the relocation is to be written). And if the fragment offset has to be computed only for this use we might as well just do it when we need to, in CompressDebugSection. I also added an assert to help catch this a bit more clearly, even though it is UB. The test case improvements would either assert fail and/or valgrind vail without the fix, even if they wouldn't necessarily fail the FileCheck output. llvm-svn: 206653
2014-04-19 05:24:12 +08:00
DebugInfo: Support for compressed debug info sections 1) When creating a .debug_* section and instead create a .zdebug_ section. 2) When creating a fragment in a .zdebug_* section, make it a compressed fragment. 3) When computing the size of a compressed section, compress the data and use the size of the compressed data. 4) Emit the compressed bytes. Also, check that only if a section has a compressed fragment, then that is the only fragment in the section. Assert-fail if the fragment's data is modified after it is compressed. Initial review on llvm-commits by Eric Christopher and Rafael Espindola. llvm-svn: 204958
2014-03-28 04:45:58 +08:00
.section .debug_line,"",@progbits
Debug Compression: Avoid compression debug_frame for now Turns out debug_frame does use multiple fragments, so it doesn't compress correctly with the current approach. Disable compressing it for now while I figure out what's the best solution for it. llvm-svn: 205059
2014-03-29 05:48:31 +08:00
.section .debug_abbrev,"",@progbits
Update the fragments of symbols in compressed sections. While unnamed relocations are already cached in side tables in ELFObjectWriter::RecordRelocation, symbols still need their fragments updated to refer to the newly compressed fragment (even if that fragment isn't big enough to fit the offset). Even though we only create temporary symbols in debug info sections this comes up in 32 bit builds where even temporary symbols in mergeable sections (such as debug_str) have to be emitted as named symbols. I tried a few other ways to do this but they all didn't work for various reasons: 1) Canonicalize the MCSymbolData in RecordRelocation, nulling out the Fragment (so it didn't have to be updated by CompressDebugSection). This doesn't work because some code relies on symbols having fragments to indicate that they're defined, I think. 2) Canonicalize the MCSymbolData in RecordRelocation to be "first fragment + absolute offset" so it would be cheaper to just test and update the fragment in CompressDebugSections. This doesn't work because the offset computed in RecordRelocation isn't that of the symbol's fragment, it's the passed in fragment (I haven't figured out what that fragment is - perhaps it's the location where the relocation is to be written). And if the fragment offset has to be computed only for this use we might as well just do it when we need to, in CompressDebugSection. I also added an assert to help catch this a bit more clearly, even though it is UB. The test case improvements would either assert fail and/or valgrind vail without the fix, even if they wouldn't necessarily fail the FileCheck output. llvm-svn: 206653
2014-04-19 05:24:12 +08:00
.Lsection_abbrev:
Debug Compression: Avoid compression debug_frame for now Turns out debug_frame does use multiple fragments, so it doesn't compress correctly with the current approach. Disable compressing it for now while I figure out what's the best solution for it. llvm-svn: 205059
2014-03-29 05:48:31 +08:00
.byte 1 # Abbreviation Code
Reimplement debug info compression by compressing the whole section, rather than a fragment. 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. llvm-svn: 205990
2014-04-11 05:53:53 +08:00
.byte 17 # DW_TAG_compile_unit
.byte 0 # DW_CHILDREN_no
Update the fragments of symbols in compressed sections. While unnamed relocations are already cached in side tables in ELFObjectWriter::RecordRelocation, symbols still need their fragments updated to refer to the newly compressed fragment (even if that fragment isn't big enough to fit the offset). Even though we only create temporary symbols in debug info sections this comes up in 32 bit builds where even temporary symbols in mergeable sections (such as debug_str) have to be emitted as named symbols. I tried a few other ways to do this but they all didn't work for various reasons: 1) Canonicalize the MCSymbolData in RecordRelocation, nulling out the Fragment (so it didn't have to be updated by CompressDebugSection). This doesn't work because some code relies on symbols having fragments to indicate that they're defined, I think. 2) Canonicalize the MCSymbolData in RecordRelocation to be "first fragment + absolute offset" so it would be cheaper to just test and update the fragment in CompressDebugSections. This doesn't work because the offset computed in RecordRelocation isn't that of the symbol's fragment, it's the passed in fragment (I haven't figured out what that fragment is - perhaps it's the location where the relocation is to be written). And if the fragment offset has to be computed only for this use we might as well just do it when we need to, in CompressDebugSection. I also added an assert to help catch this a bit more clearly, even though it is UB. The test case improvements would either assert fail and/or valgrind vail without the fix, even if they wouldn't necessarily fail the FileCheck output. llvm-svn: 206653
2014-04-19 05:24:12 +08:00
.byte 27 # DW_AT_comp_dir
.byte 14 # DW_FORM_strp
Reimplement debug info compression by compressing the whole section, rather than a fragment. 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. llvm-svn: 205990
2014-04-11 05:53:53 +08:00
.byte 0 # EOM(1)
.byte 0 # EOM(2)
Compress debug sections only when beneficial. Both ZLIB and the debug info compressed section header ("ZLIB" + the size of the uncompressed data) take some constant overhead so in some cases the compressed data is actually larger than the uncompressed data. In these cases, just don't compress or rename the section at all. llvm-svn: 206659
2014-04-19 05:52:26 +08:00
.section .debug_info,"",@progbits
.long 12 # Length of Unit
.short 4 # DWARF version number
.long .Lsection_abbrev # Offset Into Abbrev. Section
.byte 8 # Address Size (in bytes)
.byte 1 # Abbrev [1] DW_TAG_compile_unit
.long .Linfo_string0 # DW_AT_comp_dir
DebugInfo: Support for compressed debug info sections 1) When creating a .debug_* section and instead create a .zdebug_ section. 2) When creating a fragment in a .zdebug_* section, make it a compressed fragment. 3) When computing the size of a compressed section, compress the data and use the size of the compressed data. 4) Emit the compressed bytes. Also, check that only if a section has a compressed fragment, then that is the only fragment in the section. Assert-fail if the fragment's data is modified after it is compressed. Initial review on llvm-commits by Eric Christopher and Rafael Espindola. llvm-svn: 204958
2014-03-28 04:45:58 +08:00
.text
foo:
.cfi_startproc
.file 1 "Driver.ii"
Compress debug sections only when beneficial. Both ZLIB and the debug info compressed section header ("ZLIB" + the size of the uncompressed data) take some constant overhead so in some cases the compressed data is actually larger than the uncompressed data. In these cases, just don't compress or rename the section at all. llvm-svn: 206659
2014-04-19 05:52:26 +08:00
# pad out the line table to make sure it's big enough to warrant compression
DebugInfo: Support for compressed debug info sections 1) When creating a .debug_* section and instead create a .zdebug_ section. 2) When creating a fragment in a .zdebug_* section, make it a compressed fragment. 3) When computing the size of a compressed section, compress the data and use the size of the compressed data. 4) Emit the compressed bytes. Also, check that only if a section has a compressed fragment, then that is the only fragment in the section. Assert-fail if the fragment's data is modified after it is compressed. Initial review on llvm-commits by Eric Christopher and Rafael Espindola. llvm-svn: 204958
2014-03-28 04:45:58 +08:00
.loc 1 2 0
nop
Compress debug sections only when beneficial. Both ZLIB and the debug info compressed section header ("ZLIB" + the size of the uncompressed data) take some constant overhead so in some cases the compressed data is actually larger than the uncompressed data. In these cases, just don't compress or rename the section at all. llvm-svn: 206659
2014-04-19 05:52:26 +08:00
.loc 1 3 0
nop
.loc 1 4 0
nop
.loc 1 5 0
nop
.loc 1 6 0
nop
.loc 1 7 0
nop
.loc 1 8 0
nop
DebugInfo: Support for compressed debug info sections 1) When creating a .debug_* section and instead create a .zdebug_ section. 2) When creating a fragment in a .zdebug_* section, make it a compressed fragment. 3) When computing the size of a compressed section, compress the data and use the size of the compressed data. 4) Emit the compressed bytes. Also, check that only if a section has a compressed fragment, then that is the only fragment in the section. Assert-fail if the fragment's data is modified after it is compressed. Initial review on llvm-commits by Eric Christopher and Rafael Espindola. llvm-svn: 204958
2014-03-28 04:45:58 +08:00
.cfi_endproc
.cfi_sections .debug_frame
Update the fragments of symbols in compressed sections. While unnamed relocations are already cached in side tables in ELFObjectWriter::RecordRelocation, symbols still need their fragments updated to refer to the newly compressed fragment (even if that fragment isn't big enough to fit the offset). Even though we only create temporary symbols in debug info sections this comes up in 32 bit builds where even temporary symbols in mergeable sections (such as debug_str) have to be emitted as named symbols. I tried a few other ways to do this but they all didn't work for various reasons: 1) Canonicalize the MCSymbolData in RecordRelocation, nulling out the Fragment (so it didn't have to be updated by CompressDebugSection). This doesn't work because some code relies on symbols having fragments to indicate that they're defined, I think. 2) Canonicalize the MCSymbolData in RecordRelocation to be "first fragment + absolute offset" so it would be cheaper to just test and update the fragment in CompressDebugSections. This doesn't work because the offset computed in RecordRelocation isn't that of the symbol's fragment, it's the passed in fragment (I haven't figured out what that fragment is - perhaps it's the location where the relocation is to be written). And if the fragment offset has to be computed only for this use we might as well just do it when we need to, in CompressDebugSection. I also added an assert to help catch this a bit more clearly, even though it is UB. The test case improvements would either assert fail and/or valgrind vail without the fix, even if they wouldn't necessarily fail the FileCheck output. llvm-svn: 206653
2014-04-19 05:24:12 +08:00
[MC/ELF] - Fixed insufficient compression.s test Main problem that .debug_info section was used to check that llvm-dwarfdump is able to decompress data that was compressed with llvm-mc tool. This section was not compressed actually, because consumes more space in compressed view. I changed testcase to use .debug_str section which is one that is really compressed. So currently test do what is probably was expected to do: checks that "data"->llvm-mc->llvm-dwarfdump->dumps back initial "data". Differential revision: http://reviews.llvm.org/D20466 llvm-svn: 270560
2016-05-24 21:45:29 +08:00
# Below is the section we will use to check that after compression with llvm-mc,
# llvm-dwarfdump tool will be able to decompress data back and dump it. Data sample
# should be compressable enough, so it is filled with some amount of equal symbols at the end
Update the fragments of symbols in compressed sections. While unnamed relocations are already cached in side tables in ELFObjectWriter::RecordRelocation, symbols still need their fragments updated to refer to the newly compressed fragment (even if that fragment isn't big enough to fit the offset). Even though we only create temporary symbols in debug info sections this comes up in 32 bit builds where even temporary symbols in mergeable sections (such as debug_str) have to be emitted as named symbols. I tried a few other ways to do this but they all didn't work for various reasons: 1) Canonicalize the MCSymbolData in RecordRelocation, nulling out the Fragment (so it didn't have to be updated by CompressDebugSection). This doesn't work because some code relies on symbols having fragments to indicate that they're defined, I think. 2) Canonicalize the MCSymbolData in RecordRelocation to be "first fragment + absolute offset" so it would be cheaper to just test and update the fragment in CompressDebugSections. This doesn't work because the offset computed in RecordRelocation isn't that of the symbol's fragment, it's the passed in fragment (I haven't figured out what that fragment is - perhaps it's the location where the relocation is to be written). And if the fragment offset has to be computed only for this use we might as well just do it when we need to, in CompressDebugSection. I also added an assert to help catch this a bit more clearly, even though it is UB. The test case improvements would either assert fail and/or valgrind vail without the fix, even if they wouldn't necessarily fail the FileCheck output. llvm-svn: 206653
2014-04-19 05:24:12 +08:00
.section .debug_str,"MS",@progbits,1
.Linfo_string0:
[MC/ELF] - Fixed insufficient compression.s test Main problem that .debug_info section was used to check that llvm-dwarfdump is able to decompress data that was compressed with llvm-mc tool. This section was not compressed actually, because consumes more space in compressed view. I changed testcase to use .debug_str section which is one that is really compressed. So currently test do what is probably was expected to do: checks that "data"->llvm-mc->llvm-dwarfdump->dumps back initial "data". Differential revision: http://reviews.llvm.org/D20466 llvm-svn: 270560
2016-05-24 21:45:29 +08:00
.asciz "perfectly compressable data sample *****************************************"