1
0
mirror of https://github.com/RPCS3/llvm-mirror.git synced 2024-10-25 14:02:52 +02:00
llvm-mirror/lib/DebugInfo
Greg Clayton b646654f66 Improve DWARF parsing speed by improving DWARFAbbreviationDeclaration
This patch gets a DWARF parsing speed improvement by having DWARFAbbreviationDeclaration instances know if they have a fixed byte size. If an abbreviation has a fixed byte size that can be calculated given a DWARFUnit, then parsing a DIE becomes two steps: parse ULEB128 abbrev code, and then add constant size to the offset.

This patch also adds a fixed byte size to each DWARFAbbreviationDeclaration::AttributeSpec so that attributes can quickly skip their values if needed without the need to lookup the fixed for size.

Notable improvements:

- DWARFAbbreviationDeclaration::findAttributeIndex() now returns an Optional<uint32_t> instead of a uint32_t and we no longer have to look for the magic -1U return value
- Optional<uint32_t> DWARFAbbreviationDeclaration::findAttributeIndex(dwarf::Attribute attr) const;
- DWARFAbbreviationDeclaration now has a getAttributeValue() function that extracts an attribute value given a DIE offset that takes advantage of the DWARFAbbreviationDeclaration::AttributeSpec::ByteSize
- bool DWARFAbbreviationDeclaration::getAttributeValue(const uint32_t DIEOffset, const dwarf::Attribute Attr, const DWARFUnit &U, DWARFFormValue &FormValue) const;
- A DWARFAbbreviationDeclaration instance can return a fixed byte size for itself so DWARF parsing is faster:
- Optional<size_t> DWARFAbbreviationDeclaration::getFixedAttributesByteSize(const DWARFUnit &U) const;
- Any functions that used to take a "const DWARFUnit *U" that would crash if U was NULL now take a "const DWARFUnit &U" and are only called with a valid DWARFUnit

Differential Revision: https://reviews.llvm.org/D26567

llvm-svn: 286924
2016-11-15 01:23:06 +00:00
..
CodeView Fix some size_t / uint32_t ambiguity errors. 2016-11-08 22:30:11 +00:00
DWARF Improve DWARF parsing speed by improving DWARFAbbreviationDeclaration 2016-11-15 01:23:06 +00:00
MSF Add CodeViewRecordIO for reading and writing. 2016-11-02 17:05:19 +00:00
PDB Remove extra semicolon. 2016-11-12 00:23:32 +00:00
Symbolize Fix the ASan fuse-lld.cc test after LLD r280012 2016-09-01 20:28:59 +00:00
CMakeLists.txt [msf] Resubmit "Rename Msf -> MSF". 2016-07-29 20:56:36 +00:00
LLVMBuild.txt [msf] Resubmit "Rename Msf -> MSF". 2016-07-29 20:56:36 +00:00