Initial support for dumping DWARF corresponding to Swift code

The DWARF data for Swift code has a top-level DW_TAG_module DIE as the
child of the DW_TAG_compile_unit DIE and the parent of the
DW_TAG_subprogram DIEs that dump_syms uses to locate functions.
dump_syms needs to process DW_TAG_module DIEs as introducing nested
scopes to make it work with Swift.

This also reworks demangling to be language-specific, so that the C++
demangler isn't invoked when processing Swift code. The DWARF data for
Swift code presents its mangled names in the same form as used for C++
(DW_AT_MIPS_linkage_name or DW_AT_linkage_name) but the mangling is
Swift-specific (beginning with _T instead of _Z). There is no
programmatic interface to a Swift name demangler as an analogue to C++'s
__cxa_demangle(), so mangled Swift names are exposed as-is. Xcode's
"xcrun swift-demangle" can be used to post-process these mangled Swift
names on macOS.

Support for mangled names presented in a DW_AT_linkage_name attribute,
as used by DWARF 4, is added. This supersedes the earlier use of
DW_AT_MIPS_linkage_name.

BUG=google-breakpad:702,google-breakpad:715
R=ted.mielczarek@gmail.com

Review URL: https://codereview.chromium.org/2147523005 .
This commit is contained in:
Mark Mentovai 2016-09-23 14:22:42 -04:00
parent 138886803c
commit 7398ce15b7
6 changed files with 130 additions and 33 deletions

View file

@ -232,6 +232,8 @@ enum DwarfAttribute {
DW_AT_call_column = 0x57,
DW_AT_call_file = 0x58,
DW_AT_call_line = 0x59,
// DWARF 4
DW_AT_linkage_name = 0x6e,
// SGI/MIPS extensions.
DW_AT_MIPS_fde = 0x2001,
DW_AT_MIPS_loop_begin = 0x2002,
@ -499,7 +501,7 @@ enum DwarfOpcode {
DW_OP_call_frame_cfa =0x9c,
DW_OP_bit_piece =0x9d,
DW_OP_lo_user =0xe0,
DW_OP_hi_user =0xff,
DW_OP_hi_user =0xff,
// GNU extensions
DW_OP_GNU_push_tls_address =0xe0,
// Extensions for Fission. See http://gcc.gnu.org/wiki/DebugFission.
@ -542,6 +544,7 @@ enum DwarfLanguage
DW_LANG_ObjC_plus_plus =0x0011,
DW_LANG_UPC =0x0012,
DW_LANG_D =0x0013,
DW_LANG_Swift =0x001e,
// Implementation-defined language code range.
DW_LANG_lo_user = 0x8000,
DW_LANG_hi_user = 0xffff,
@ -668,7 +671,7 @@ enum DwarfPointerEncoding
// encoding (except DW_EH_PE_aligned), and indicates that the
// encoded value represents the address at which the true address
// is stored, not the true address itself.
DW_EH_PE_indirect = 0x80
DW_EH_PE_indirect = 0x80
};
} // namespace dwarf2reader