- .eh_frame_hdr contains a binary-searchable data structure for finding an FDE. If present, we can use this
section to avoid having to parse the entire FDE/CIE list in the binary, instead only entries that are actually
required for unwinding are read.
- rework the inputs pc-relative pointer decoding to support both already-mapped sections as well as sections
mapped from a file
- store the VirtualMachine on UnwindContext so the allocations can be reused
Most of this migration was performed automatically with `zig fmt`. There
were a few exceptions which I had to manually fix:
* `@alignCast` and `@addrSpaceCast` cannot be automatically rewritten
* `@truncate`'s fixup is incorrect for vectors
* Test cases are not formatted, and their error locations change
This data changed quite significantly between DWARF 4 and 5. Some
systems are shipping DWARF 5 libraries (Void Linux on musl libc seems to
use it for crt1 etc), which meant when printing stack traces, a random
compile unit might be incorrectly identified as containing an address,
resulting in incorrect location information.
I was consistently experiencing this issue with compiler stack traces,
and this change fixed it.
* CompileStep: Avoid calling producesPdbFile() to determine whether the
option should be respected. If the user asks for it, put it on the
command line and let the Zig CLI deal with it appropriately.
* Make the namespace of `std.dwarf.Format.dwarf32` no longer have a
redundant "dwarf" in it.
* Add `zig cc` integration for `-gdwarf32` and `-gdwarf64`.
* Toss in a bonus bug fix for `-gdwarf-2`, `-gdwarf-3`, etc.
* Avoid using default init values for struct fields unnecessarily.
* Add missing cache hash addition for the new option.
This commit enables producing 64-bit DWARF format for Zig executables
that are produced through the LLVM backend. This is achieved by exposing
both command-line flags and CompileStep flags. The production of the
64-bit format only affects binaries that use the DWARF format and it is
disabled on MacOS due to it being problematic. This commit, despite
generating the interface for the Zig user to be able to tell the compile
which format is wanted, is just implemented for the LLVM backend, so
clang and the self-hosted backends will need this to be implemented in a
future commit.
This is an effort to work around #7962, since the emission of the 64-bit
format automatically produces 64-bit relocations. Further investigation
will be needed to make DWARF 32-bit format to emit bigger relocations
when needed and not make the linker angry.
There are still a few occurrences of "stage1" in the standard library
and self-hosted compiler source, however, these instances need a bit
more careful inspection to ensure no breakage.
* Added support for stroffsetsptr class in Dwarf stdlib
* Proper initializion of debug_str_offsets in DwarfInfo
* Added missing null initializer to DwarfInfo in Macho
* Added missing is_64 field to getAttrString in DwarfInfo
* Fixed formatting
* Added missing is_64 param to getAttrString
* Added required cast to usize
* Adding missing .debug_str_offsets initialization
* getAttrString now uses the str_offsets_base attr
While this code probably could do with some love and a redesign,
this commit fixes the allocations by making sure we explicitly
pass an allocator where required, and we use arenas for temporary
or narrowly-scoped objects such as a `Die` (for `Die` in particular,
not every `FormValue` will be allocated - we could duplicate, or
we can use an arena which is the proposal of this commit).
DWARF 5 moves around some fields and adds a few new ones that can't be
parsed or ignored by our current DWARF 4 parser. This isn't a complete
implementation of DWARF 5, but this is enough to make stack traces
mostly work. Line numbers from C++ don't show up, but I know the info
is there. I think the answer is to iterate through .debug_line_str in
getLineNumberInfo, but I didn't want to fall into an even deeper rabbit
hole tonight.
We already have a LICENSE file that covers the Zig Standard Library. We
no longer need to remind everyone that the license is MIT in every single
file.
Previously this was introduced to clarify the situation for a fork of
Zig that made Zig's LICENSE file harder to find, and replaced it with
their own license that required annual payments to their company.
However that fork now appears to be dead. So there is no need to
reinforce the copyright notice in every single file.
* Move leb128 out of debug and remove trivial *mem functions as discussed in #5588
* Turns out one of the *Mem functions was used by MachO. Replaced with trivial use of FixedBufferStream.
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