Commit Graph

4 Commits

Author SHA1 Message Date
Reid Kleckner fe44a531e0 [COFF] Implement /safeseh:no and check @feat.00 flags by default
Summary:
Fixes PR41828. Before this, LLD always emitted SafeSEH chunks and
defined __safe_se_handler_table & size. Now, /safeseh:no leaves those
undefined.

Additionally, we were checking for the safeseh @feat.00 flag in two
places: once to emit errors, and once during safeseh table construction.
The error was set up to be off by default, but safeseh is supposed to be
on by default. I combined the two checks, so now LLD emits an error if
an input object lacks @feat.00 and safeseh is enabled. This caused the
majority of 32-bit LLD tests to fail, since many test input object files
lack @feat.00 symbols. I explicitly added -safeseh:no to those tests to
preserve behavior.

Finally, LLD no longer sets IMAGE_DLL_CHARACTERISTICS_NO_SEH if any
input file wasn't compiled for safeseh.

Reviewers: mstorsjo, ruiu, thakis

Reviewed By: ruiu, thakis

Subscribers: llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D63570

llvm-svn: 366238
2019-07-16 18:17:33 +00:00
Zachary Turner ee9906d884 [LLD/PDB] Write actual records to the globals stream.
Previously we were writing an empty globals stream.  Windows
tools interpret this as "private symbols are not present in
this PDB", even when they are, so we need to fix this.  Regardless,
without it we don't have information about global variables, so
we need to fix it anyway.  This patch does that.

With this patch, the "lm" command in WinDbg correctly reports
that we have private symbols available, but the "dv" command
still refuses to display local variables.

Differential Revision: https://reviews.llvm.org/D36535

llvm-svn: 310743
2017-08-11 19:00:03 +00:00
Zachary Turner af8c75a8c0 [llvm-pdbutil] Output the symbol offset when dumping.
Type records have a unique type index, but symbol records do
not.  Instead, symbol records refer to other symbol records
by referencing their offset in the symbol stream.  In a sense
this is the analogue of the TypeIndex, but we are not printing
it in the dumper.  Printing it not only gives us more useful
information when manually investigating the contents of a PDB,
but also allows us to write better tests by enabling us to
verify that fields that reference other symbol records do
so correctly.

Differential Revision: https://reviews.llvm.org/D34906

llvm-svn: 306890
2017-06-30 21:35:00 +00:00
Reid Kleckner 502d4ce2e4 [COFF] Improve synthetic symbol handling
Summary:
The main change is that we can have SECREL and SECTION relocations
against ___safe_se_handler_table, which is important for handling the
debug info in the MSVCRT.

Previously we were using DefinedRelative for __safe_se_handler_table and
__ImageBase, and after we implement CFGuard, we plan to extend it to
handle __guard_fids_table, __guard_longjmp_table, and more.  However,
DefinedRelative is really only suitable for implementing __ImageBase,
because it lacks a Chunk, which you need in order to figure out the
output section index and output section offset when resolving SECREl and
SECTION relocations.

This change renames DefinedRelative to DefinedSynthetic and gives it a
Chunk. One wart is that __ImageBase doesn't have a chunk. It points to
the PE header, effectively. We could split DefinedRelative and
DefinedSynthetic if we think that's cleaner and creates fewer special
cases.

I also added safeseh.s, which checks that we don't emit a safe seh table
entries pointing to garbage collected handlers and that we don't emit a
table at all when there are no handlers.

Reviewers: ruiu

Reviewed By: ruiu

Subscribers: inglorion, pcc, llvm-commits, aprantl

Differential Revision: https://reviews.llvm.org/D34577

llvm-svn: 306293
2017-06-26 15:39:52 +00:00