This extends the work done in r233995 so that now getFragment (in addition to
getSection) also works for variable symbols.
With that the existing logic to decide if a-b can be computed works even if
a or b are variables. Given that, the expression evaluation can avoid expanding
variables as aggressively and that in turn lets the relocation code see the
original variable.
In order for this to work with the asm streamer, there is now a dummy fragment
per section. It is used to assign a section to a symbol when no other fragment
exists.
This patch is a joint work by Maxim Ostapenko andy myself.
llvm-svn: 249303
Transition one API from `MCSymbolData` to `MCSymbol`. The function
needs both, and the backpointer from `MCSymbolData` to `MCSymbol` is
going away.
llvm-svn: 237498
Similar to r235222, but for the weak symbol case.
In an "ideal" assembler/object format an expression would always refer to the
final value and A-B would only be computed from a section in the same
comdat as A and B with A and B strong.
Unfortunately that is not the case with debug info on ELF, so we need an
heuristic. Since we need an heuristic, we may as well use the same one as
gas:
* call weak_sym : produces a relocation, even if in the same section.
* A - weak_sym and weak_sym -A: don't produce a relocation if we can
compute it.
This fixes pr23272 and changes the fix of pr22815 to match what gas does.
llvm-svn: 235227
As pr19627 points out, every use of AliasedSymbol is likely a bug.
The main use was to avoid the oddity of a variable showing up as undefined. That
was fixed in r233995, which made these calls nops.
llvm-svn: 234169
Before when deciding if we needed a relocation in A-B, we wore only checking
if A was weak.
This fixes the asymmetry.
The "InSet" argument should probably be renamed to "ForValue", since InSet is
very MachO specific, but doing so in this patch would make it hard to read.
This fixes PR22815.
llvm-svn: 234165
The previous logic was to first try without relocations at all
and failing that stop on the first defined symbol.
That was inefficient and incorrect in the case part of the
expression could be simplified and another part could not
(see included test).
We now stop the evaluation when we get to a variable whose value
can change (i.e. is weak).
llvm-svn: 233187
symbol from an assignment. In this case the symbol did not have a fragment so
MCObjectWriter::IsSymbolRefDifferenceFullyResolved() should not have been
calling IsSymbolRefDifferenceFullyResolvedImpl() with a NULL fragment and should
just have returned false in that case.
llvm-svn: 149442
and output the dwarf line number tables. This contains the code to emit and
encode the dwarf line tables from the previously gathered information in the
MCLineSection objects. This contains all the details to encode the line and
address deltas into the dwarf line table.
To do this an MCDwarfLineAddrFragment has been added.
Also this moves the interface code out of Mach-O streamer into
MCDwarf so it should be useable by other object file formats.
There is now one call to be made from an MCObjectStreamer
EmitInstruction() method:
MCLineEntry::Make(this, getCurrentSection());
to create a line entry after each instruction is assembled.
And one call call to be made from an MCObjectStreamer Finish() method:
MCDwarfFileTable::Emit(this, DwarfLineSection);
when getContext().hasDwarfFiles() is true and is passed a object file specific
MCSection where to emit the dwarf file and the line tables.
This appears to now be correct for 32-bit targets, at least x86. But the
relocation entries for 64-bit Darwin needs some further work which is next
up to work on. So for now the 64-bit Mach-O target does not output the
dwarf file and line tables.
llvm-svn: 115157
