The GNU assembler supports (as extension to the ABI) use of PC-relative
relocations in half16 fields, which allows writing code like:
li 1, base-.
This patch adds support for those relocation types in the assembler.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@184552 91177308-0d34-0410-b5e6-96231b3b80d8
The current code base only supports the minimum set of tls-related
relocations and @modifiers that are necessary to support compiler-
generated code. This patch extends this to the full set defined
in the ABI (and supported by the GNU assembler) for the benefit
of the assembler parser.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@184551 91177308-0d34-0410-b5e6-96231b3b80d8
This adds support for the @higher, @highera, @highest, and @highesta
modifers, including some missing relocation types.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@184550 91177308-0d34-0410-b5e6-96231b3b80d8
This adds the relocation type and other necessary infrastructure
to use the @toc@h modifier in the assembler.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@184549 91177308-0d34-0410-b5e6-96231b3b80d8
This adds necessary infrastructure to support the @h modifier.
Note that all required relocation types were already present
(and unused).
This patch provides support for using @h in the assembler;
it would also be possible to now use this feature in code
generated by the compiler, but this is not done yet.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@184548 91177308-0d34-0410-b5e6-96231b3b80d8
Now that fixup_ppc_ha16 and fixup_ppc_lo16 are being treated exactly
the same everywhere, it no longer makes sense to have two fixup types.
This patch merges them both into a single type fixup_ppc_half16,
and renames fixup_ppc_lo16_ds to fixup_ppc_half16ds for consistency.
(The half16 and half16ds names are taken from the description of
relocation types in the PowerPC ABI.)
No change in code generation expected.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@182092 91177308-0d34-0410-b5e6-96231b3b80d8
The current PowerPC MC back end distinguishes between fixup_ppc_ha16
and fixup_ppc_lo16, which are determined by the instruction the fixup
applies to, and uses this distinction to decide whether a fixup ought
to resolve to the high or the low part of a symbol address.
This isn't quite correct, however. It is valid -if unusual- assembler
to use, e.g.
li 1, symbol@ha
or
lis 1, symbol@l
Whether the high or the low part of the address is used depends solely
on the @ suffix, not on the instruction.
In addition, both
li 1, symbol
and
lis 1, symbol
are valid, assuming the symbol address fits into 16 bits; again, both
will then refer to the actual symbol value (so li will load the value
itself, while lis will load the value shifted by 16).
To fix this, two places need to be adapted. If the fixup cannot be
resolved at assembler time, a relocation needs to be emitted via
PPCELFObjectWriter::getRelocType. This routine already looks at
the VK_ type to determine the relocation. The only problem is that
will reject any _LO modifier in a ha16 fixup and vice versa. This
is simply incorrect; any of those modifiers ought to be accepted
for either fixup type.
If the fixup *can* be resolved at assembler time, adjustFixupValue
currently selects the high bits of the symbol value if the fixup
type is ha16. Again, this is incorrect; see the above example
lis 1, symbol
Now, in theory we'd have to respect a VK_ modifier here. However,
in fact common code never even attempts to resolve symbol references
using any nontrivial VK_ modifier at assembler time; it will always
fall back to emitting a reloc and letting the linker handle it.
If this ever changes, presumably there'd have to be a target callback
to resolve VK_ modifiers. We'd then have to handle @ha etc. there.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@182091 91177308-0d34-0410-b5e6-96231b3b80d8
Now that applyFixup understands differently-sized fixups, we can define
fixup_ppc_lo16/fixup_ppc_lo16_ds/fixup_ppc_ha16 to properly be 2-byte
fixups, applied at an offset of 2 relative to the start of the
instruction text.
This has the benefit that if we actually need to generate a real
relocation record, its address will come out correctly automatically,
without having to fiddle with the offset in adjustFixupOffset.
Tested on both 64-bit and 32-bit PowerPC, using external and
integrated assembler.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@181894 91177308-0d34-0410-b5e6-96231b3b80d8
This patch extends test/MC/PowerPC/ppc64-fixups.s to not only check for
the correct fixup type in the --show-encoding output, but also runs the
generated object file through llvm-readobj -r and verifies that the
correct ELF relocation records were generated.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@181453 91177308-0d34-0410-b5e6-96231b3b80d8
This patch adds support for PowerPC platform-specific variant
kinds in MCSymbolRefExpr::getVariantKindForName, and also
adds a test case to verify they are translated to the appropriate
fixup type.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@181053 91177308-0d34-0410-b5e6-96231b3b80d8
