Commit Graph

3 Commits

Author SHA1 Message Date
James Molloy 6110be9759 Re-apply r302416: [ARM] Clear the constant pool cache on explicit .ltorg directives
Re-applying now that PR32825 which was raised on the commit this fixed up is now known to have also been fixed by this commit.

Original commit message:
    Multiple ldr pseudoinstructions with the same constant value will
    reuse the same constant pool entry. However, if the constant pool
    is explicitly flushed with a .ltorg directive, we should not try
    to reference constants in the previous pool any longer, since they
    may be out of range.

    This fixes assembling hand-written assembler source which repeatedly
    loads the same constant value, across a binary size larger than the
    pc-relative fixup range for ldr instructions (4096 bytes). Such
    assembler source already uses explicit .ltorg instructions to emit
    constant pools with regular intervals. However if we try to reuse
    constants emitted in earlier pools, they end up out of range.

    This makes the output of the testcase match what binutils gas does
    (prior to this patch, it would fail to assemble).

    Differential Revision: https://reviews.llvm.org/D32847

llvm-svn: 303540
2017-05-22 09:42:07 +00:00
James Molloy 5cc75ae8f9 Revert "[ARM] Clear the constant pool cache on explicit .ltorg directives"
This reverts commit r302416. This was a fixup for r286006, which has now been reverted so this doesn't apply (either in concept or in code).

This commit itself has no problems, but the underlying issue it was fixing has now disappeared from the codebase.

llvm-svn: 303536
2017-05-22 08:49:28 +00:00
Martin Storsjo fd4c158a84 [ARM] Clear the constant pool cache on explicit .ltorg directives
Multiple ldr pseudoinstructions with the same constant value will
reuse the same constant pool entry. However, if the constant pool
is explicitly flushed with a .ltorg directive, we should not try
to reference constants in the previous pool any longer, since they
may be out of range.

This fixes assembling hand-written assembler source which repeatedly
loads the same constant value, across a binary size larger than the
pc-relative fixup range for ldr instructions (4096 bytes). Such
assembler source already uses explicit .ltorg instructions to emit
constant pools with regular intervals. However if we try to reuse
constants emitted in earlier pools, they end up out of range.

This makes the output of the testcase match what binutils gas does
(prior to this patch, it would fail to assemble).

Differential Revision: https://reviews.llvm.org/D32847

llvm-svn: 302416
2017-05-08 10:26:24 +00:00