clang

Commit Graph

Author	SHA1	Message	Date
David Green	d2ada3f873	[CodeGen] Align rtti and vtable data Previously the alignment on the newly created rtti/typeinfo data was largely not set, meaning that DataLayout::getPreferredAlignment was free to overalign it to 16 bytes. This causes unnecessary code bloat. Differential Revision: https://reviews.llvm.org/D51416 git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@342053 91177308-0d34-0410-b5e6-96231b3b80d8	2018-09-12 14:09:06 +00:00
Peter Collingbourne	3382b3d801	CodeGen: New vtable group representation: struct of vtable arrays. In a future change, this representation will allow us to use the new inrange annotation on getelementptr to allow the optimizer to split vtable groups. Differential Revision: https://reviews.llvm.org/D22296 git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@289584 91177308-0d34-0410-b5e6-96231b3b80d8	2016-12-13 20:40:39 +00:00
Benjamin Kramer	70b4a91e1a	CodeGen: Use a fixed alignment for vtables. Pointer-sized alignment is sufficient as we only ever read single values from the table. Otherwise we'd bump the alignment to 16 bytes in the backend if the vtable is larger than 16 bytes. This is great for structures that are accessed with vector instructions or copied around, but that's simply not the case for vtables. Shrinks the data segment of a Release x86_64 clang by 0.3%. The wins are larger for i386 and code bases that use vtables more often than we do. This matches the behavior of GCC 5. git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@217495 91177308-0d34-0410-b5e6-96231b3b80d8	2014-09-10 12:50:59 +00:00

Author

SHA1

Message

Date

David Green

d2ada3f873

[CodeGen] Align rtti and vtable data

Previously the alignment on the newly created rtti/typeinfo data was largely
not set, meaning that DataLayout::getPreferredAlignment was free to overalign
it to 16 bytes. This causes unnecessary code bloat.

Differential Revision: https://reviews.llvm.org/D51416


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@342053 91177308-0d34-0410-b5e6-96231b3b80d8

2018-09-12 14:09:06 +00:00

Peter Collingbourne

3382b3d801

CodeGen: New vtable group representation: struct of vtable arrays.

In a future change, this representation will allow us to use the new inrange
annotation on getelementptr to allow the optimizer to split vtable groups.

Differential Revision: https://reviews.llvm.org/D22296

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@289584 91177308-0d34-0410-b5e6-96231b3b80d8

2016-12-13 20:40:39 +00:00

Benjamin Kramer

70b4a91e1a

CodeGen: Use a fixed alignment for vtables.

Pointer-sized alignment is sufficient as we only ever read single values
from the table. Otherwise we'd bump the alignment to 16 bytes in the
backend if the vtable is larger than 16 bytes. This is great for
structures that are accessed with vector instructions or copied around, but
that's simply not the case for vtables.

Shrinks the data segment of a Release x86_64 clang by 0.3%. The wins are
larger for i386 and code bases that use vtables more often than we do.

This matches the behavior of GCC 5.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@217495 91177308-0d34-0410-b5e6-96231b3b80d8

2014-09-10 12:50:59 +00:00

3 Commits