6 Commits

Author SHA1 Message Date
Fabian Parzefall
101344af1a [BOLT] Allocate FunctionFragment on heap
This changes `FunctionFragment` from being used as a temporary proxy
object to access basic block ranges to a heap-allocated object that can
store fragment-specific information.

Reviewed By: rafauler

Differential Revision: https://reviews.llvm.org/D132050
2022-08-24 10:17:17 -07:00
Fabian Parzefall
0f74d191d1 [BOLT] Generate sections for multiple fragments
This patch adds support to generate any number of sections that are
assigned to fragments of functions that are split more than two-way.
With this, a function's *nth* split fragment goes into section
`.text.cold.n`.

This also changes `FunctionLayout::erase` to make sure, that there are
no empty fragments at the end of the function. This sometimes happens
when blocks are erased from the function. To avoid creating symbols
pointing to these fragments, they need to be removed.

Reviewed By: rafauler

Differential Revision: https://reviews.llvm.org/D130521
2022-08-18 21:55:06 -07:00
Fabian Parzefall
aed75748de [BOLT] Remove old layout from function layout
To track whether a function's new layout is different from its old
layout when updating it, the old layout would be kept around in memory
indefinitely (if the new layout is different). This was used only for
debugging/logging purposes. This patch forces the caller of function
layout's update method to copy the old layout into a temporary if they
need it by removing the old layout fields.

Reviewed By: rafauler

Differential Revision: https://reviews.llvm.org/D131413
2022-08-17 15:06:17 -07:00
Fabian Parzefall
0f8412c19c [BOLT] Add main fragment to function layout
Functions that do not contain any code still have to be emitted. This
occurs on AArch64 where functions can consist only of a constant island.
To support fragment semantics in code emission, this commits adds a
guaranteed main fragment to function layout. This fragment might be
empty, but allows us omit checks whether the function is empty in most
places.

Reviewed By: rafauler

Differential Revision: https://reviews.llvm.org/D130051
2022-08-17 14:51:31 -07:00
Kazu Hirata
2febc32c9c Use llvm::erase_if (NFC) 2022-08-13 12:55:48 -07:00
Fabian Parzefall
8477bc6761 [BOLT] Add function layout class
This patch adds a dedicated class to keep track of each function's
layout. It also lays the groundwork for splitting functions into
multiple fragments (as opposed to a strict hot/cold split).

Reviewed By: maksfb

Differential Revision: https://reviews.llvm.org/D129518
2022-07-16 17:23:24 -07:00