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[Instrumentation] Add Call Graph Profile pass

Authored by Bigcheese on Jun 21 2018, 4:31 PM.

Description

[Instrumentation] Add Call Graph Profile pass

This patch adds support for generating a call graph profile from Branch Frequency Info.

The CGProfile module pass simply gets the block profile count for each BB and scans for call instructions. For each call instruction it adds an edge from the current function to the called function with the current BB block profile count as the weight.

After scanning all the functions, it generates an appending module flag containing the data. The format looks like:

!llvm.module.flags = !{!0}

!0 = !{i32 5, !"CG Profile", !1}
!1 = !{!2, !3, !4} ; List of edges
!2 = !{void ()* @a, void ()* @b, i64 32} ; Edge from a to b with a weight of 32
!3 = !{void (i1)* @freq, void ()* @a, i64 11}
!4 = !{void (i1)* @freq, void ()* @b, i64 20}

Differential Revision: https://reviews.llvm.org/D48105

llvm-svn: 335306

Details

Committed
BigcheeseJun 21 2018, 4:31 PM
Differential Revision
D48105: [llvm][Instrumentation] Add Call Graph Profile pass
Parents
rGfb762b27f27c: Ignore blacklist when generating __cfi_check_fail.
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