maxjhandsome
/
llvm-project
forked from OSchip/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Releases Wiki Activity
llvm-project/llvm/test/CodeGen/X86/xray-loop-detection.ll

Ignoring revisions in .git-blame-ignore-revs. Click here to bypass and see the normal blame view.

23 lines
671 B
LLVM
Raw Normal View History

[XRay] Fix machine verifier issues in X86 I'm not sure if this fix is the right thing to do, but it seemed to me that PATCHABLE_RET and PATCHABLE_TAIL_CALL don't have any defs. Running the following: ``` LLVM_ENABLE_MACHINE_VERIFIER=1 ./build/bin/llvm-lit -v -a test/CodeGen/X86/xray-* ``` results in the following tests to fail (along others): ``` LLVM :: CodeGen/X86/xray-attribute-instrumentation.ll LLVM :: CodeGen/X86/xray-custom-log.ll LLVM :: CodeGen/X86/xray-log-args.ll LLVM :: CodeGen/X86/xray-loop-detection.ll LLVM :: CodeGen/X86/xray-multiplerets-in-blocks.mir LLVM :: CodeGen/X86/xray-section-group.ll LLVM :: CodeGen/X86/xray-selective-instrumentation.ll LLVM :: CodeGen/X86/xray-tail-call-sled.ll LLVM :: CodeGen/X86/xray-typed-event-log.ll ``` The errors are: ``` *** Bad machine code: Explicit definition must be a register *** - function: fn - basic block: %bb.0 (0x7fa31a84d908) - instruction: PATCHABLE_RET 2560, $eax - operand 0: 2560 ``` and ``` *** Bad machine code: Explicit definition must be a register *** - function: caller - basic block: %bb.0 (0x7fbff3044108) - instruction: PATCHABLE_TAIL_CALL 3009, @callee, <regmask $bh $bl $bp $bph $bpl $bx $ebp $ebx $hbp $hbx $rbp $rbx $r12 $r13 $r14 $r15 $r12b $r13b $r14b $r15b $r12bh $r13bh $r14bh $r15bh $r12d $r13d $r14d $r15d $r12w $r13w $r14w $r15w $r12wh and 3 more...>, implicit $rsp, implicit $ssp, implicit $rsp, implicit $ssp, implicit $edi - operand 0: 3009 ``` Differential Revision: https://reviews.llvm.org/D49187 llvm-svn: 336906
2018-07-12 22:36:43 +08:00
; RUN: llc -verify-machineinstrs -filetype=asm -o - -mtriple=x86_64-unknown-linux-gnu < %s | FileCheck %s
; RUN: llc -verify-machineinstrs -filetype=asm -o - -mtriple=x86_64-darwin-unknown < %s | FileCheck %s
[XRay] Detect loops in functions being lowered Summary: This is an implementation of the loop detection logic that XRay needs to determine whether a function might take time at runtime. Without this heuristic, XRay will tend to not instrument short functions that have loops that might have runtime dependent on inputs or external values. While this implementation doesn't do any further analysis than just figuring out whether there is a loop in the MachineFunction being code-gen'ed, we're paving the way for being able to perform more sophisticated analysis of the function in the future (for example to determine whether the trip count for the loop might be constant, and make a decision on that instead). This enables us to cover more functions with the default heuristics, and potentially identify ones that have variable runtime latency just by looking for the presence of loops. Reviewers: chandlerc, rnk, pelikan Subscribers: llvm-commits Differential Revision: https://reviews.llvm.org/D32274 llvm-svn: 302103
2017-05-04 09:24:26 +08:00
[xray] Add xray-ignore-loops option XRay allows tuning by minimum function size, but also always instruments functions with loops in them. If the minimum function size is set to a large value the loop instrumention ends up causing most functions to be instrumented anyway. This adds a new flag, xray-ignore-loops, to disable the loop detection logic. Differential Revision: https://reviews.llvm.org/D72659
2020-01-18 05:24:07 +08:00
define i32 @foo(i32 %i) nounwind noinline uwtable "xray-instruction-threshold"="10" {
[XRay] Detect loops in functions being lowered Summary: This is an implementation of the loop detection logic that XRay needs to determine whether a function might take time at runtime. Without this heuristic, XRay will tend to not instrument short functions that have loops that might have runtime dependent on inputs or external values. While this implementation doesn't do any further analysis than just figuring out whether there is a loop in the MachineFunction being code-gen'ed, we're paving the way for being able to perform more sophisticated analysis of the function in the future (for example to determine whether the trip count for the loop might be constant, and make a decision on that instead). This enables us to cover more functions with the default heuristics, and potentially identify ones that have variable runtime latency just by looking for the presence of loops. Reviewers: chandlerc, rnk, pelikan Subscribers: llvm-commits Differential Revision: https://reviews.llvm.org/D32274 llvm-svn: 302103
2017-05-04 09:24:26 +08:00
entry:
br label %Test
Test:
%indvar = phi i32 [0, %entry], [%nextindvar, %Inc]
%cond = icmp eq i32 %indvar, %i
br i1 %cond, label %Exit, label %Inc
Inc:
%nextindvar = add i32 %indvar, 1
br label %Test
Exit:
%retval = phi i32 [%indvar, %Test]
ret i32 %retval
}
; CHECK-LABEL: xray_sled_0:
; CHECK-NEXT: .ascii "\353\t"
; CHECK-NEXT: nopw 512(%rax,%rax)