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llvm-project/llvm/test/Transforms/MemProfContextDisambiguation/recursive.ll
Teresa Johnson b9e4bde804
[MemProf] Re-enable cloning of callsites in recursive cycles with fixes (#125947) 
This change addresses a number of issues with the support added by
PR121985 which were exposed through more exhaustive testing,
specifically places that needed updates to perform correct graph updates
in the presence of cycles.

A new test case is added that reproduces these issues, and the default
is flipped back to enabling this handling.
2025-02-06 08:04:42 -08:00

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8.6 KiB
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;; Test recursion handling during cloning.
;;
;; Original code looks like:
;;
;; #include <stdlib.h>
;; #include <string.h>
;; #include <unistd.h>
;; __attribute((noinline)) char *D() {
;; return new char[10];
;; }
;; __attribute((noinline)) char *B(int n);
;; __attribute((noinline)) char *C(int n) {
;; if (!n) {
;; return D();
;; }
;; return B(n-1);
;; }
;; __attribute((noinline)) char *B(int n) {
;; return C(n);
;; }
;; int main(int argc, char **argv) {
;; char *x = B(1);
;; char *y = B(1);
;; char *z = B(0);
;; memset(x, 0, 10);
;; memset(y, 0, 10);
;; memset(z, 0, 10);
;; free(x);
;; sleep(200);
;; free(y);
;; free(z);
;; return 0;
;; }
;;
;; The IR was then reduced using llvm-reduce with the expected FileCheck input.
;; Check behavior when we enable cloning of contexts involved with recursive
;; cycles, but not through the cycle itself. I.e. until full support for
;; recursion is added, the cloned recursive call from C back to B (line 12) will
;; not be updated to call a clone.
; RUN: opt -passes=memprof-context-disambiguation -supports-hot-cold-new \
; RUN: -memprof-verify-ccg -memprof-verify-nodes \
; RUN: -pass-remarks=memprof-context-disambiguation \
; RUN: -memprof-allow-recursive-callsites=true \
; RUN: %s -S 2>&1 | FileCheck %s \
; RUN: --implicit-check-not "memprof_recursive3.cc:12:10: call in clone _Z1Ci.memprof.1 assigned" \
; RUN: --check-prefix=ALL --check-prefix=ALLOW-RECUR-CALLSITES --check-prefix=ALLOW-RECUR-CONTEXTS
;; Skipping recursive callsites should result in no cloning.
; RUN: opt -passes=memprof-context-disambiguation -supports-hot-cold-new \
; RUN: -memprof-verify-ccg -memprof-verify-nodes \
; RUN: -pass-remarks=memprof-context-disambiguation \
; RUN: -memprof-allow-recursive-callsites=false \
; RUN: %s -S 2>&1 | FileCheck %s \
; RUN: --implicit-check-not "memprof_recursive3.cc:12:10: call in clone _Z1Ci.memprof.1 assigned" \
; RUN: --implicit-check-not="created clone" \
; RUN: --implicit-check-not="marked with memprof allocation attribute cold" \
; RUN: --check-prefix=ALL
;; Check the default behavior (enabled recursive callsites).
; RUN: opt -passes=memprof-context-disambiguation -supports-hot-cold-new \
; RUN: -memprof-verify-ccg -memprof-verify-nodes \
; RUN: -pass-remarks=memprof-context-disambiguation \
; RUN: %s -S 2>&1 | FileCheck %s \
; RUN: --implicit-check-not "memprof_recursive3.cc:12:10: call in clone _Z1Ci.memprof.1 assigned" \
; RUN: --check-prefix=ALL --check-prefix=ALLOW-RECUR-CALLSITES --check-prefix=ALLOW-RECUR-CONTEXTS
;; Skipping recursive contexts should prevent spurious call to cloned version of
;; B from the context starting at memprof_recursive.cc:19:13, which is actually
;; recursive (until that support is added).
; RUN: opt -passes=memprof-context-disambiguation -supports-hot-cold-new \
; RUN: -memprof-verify-ccg -memprof-verify-nodes \
; RUN: -pass-remarks=memprof-context-disambiguation \
; RUN: -memprof-allow-recursive-callsites=true \
; RUN: -memprof-allow-recursive-contexts=false \
; RUN: %s -S 2>&1 | FileCheck %s \
; RUN: --implicit-check-not "memprof_recursive3.cc:12:10: call in clone _Z1Ci.memprof.1 assigned" \
; RUN: --check-prefix=ALL --check-prefix=ALLOW-RECUR-CALLSITES --check-prefix=SKIP-RECUR-CONTEXTS
; ALLOW-RECUR-CALLSITES: memprof_recursive.cc:4:0: created clone _Z1Dv.memprof.1
; ALLOW-RECUR-CALLSITES: memprof_recursive.cc:8:0: created clone _Z1Ci.memprof.1
; ALLOW-RECUR-CALLSITES: memprof_recursive.cc:14:0: created clone _Z1Bi.memprof.1
; ALLOW-RECUR-CALLSITES: memprof_recursive.cc:20:13: call in clone main assigned to call function clone _Z1Bi.memprof.1
;; We should only call the cold clone for the recursive context if we enabled
;; recursive contexts via -memprof-allow-recursive-contexts=true (default).
; ALLOW-RECUR-CONTEXTS: memprof_recursive.cc:19:13: call in clone main assigned to call function clone _Z1Bi.memprof.1
; ALLOW-RECUR-CALLSITES: memprof_recursive.cc:15:10: call in clone _Z1Bi.memprof.1 assigned to call function clone _Z1Ci.memprof.1
; ALLOW-RECUR-CALLSITES: memprof_recursive.cc:10:12: call in clone _Z1Ci.memprof.1 assigned to call function clone _Z1Dv.memprof.1
; ALLOW-RECUR-CALLSITES: memprof_recursive.cc:5:10: call in clone _Z1Dv.memprof.1 marked with memprof allocation attribute cold
;; We should call the original B for the recursive context if we have
;; disabled recursive contexts via -memprof-allow-recursive-contexts=false.
; SKIP-RECUR-CONTEXTS: memprof_recursive.cc:19:13: call in clone main assigned to call function clone _Z1Bi
; ALLOW-RECUR-CALLSITES: memprof_recursive.cc:12:10: call in clone _Z1Ci assigned to call function clone _Z1Bi
; ALLOW-RECUR-CALLSITES: memprof_recursive.cc:18:13: call in clone main assigned to call function clone _Z1Bi
; ALLOW-RECUR-CALLSITES: memprof_recursive.cc:15:10: call in clone _Z1Bi assigned to call function clone _Z1Ci
; ALLOW-RECUR-CALLSITES: memprof_recursive.cc:10:12: call in clone _Z1Ci assigned to call function clone _Z1Dv
; ALL: memprof_recursive.cc:5:10: call in clone _Z1Dv marked with memprof allocation attribute notcold
target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
define ptr @_Z1Dv() !dbg !3 {
entry:
%call = tail call ptr @_Znam(i64 10), !dbg !6, !memprof !7, !callsite !14
ret ptr null
}
define ptr @_Z1Ci(i32 %n) !dbg !15 {
entry:
%call = tail call ptr @_Z1Dv(), !dbg !16, !callsite !17
br label %return
if.end: ; No predecessors!
%call1 = tail call ptr @_Z1Bi(i32 0), !dbg !18, !callsite !19
br label %return
return: ; preds = %if.end, %entry
ret ptr null
}
define ptr @_Z1Bi(i32 %n) !dbg !20 {
entry:
%call = tail call ptr @_Z1Ci(i32 0), !dbg !21, !callsite !22
ret ptr null
}
define i32 @main() {
entry:
%call = tail call ptr @_Z1Bi(i32 0), !dbg !23, !callsite !25
%call1 = tail call ptr @_Z1Bi(i32 0), !dbg !26, !callsite !27
%call2 = tail call ptr @_Z1Bi(i32 0), !dbg !28, !callsite !29
ret i32 0
}
declare ptr @_Znam(i64)
!llvm.dbg.cu = !{!0}
!llvm.module.flags = !{!2}
!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !1, producer: "clang version 20.0.0git (https://github.com/llvm/llvm-project.git 7aec6dc477f8148ed066d10dfc7a012a51b6599c)", isOptimized: true, runtimeVersion: 0, emissionKind: LineTablesOnly, splitDebugInlining: false, debugInfoForProfiling: true, nameTableKind: None)
!1 = !DIFile(filename: "memprof_recursive.cc", directory: ".", checksumkind: CSK_MD5, checksum: "2f15f63b187a0e0d40e7fdd18b10576a")
!2 = !{i32 2, !"Debug Info Version", i32 3}
!3 = distinct !DISubprogram(name: "D", linkageName: "_Z1Dv", scope: !1, file: !1, line: 4, type: !4, scopeLine: 4, flags: DIFlagPrototyped | DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0)
!4 = !DISubroutineType(types: !5)
!5 = !{}
!6 = !DILocation(line: 5, column: 10, scope: !3)
!7 = !{!8, !10, !12}
!8 = !{!9, !"cold"}
!9 = !{i64 6541423618768552252, i64 -200552803509692312, i64 -2954124005641725917, i64 6307901912192269588}
!10 = !{!11, !"notcold"}
!11 = !{i64 6541423618768552252, i64 -200552803509692312, i64 -2954124005641725917, i64 -7155190423157709404, i64 -2954124005641725917, i64 8632435727821051414}
!12 = !{!13, !"cold"}
!13 = !{i64 6541423618768552252, i64 -200552803509692312, i64 -2954124005641725917, i64 -7155190423157709404, i64 -2954124005641725917, i64 -3421689549917153178}
!14 = !{i64 6541423618768552252}
!15 = distinct !DISubprogram(name: "C", linkageName: "_Z1Ci", scope: !1, file: !1, line: 8, type: !4, scopeLine: 8, flags: DIFlagPrototyped | DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0)
!16 = !DILocation(line: 10, column: 12, scope: !15)
!17 = !{i64 -200552803509692312}
!18 = !DILocation(line: 12, column: 10, scope: !15)
!19 = !{i64 -7155190423157709404}
!20 = distinct !DISubprogram(name: "B", linkageName: "_Z1Bi", scope: !1, file: !1, line: 14, type: !4, scopeLine: 14, flags: DIFlagPrototyped | DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0)
!21 = !DILocation(line: 15, column: 10, scope: !20)
!22 = !{i64 -2954124005641725917}
!23 = !DILocation(line: 18, column: 13, scope: !24)
!24 = distinct !DISubprogram(name: "main", scope: !1, file: !1, line: 17, type: !4, scopeLine: 17, flags: DIFlagPrototyped | DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0)
!25 = !{i64 8632435727821051414}
!26 = !DILocation(line: 19, column: 13, scope: !24)
!27 = !{i64 -3421689549917153178}
!28 = !DILocation(line: 20, column: 13, scope: !24)
!29 = !{i64 6307901912192269588}
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