[llvm] e06d6ed - [SamplePGO] Handle FS discriminators in SampleProfileMatcher (#90858)

[via llvm-commits]

Author: Krzysztof Pszeniczny
Date: 2024-05-02T10:32:37-07:00
New Revision: e06d6ed1ef081eb9858da8066a6036c5dde432eb

URL: https://github.com/llvm/llvm-project/commit/e06d6ed1ef081eb9858da8066a6036c5dde432eb
DIFF: https://github.com/llvm/llvm-project/commit/e06d6ed1ef081eb9858da8066a6036c5dde432eb.diff

LOG: [SamplePGO] Handle FS discriminators in SampleProfileMatcher (#90858)

Currently the code uses FunctionSamples::getCallSiteIdentifier which
will sometimes incorrectly guess that FSAFDO discriminators are probe
based and will convert them incorrectly.

This change doesn't affect builds which don't use FSAFDO, it only fixes
sample profile matching with FS discriminators.

The test for this is manually updated to use discriminator value 15,
which is a perfectly valid base discriminator in the FS world, but
satisfies `isPseudoProbeDiscriminator`, so
`getBaseDiscriminatorFromDiscriminator` will incorrectly extract the
probe index from it.

Note: this change only affects how the base discriminators will be
extracted when doing stale profile matching in the IR-level sample
profile loader. It doesn't add stale profile matching to the MIR-level
FS profile loader pass.

Added: 
    

Modified: 
    llvm/lib/Transforms/IPO/SampleProfileMatcher.cpp
    llvm/test/Transforms/SampleProfile/Inputs/non-probe-stale-profile-matching.prof
    llvm/test/Transforms/SampleProfile/non-probe-stale-profile-matching.ll

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Transforms/IPO/SampleProfileMatcher.cpp b/llvm/lib/Transforms/IPO/SampleProfileMatcher.cpp
index 1ca89e0091daff..142660bcc58e34 100644
--- a/llvm/lib/Transforms/IPO/SampleProfileMatcher.cpp
+++ b/llvm/lib/Transforms/IPO/SampleProfileMatcher.cpp
@@ -37,7 +37,8 @@ void SampleProfileMatcher::findIRAnchors(
       DIL = DIL->getInlinedAt();
     } while (DIL->getInlinedAt());
 
-    LineLocation Callsite = FunctionSamples::getCallSiteIdentifier(DIL);
+    LineLocation Callsite = FunctionSamples::getCallSiteIdentifier(
+        DIL, FunctionSamples::ProfileIsFS);
     StringRef CalleeName = PrevDIL->getSubprogramLinkageName();
     return std::make_pair(Callsite, CalleeName);
   };
@@ -82,7 +83,8 @@ void SampleProfileMatcher::findIRAnchors(
         if (DIL->getInlinedAt()) {
           IRAnchors.emplace(FindTopLevelInlinedCallsite(DIL));
         } else {
-          LineLocation Callsite = FunctionSamples::getCallSiteIdentifier(DIL);
+          LineLocation Callsite = FunctionSamples::getCallSiteIdentifier(
+              DIL, FunctionSamples::ProfileIsFS);
           StringRef CalleeName = GetCanonicalCalleeName(dyn_cast<CallBase>(&I));
           IRAnchors.emplace(Callsite, CalleeName);
         }

diff  --git a/llvm/test/Transforms/SampleProfile/Inputs/non-probe-stale-profile-matching.prof b/llvm/test/Transforms/SampleProfile/Inputs/non-probe-stale-profile-matching.prof
index 8e988515be8ed5..418f2c4af26460 100644
--- a/llvm/test/Transforms/SampleProfile/Inputs/non-probe-stale-profile-matching.prof
+++ b/llvm/test/Transforms/SampleProfile/Inputs/non-probe-stale-profile-matching.prof
@@ -10,12 +10,12 @@ main:9229397:0
  7: 0
  2: foo:1479916
   1: 47663
-  1.1: 46683 bar:43238
+  1.15: 46683 bar:43238
   2: 4519 bar:4932
   3: 48723
  4: foo:1505537
   1: 48604
-  1.1: 46965 bar:44479
+  1.15: 46965 bar:44479
   2: 4613 bar:4967
   3: 49087
 bar:2333388:196222

diff  --git a/llvm/test/Transforms/SampleProfile/non-probe-stale-profile-matching.ll b/llvm/test/Transforms/SampleProfile/non-probe-stale-profile-matching.ll
index eb69c18add01b8..5394a00ced86ad 100644
--- a/llvm/test/Transforms/SampleProfile/non-probe-stale-profile-matching.ll
+++ b/llvm/test/Transforms/SampleProfile/non-probe-stale-profile-matching.ll
@@ -1,6 +1,6 @@
 ; REQUIRES: x86_64-linux
 ; REQUIRES: asserts
-; RUN: opt < %s -passes=sample-profile -sample-profile-file=%S/Inputs/non-probe-stale-profile-matching.prof --salvage-stale-profile -S --debug-only=sample-profile,sample-profile-matcher,sample-profile-impl 2>&1 | FileCheck %s
+; RUN: opt < %s -passes=sample-profile -sample-profile-file=%S/Inputs/non-probe-stale-profile-matching.prof --salvage-stale-profile -S --debug-only=sample-profile,sample-profile-matcher,sample-profile-impl -profile-isfs 2>&1 | FileCheck %s
 
 ; The profiled source code:
 
@@ -51,7 +51,7 @@
 ; CHECK: Run stale profile matching for bar
 
 ; CHECK: Run stale profile matching for foo
-; CHECK: Callsite with callee:bar is matched from 1.1 to 1.1
+; CHECK: Callsite with callee:bar is matched from 1.15 to 1.15
 ; CHECK: Callsite with callee:bar is matched from 2 to 2
 
 ; CHECK: Run stale profile matching for main
@@ -183,7 +183,7 @@ attributes #3 = { mustprogress nocallback nofree nosync nounwind willreturn memo
 !15 = !DILocation(line: 7, column: 9, scope: !14)
 !16 = !DILocation(line: 7, column: 7, scope: !14)
 !17 = !DILocation(line: 7, column: 23, scope: !18)
-!18 = !DILexicalBlockFile(scope: !14, file: !10, discriminator: 2)
+!18 = !DILexicalBlockFile(scope: !14, file: !10, discriminator: 15)
 !19 = !DILocation(line: 7, column: 15, scope: !18)
 !20 = !DILocation(line: 8, column: 21, scope: !14)
 !21 = !DILocation(line: 8, column: 15, scope: !14)
@@ -201,7 +201,7 @@ attributes #3 = { mustprogress nocallback nofree nosync nounwind willreturn memo
 !33 = !DILocation(line: 14, column: 8, scope: !25)
 !34 = !DILocation(line: 14, scope: !25)
 !35 = !DILocation(line: 14, column: 21, scope: !36)
-!36 = !DILexicalBlockFile(scope: !25, file: !10, discriminator: 2)
+!36 = !DILexicalBlockFile(scope: !25, file: !10, discriminator: 15)
 !37 = !DILocation(line: 14, column: 3, scope: !36)
 !38 = !DILocation(line: 14, column: 3, scope: !39)
 !39 = !DILexicalBlockFile(scope: !25, file: !10, discriminator: 4)