Adding Matching and Inference Functionality to Propeller-PR3: Read basic block hashes from propeller profile. #164223

wdx727 · 2025-10-20T09:05:22Z

Adding Matching and Inference Functionality to Propeller. For detailed information, please refer to the following RFC: https://discourse.llvm.org/t/rfc-adding-matching-and-inference-functionality-to-propeller/86238.
This is the third PR, which is used to read basic block hashes from the propeller profile. The associated PRs are:
PR1: #160706
PR2: #162963

co-authors: lifengxiang1025 lifengxiang@kuaishou.com; zcfh wuminghui03@kuaishou.com

rlavaee

Please add a test for this. Just to make sure that the hashes are read and errors can be detected (like basic-block-sections-clusters-error.ll).

rlavaee · 2025-10-27T16:47:42Z

llvm/lib/CodeGen/BasicBlockSectionsProfileReader.cpp

@@ -287,6 +296,25 @@ Error BasicBlockSectionsProfileReader::ReadV1Profile() {
      }
      continue;
    }
+    case 'h': { // Basic block hash secifier.
+      // Skip the profile when we the profile iterator (FI) refers to the


Remove 'we'.

rlavaee · 2025-10-27T16:49:56Z

llvm/lib/CodeGen/BasicBlockSectionsProfileReader.cpp

+        if (getAsUnsignedInteger(BBIDStr, 10, BBID))
+          return createProfileParseError(Twine("unsigned integer expected: '") +
+                                         BBIDStr + "'");
+        HashStr.consume_front("0x");


Maybe we don't need to print 0x at all and assume that the hash is always hexadecimal.

rlavaee · 2025-10-27T17:03:14Z

llvm/lib/CodeGen/BasicBlockSectionsProfileReader.cpp

@@ -493,6 +521,12 @@ uint64_t BasicBlockSectionsProfileReaderWrapperPass::getEdgeCount(
  return BBSPR.getEdgeCount(FuncName, SrcBBID, SinkBBID);
 }

+std::pair<bool, FunctionPathAndClusterInfo>
+BasicBlockSectionsProfileReaderWrapperPass::getFunctionPathAndClusterInfo(


I don't see this being used in this PR.

This method will be used in the next PR, and we have removed it from this PR.

llvmbot · 2025-10-28T07:58:14Z

@llvm/pr-subscribers-backend-x86

Author: None (wdx727)

Changes

Adding Matching and Inference Functionality to Propeller. For detailed information, please refer to the following RFC: https://discourse.llvm.org/t/rfc-adding-matching-and-inference-functionality-to-propeller/86238.
This is the third PR, which is used to read basic block hashes from the propeller profile. The associated PRs are:
PR1: #160706
PR2: #162963

co-authors: lifengxiang1025 [lifengxiang@kuaishou.com](mailto:lifengxiang@kuaishou.com); zcfh [wuminghui03@kuaishou.com](mailto:wuminghui03@kuaishou.com)

Full diff: https://github.com/llvm/llvm-project/pull/164223.diff

4 Files Affected:

(modified) llvm/include/llvm/CodeGen/BasicBlockSectionsProfileReader.h (+2)
(modified) llvm/lib/CodeGen/BasicBlockSectionsProfileReader.cpp (+18)
(added) llvm/test/CodeGen/X86/basic-block-sections-bb-hash.ll (+48)
(modified) llvm/test/CodeGen/X86/basic-block-sections-clusters-error.ll (+14-1)

diff --git a/llvm/include/llvm/CodeGen/BasicBlockSectionsProfileReader.h b/llvm/include/llvm/CodeGen/BasicBlockSectionsProfileReader.h
index 48650a6df22ff..4114c02c39f06 100644
--- a/llvm/include/llvm/CodeGen/BasicBlockSectionsProfileReader.h
+++ b/llvm/include/llvm/CodeGen/BasicBlockSectionsProfileReader.h
@@ -54,6 +54,8 @@ struct FunctionPathAndClusterInfo {
   DenseMap<UniqueBBID, uint64_t> NodeCounts;
   // Edge counts for each edge, stored as a nested map.
   DenseMap<UniqueBBID, DenseMap<UniqueBBID, uint64_t>> EdgeCounts;
+  // Hash for each basic block.
+  DenseMap<unsigned, uint64_t> BBHashes;
 };
 
 class BasicBlockSectionsProfileReader {
diff --git a/llvm/lib/CodeGen/BasicBlockSectionsProfileReader.cpp b/llvm/lib/CodeGen/BasicBlockSectionsProfileReader.cpp
index fbcd614b85d18..67b56de904e91 100644
--- a/llvm/lib/CodeGen/BasicBlockSectionsProfileReader.cpp
+++ b/llvm/lib/CodeGen/BasicBlockSectionsProfileReader.cpp
@@ -287,6 +287,24 @@ Error BasicBlockSectionsProfileReader::ReadV1Profile() {
       }
       continue;
     }
+    case 'h': { // Basic block hash secifier.
+      // Skip the profile when the profile iterator (FI) refers to the
+      // past-the-end element.
+      if (FI == ProgramPathAndClusterInfo.end())
+        continue;
+      for (auto BBIDHashStr : Values) {
+        auto [BBIDStr, HashStr] = BBIDHashStr.split(':');
+        unsigned long long BBID = 0, Hash = 0;
+        if (getAsUnsignedInteger(BBIDStr, 10, BBID))
+          return createProfileParseError(Twine("unsigned integer expected: '") +
+                                         BBIDStr + "'");
+        if (getAsUnsignedInteger(HashStr, 16, Hash))
+          return createProfileParseError(Twine("unsigned integer expected: '") +
+                                         HashStr + "'");
+        FI->second.BBHashes[BBID] = Hash;
+      }
+      continue;
+    }
     default:
       return createProfileParseError(Twine("invalid specifier: '") +
                                      Twine(Specifier) + "'");
diff --git a/llvm/test/CodeGen/X86/basic-block-sections-bb-hash.ll b/llvm/test/CodeGen/X86/basic-block-sections-bb-hash.ll
new file mode 100644
index 0000000000000..0c249d7c0618f
--- /dev/null
+++ b/llvm/test/CodeGen/X86/basic-block-sections-bb-hash.ll
@@ -0,0 +1,48 @@
+; BB section test with basic block hashes.
+;
+; RUN: llc %s -O0 -mtriple=x86_64-pc-linux -function-sections -filetype=obj -basic-block-address-map -emit-bb-hash -o %t.o
+; RUN: obj2yaml %t.o -o %t.yaml
+;
+;; Profile for version 1:
+; RUN: echo 'v1' > %t
+; RUN: echo 'f foo' >> %t
+; RUN: echo 'g 0:10,1:9,2:1 1:8,3:8 2:2,3:2 3:11' >> %t
+; RUN: echo 'c 0 2 3' >> %t
+; RUN: grep -E '^\s+(- ID:|Hash:)' %t.yaml | \
+; RUN: grep -B1 'Hash:' | \
+; RUN: sed 's/^\s*//; s/^- ID: *//; s/Hash: *0x//' | \
+; RUN: paste -d: - - | \
+; RUN: tr '\n' ' ' | \
+; RUN: sed 's/ $/\n/; s/^/h /' >> %t
+;
+; RUN: llc < %s -O0 -mtriple=x86_64-pc-linux -function-sections -basic-block-sections=%t | FileCheck %s
+;
+define void @foo(i1 zeroext) nounwind {
+  %2 = alloca i8, align 1
+  %3 = zext i1 %0 to i8
+  store i8 %3, ptr %2, align 1
+  %4 = load i8, ptr %2, align 1
+  %5 = trunc i8 %4 to i1
+  br i1 %5, label %6, label %8
+
+6:                                                ; preds = %1
+  %7 = call i32 @bar()
+  br label %10
+
+8:                                                ; preds = %1
+  %9 = call i32 @baz()
+  br label %10
+
+10:                                               ; preds = %8, %6
+  ret void
+}
+
+declare i32 @bar() #1
+
+declare i32 @baz() #1
+
+; CHECK: .section	.text.foo,"ax",@progbits
+; CHECK: callq baz
+; CHECK: retq
+; CHECK: .section	.text.split.foo,"ax",@progbits
+; CHECK: callq bar
diff --git a/llvm/test/CodeGen/X86/basic-block-sections-clusters-error.ll b/llvm/test/CodeGen/X86/basic-block-sections-clusters-error.ll
index 751ab76722c07..dadc94e0566a7 100644
--- a/llvm/test/CodeGen/X86/basic-block-sections-clusters-error.ll
+++ b/llvm/test/CodeGen/X86/basic-block-sections-clusters-error.ll
@@ -69,7 +69,20 @@
 ; RUN: echo 'g 0:4,1:2:3' >> %t15
 ; RUN: not --crash llc < %s -O0 -mtriple=x86_64 -function-sections -basic-block-sections=%t15 2>&1 | FileCheck %s --check-prefix=CHECK-ERROR15
 ; CHECK-ERROR15: LLVM ERROR: invalid profile {{.*}} at line 4: unsigned integer expected: '2:3'
-
+; RUN: echo 'v1' > %t16
+; RUN: echo 'f dummy1' >> %t16
+; RUN: echo 'c 0 1' >> %t16
+; RUN: echo 'g 0:4,1:2' >> %t16
+; RUN: echo 'h a:1111111111111111 1:ffffffffffffffff' >> %t16
+; RUN: not --crash llc < %s -O0 -mtriple=x86_64 -function-sections -basic-block-sections=%t16 2>&1 | FileCheck %s --check-prefix=CHECK-ERROR16
+; CHECK-ERROR16: LLVM ERROR: invalid profile {{.*}} at line 5: unsigned integer expected: 'a'
+; RUN: echo 'v1' > %t17
+; RUN: echo 'f dummy1' >> %t17
+; RUN: echo 'c 0 1' >> %t17
+; RUN: echo 'g 0:4,1:2' >> %t17
+; RUN: echo 'h 0:111111111111111g 1:ffffffffffffffff' >> %t17
+; RUN: not --crash llc < %s -O0 -mtriple=x86_64 -function-sections -basic-block-sections=%t17 2>&1 | FileCheck %s --check-prefix=CHECK-ERROR17
+; CHECK-ERROR17: LLVM ERROR: invalid profile {{.*}} at line 5: unsigned integer expected: '111111111111111g'
 
 define i32 @dummy1(i32 %x, i32 %y, i32 %z) {
   entry:

wdx727 · 2025-10-28T08:41:51Z

Please add a test for this. Just to make sure that the hashes are read and errors can be detected (like basic-block-sections-clusters-error.ll).

Done.

rlavaee · 2025-10-30T15:27:46Z

llvm/include/llvm/CodeGen/BasicBlockSectionsProfileReader.h

  DenseMap<UniqueBBID, uint64_t> NodeCounts;
  // Edge counts for each edge, stored as a nested map.
  DenseMap<UniqueBBID, DenseMap<UniqueBBID, uint64_t>> EdgeCounts;
+  // Hash for each basic block.


Please update the comment to clarify that hashes are stored for every original block (not cloned blocks), hence the map key being unsigned instead of UniqueBBID.

rlavaee · 2025-10-30T15:28:45Z

llvm/lib/CodeGen/BasicBlockSectionsProfileReader.cpp

+          return createProfileParseError(Twine("unsigned integer expected: '") +
+                                         BBIDStr + "'");
+        if (getAsUnsignedInteger(HashStr, 16, Hash))
+          return createProfileParseError(Twine("unsigned integer expected: '") +


Maybe say "unsigned integer expected in hex format" here.

rlavaee · 2025-10-30T15:35:07Z

llvm/test/CodeGen/X86/basic-block-sections-bb-hash.ll

+; RUN: echo 'f foo' >> %t
+; RUN: echo 'g 0:10,1:9,2:1 1:8,3:8 2:2,3:2 3:11' >> %t
+; RUN: echo 'c 0 2 3' >> %t
+; RUN: grep -E '^\s+(- ID:|Hash:)' %t.yaml | \


Could you please explain these commands with a comment? Looks like it's reading the SHT_LLVM_BB_ADDR_MAP for hashes and then putting them into the basic blocks sections profile.

You are right. We have added the comment.

github-actions · 2025-10-30T15:53:19Z

✅ With the latest revision this PR passed the C/C++ code formatter.

…sic block hashes from propeller profile. Co-authored-by: lifengxiang1025 <lifengxiang@kuaishou.com> Co-authored-by: zcfh <wuminghui03@kuaishou.com>

rlavaee · 2025-10-30T19:36:03Z

Let me know if/when you want me to merge this upstream.

wdx727 · 2025-10-30T19:41:47Z

Let me know if/when you want me to merge this upstream.

Thank you. I need you to help merge this PR.

rlavaee · 2025-10-30T21:33:39Z

FYI, I simplified the test here to satisfy the buildbots: 4afb0e6f
We can revisit the issue in later PRs when the hash is actually checked.

wdx727 · 2025-10-31T01:57:12Z

FYI, I simplified the test here to satisfy the buildbots: 4afb0e6f We can revisit the issue in later PRs when the hash is actually checked.

Thanks.

…sic block hashes from propeller profile. (llvm#164223) Adding Matching and Inference Functionality to Propeller. For detailed information, please refer to the following RFC: https://discourse.llvm.org/t/rfc-adding-matching-and-inference-functionality-to-propeller/86238. This is the third PR, which is used to read basic block hashes from the propeller profile. The associated PRs are: PR1: llvm#160706 PR2: llvm#162963 co-authors: lifengxiang1025 [lifengxiang@kuaishou.com](mailto:lifengxiang@kuaishou.com); zcfh [wuminghui03@kuaishou.com](mailto:wuminghui03@kuaishou.com) Co-authored-by: lifengxiang1025 <lifengxiang@kuaishou.com> Co-authored-by: zcfh <wuminghui03@kuaishou.com>

llvmbot added the llvm:codegen label Oct 20, 2025

wdx727 force-pushed the propeller_bb_hash_3 branch 2 times, most recently from 35c4f40 to 549da06 Compare October 21, 2025 01:57

lifengxiang1025 requested a review from rlavaee October 21, 2025 09:04

rlavaee reviewed Oct 27, 2025

View reviewed changes

wdx727 force-pushed the propeller_bb_hash_3 branch from 549da06 to f5ae6cd Compare October 28, 2025 07:57

llvmbot added the backend:X86 label Oct 28, 2025

wdx727 force-pushed the propeller_bb_hash_3 branch 2 times, most recently from 3892abf to 1f62e8e Compare October 28, 2025 08:07

wdx727 force-pushed the propeller_bb_hash_3 branch from 1f62e8e to d1db0ae Compare October 28, 2025 09:43

wdx727 requested a review from rlavaee October 30, 2025 02:57

rlavaee reviewed Oct 30, 2025

View reviewed changes

wdx727 force-pushed the propeller_bb_hash_3 branch from d1db0ae to aadce86 Compare October 30, 2025 15:51

Adding Matching and Inference Functionality to Propeller-PR3: Read ba…

c990315

…sic block hashes from propeller profile. Co-authored-by: lifengxiang1025 <lifengxiang@kuaishou.com> Co-authored-by: zcfh <wuminghui03@kuaishou.com>

wdx727 force-pushed the propeller_bb_hash_3 branch from aadce86 to c990315 Compare October 30, 2025 15:57

rlavaee approved these changes Oct 30, 2025

View reviewed changes

rlavaee merged commit fe52f1d into llvm:main Oct 30, 2025
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Adding Matching and Inference Functionality to Propeller-PR4: Implement matching and inference and create clusters #165868

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Adding Matching and Inference Functionality to Propeller-PR3: Read basic block hashes from propeller profile. #164223

Adding Matching and Inference Functionality to Propeller-PR3: Read basic block hashes from propeller profile. #164223

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