commit e8b376547b4b77671c36607ade025d3272699e7a
Author: Wei Mi <wmi@google.com>
Date:   Fri Sep 24 15:20:16 2021 -0700

    Fixed a bug in https://reviews.llvm.org/rG8eb617d719bdc6a4ed7773925d2421b9bbdd4b7a.
    
    For compressed profile when reading an unknown section, the data reader pointer
    adjustment was incorrect. This patch fixed that.
---
 llvm/include/llvm/ProfileData/SampleProfReader.h         |   2 +-
 .../Inputs/unknown.section.compressed.extbin.profdata    | Bin 0 -> 401 bytes
 llvm/test/tools/llvm-profdata/forward-compatible.test    |  15 +++++++++++++++
 3 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/llvm/include/llvm/ProfileData/SampleProfReader.h b/llvm/include/llvm/ProfileData/SampleProfReader.h
index 169ba28965fb..e6d31f1b9098 100644
--- a/llvm/include/llvm/ProfileData/SampleProfReader.h
+++ b/llvm/include/llvm/ProfileData/SampleProfReader.h
@@ -787,7 +787,7 @@ private:
   virtual std::error_code
   readCustomSection(const SecHdrTableEntry &Entry) override {
     // Update the data reader pointer to the end of the section.
-    Data += Entry.Size;
+    Data = End;
     return sampleprof_error::success;
   };
 
diff --git a/llvm/test/tools/llvm-profdata/Inputs/unknown.section.compressed.extbin.profdata b/llvm/test/tools/llvm-profdata/Inputs/unknown.section.compressed.extbin.profdata
new file mode 100644
index 000000000000..f08c7ba3d562
Binary files /dev/null and b/llvm/test/tools/llvm-profdata/Inputs/unknown.section.compressed.extbin.profdata differ
diff --git a/llvm/test/tools/llvm-profdata/forward-compatible.test b/llvm/test/tools/llvm-profdata/forward-compatible.test
index 50c79a0d3e51..8d45ba7d8a73 100644
--- a/llvm/test/tools/llvm-profdata/forward-compatible.test
+++ b/llvm/test/tools/llvm-profdata/forward-compatible.test
@@ -1,11 +1,15 @@
 RUN: llvm-profdata show -sample %S/Inputs/unknown.section.extbin.profdata | FileCheck %s
+RUN: llvm-profdata show -sample %S/Inputs/unknown.section.compressed.extbin.profdata | FileCheck %s
 RUN: llvm-profdata show -sample -show-sec-info-only %S/Inputs/unknown.section.extbin.profdata | FileCheck %s -check-prefix=HDR
+RUN: llvm-profdata show -sample -show-sec-info-only %S/Inputs/unknown.section.compressed.extbin.profdata | FileCheck %s -check-prefix=HDR-COMPRESS
 
 # The input unknown.section.extbin.profdata contains an unknown section type
 # which uses an enum value which won't be used in the near future. Check
 # llvm-profdata can read it without problem. This is to ensure adding new
 # section in extbinary format for SampleFDO won't cause forward compatibility
 # issue.
+# unknown.section.compressed.extbin.profdata is the compressed version of
+# unknown.section.extbin.profdata.
 
 CHECK: Function: main: 366846, 0, 3 sampled lines
 CHECK-NEXT: Samples collected in the function's body {
@@ -24,3 +28,14 @@ HDR-NEXT: FunctionMetadata - Offset: 394, Size: 0, Flags: {}
 HDR-NEXT: Header Size: 242
 HDR-NEXT: Total Sections Size: 152
 HDR-NEXT: File Size: 394
+
+HDR-COMPRESS: ProfileSummarySection - Offset: 242, Size: 89, Flags: {compressed}
+HDR-COMPRESS-NEXT: NameTableSection - Offset: 331, Size: 16, Flags: {compressed}
+HDR-COMPRESS-NEXT: UnknownSection - Offset: 347, Size: 11, Flags: {compressed}
+HDR-COMPRESS-NEXT: FuncOffsetTableSection - Offset: 388, Size: 13, Flags: {compressed}
+HDR-COMPRESS-NEXT: LBRProfileSection - Offset: 358, Size: 30, Flags: {compressed}
+HDR-COMPRESS-NEXT: ProfileSymbolListSection - Offset: 388, Size: 0, Flags: {compressed}
+HDR-COMPRESS-NEXT: FunctionMetadata - Offset: 401, Size: 0, Flags: {compressed}
+HDR-COMPRESS-NEXT: Header Size: 242
+HDR-COMPRESS-NEXT: Total Sections Size: 159
+HDR-COMPRESS-NEXT: File Size: 401