[PATCH] D66358: [llvm-readobj] Fallback to PT_NOTE if file doesn't have sections

[Petr Hosek via Phabricator via llvm-commits]

phosek created this revision.
phosek added reviewers: rupprecht, jhenderson, alexshap.
Herald added subscribers: llvm-commits, seiya.
Herald added a project: LLVM.

This is useful when trying to read notes from stripped files and matches
the behavior of GNU readelf and eu-readelf.


Repository:
  rL LLVM

https://reviews.llvm.org/D66358

Files:
  llvm/test/tools/llvm-readobj/gnu-notes.test
  llvm/tools/llvm-readobj/ELFDumper.cpp


Index: llvm/tools/llvm-readobj/ELFDumper.cpp
===================================================================
--- llvm/tools/llvm-readobj/ELFDumper.cpp
+++ llvm/tools/llvm-readobj/ELFDumper.cpp
@@ -4502,7 +4502,7 @@
     }
   };
 
-  if (Obj->getHeader()->e_type == ELF::ET_CORE) {
+  if (Obj->getHeader()->e_type == ELF::ET_CORE || Obj->sections()->empty()) {
     for (const auto &P :
          unwrapOrError(this->FileName, Obj->program_headers())) {
       if (P.p_type != PT_NOTE)
Index: llvm/test/tools/llvm-readobj/gnu-notes.test
===================================================================
--- llvm/test/tools/llvm-readobj/gnu-notes.test
+++ llvm/test/tools/llvm-readobj/gnu-notes.test
@@ -3,6 +3,8 @@
 # RUN: yaml2obj --docnum=1 %s > %t1.so
 # RUN: llvm-readelf --notes %t1.so | FileCheck %s --check-prefix=GNU --strict-whitespace --match-full-lines
 # RUN: llvm-readobj --notes %t1.so | FileCheck %s --check-prefix=LLVM
+# RUN: llvm-objcopy --strip-all %t1.so
+# RUN: llvm-readobj --notes %t1.so | FileCheck %s --check-prefix=LLVM-STRIPPED
 
 #      GNU:Displaying notes found at file offset 0x00000200 with length 0x00000020:
 # GNU-NEXT:  Owner                Data size 	Description
@@ -53,6 +55,19 @@
 # LLVM-NEXT:   }
 # LLVM-NEXT: ]
 
+# LLVM-STRIPPED:      Notes [
+# LLVM-STRIPPED-NEXT:   NoteSection {
+# LLVM-STRIPPED-NEXT:     Offset: 0x40
+# LLVM-STRIPPED-NEXT:     Size: 0x20
+# LLVM-STRIPPED-NEXT:     Note {
+# LLVM-STRIPPED-NEXT:       Owner: GNU
+# LLVM-STRIPPED-NEXT:       Data size: 0x10
+# LLVM-STRIPPED-NEXT:       Type: NT_GNU_BUILD_ID (unique build ID bitstring)
+# LLVM-STRIPPED-NEXT:       Build ID: 4fcb712aa6387724a9f465a32cd8c14b
+# LLVM-STRIPPED-NEXT:     }
+# LLVM-STRIPPED-NEXT:   }
+# LLVM-STRIPPED-NEXT: ]
+
 --- !ELF
 FileHeader:
   Class:   ELFCLASS64


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