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

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

Differential Revision: https://reviews.llvm.org/D66358

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@369169 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/test/tools/llvm-readobj/gnu-notes.test b/test/tools/llvm-readobj/gnu-notes.test
index aab3ec34b6194a0df82c1338c730f27c63e7497b..dbd869c3a6ee003202646579ec4c2f7fa78ba877 100644 (file)
--- a/test/tools/llvm-readobj/gnu-notes.test
+++ b/test/tools/llvm-readobj/gnu-notes.test
@@ -3,18 +3,21 @@
 # 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-sections %t1.so %t1.stripped.so
+# RUN: llvm-readelf --notes %t1.stripped.so | FileCheck %s --check-prefix=GNU-STRIPPED --strict-whitespace --match-full-lines
+# RUN: llvm-readobj --notes %t1.stripped.so | FileCheck %s --check-prefix=LLVM-STRIPPED
 
-#      GNU:Displaying notes found at file offset 0x00000200 with length 0x00000020:
+#      GNU:Displaying notes found at file offset 0x00000238 with length 0x00000020:
 # GNU-NEXT:  Owner                Data size    Description
 # GNU-NEXT:  GNU                  0x00000010   NT_GNU_ABI_TAG (ABI version tag)
 # GNU-NEXT:    OS: Linux, ABI: 2.6.32
 
-#      GNU:Displaying notes found at file offset 0x00000220 with length 0x00000020:
+#      GNU:Displaying notes found at file offset 0x00000258 with length 0x00000020:
 # GNU-NEXT:  Owner                Data size    Description
 # GNU-NEXT:  GNU                  0x00000010   NT_GNU_BUILD_ID (unique build ID bitstring)
 # GNU-NEXT:    Build ID: 4fcb712aa6387724a9f465a32cd8c14b
 
-#      GNU:Displaying notes found at file offset 0x00000240 with length 0x0000001c:
+#      GNU:Displaying notes found at file offset 0x00000278 with length 0x0000001c:
 # GNU-NEXT:  Owner                Data size    Description
 # GNU-NEXT:  GNU                  0x00000009   NT_GNU_GOLD_VERSION (gold version)
 # GNU-NEXT:    Version: gold 1.11
@@ -53,6 +56,24 @@
 # 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: ]
+
+#      GNU-STRIPPED:Displaying notes found at file offset 0x00000040 with length 0x00000020:
+# GNU-STRIPPED-NEXT:  Owner                Data size   Description
+# GNU-STRIPPED-NEXT:  GNU                  0x00000010  NT_GNU_BUILD_ID (unique build ID bitstring)
+# GNU-STRIPPED-NEXT:    Build ID: 4fcb712aa6387724a9f465a32cd8c14b
+
 --- !ELF
 FileHeader:
   Class:   ELFCLASS64
@@ -74,6 +95,11 @@ Sections:
     Type:         SHT_NOTE
     AddressAlign: 0x0000000000000004
     Content:      040000000900000004000000474E5500676F6C6420312E3131000000
+ProgramHeaders:
+  - Type: PT_NOTE
+    FileSize: 0x20
+    Sections:
+      - Section: .note.gnu.build-id
 
 ## Test tools report an error if a note section has an invalid offset
 ## that goes past the end of file.

diff --git a/tools/llvm-readobj/ELFDumper.cpp b/tools/llvm-readobj/ELFDumper.cpp
index 08e511a00c43c43cbc4e5a743d2e78735e1ae276..1e24504afd46113f0aa00d94edc1b593d95dfd96 100644 (file)
--- a/tools/llvm-readobj/ELFDumper.cpp
+++ b/tools/llvm-readobj/ELFDumper.cpp
@@ -4502,7 +4502,7 @@ void GNUStyle<ELFT>::printNotes(const ELFFile<ELFT> *Obj) {
     }
   };
 
-  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)
@@ -5703,7 +5703,7 @@ void LLVMStyle<ELFT>::printNotes(const ELFFile<ELFT> *Obj) {
     }
   };
 
-  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)