From b6020c330d3826aa542164842d6ba71fdee3650b Mon Sep 17 00:00:00 2001
From: Xing GUO <higuoxing@gmail.com>
Date: Thu, 4 Jun 2020 09:25:26 +0800
Subject: [PATCH] [ObjectYAML][ELF] Let the endianness of DWARF sections be
 inferred from FileHeader.

This patch helps infer the endianness of DWARF sections from `FileHeader`.

Reviewed By: jhenderson, grimar

Differential Revision: https://reviews.llvm.org/D81051
---
 llvm/lib/ObjectYAML/ELFYAML.cpp                    |  3 +
 .../tools/yaml2obj/ELF/DWARF/debug-aranges.yaml    | 65 +++++++++++++++++++++-
 2 files changed, 66 insertions(+), 2 deletions(-)

diff --git a/llvm/lib/ObjectYAML/ELFYAML.cpp b/llvm/lib/ObjectYAML/ELFYAML.cpp
index 250f97d..98a40c9 100644
--- a/llvm/lib/ObjectYAML/ELFYAML.cpp
+++ b/llvm/lib/ObjectYAML/ELFYAML.cpp
@@ -1654,6 +1654,9 @@ void MappingTraits<ELFYAML::Object>::mapping(IO &IO, ELFYAML::Object &Object) {
   IO.mapOptional("Symbols", Object.Symbols);
   IO.mapOptional("DynamicSymbols", Object.DynamicSymbols);
   IO.mapOptional("DWARF", Object.DWARF);
+  if (Object.DWARF)
+    Object.DWARF->IsLittleEndian =
+        Object.Header.Data == ELFYAML::ELF_ELFDATA(ELF::ELFDATA2LSB);
   IO.setContext(nullptr);
 }
 
diff --git a/llvm/test/tools/yaml2obj/ELF/DWARF/debug-aranges.yaml b/llvm/test/tools/yaml2obj/ELF/DWARF/debug-aranges.yaml
index 6c4556d..0d8b4ee 100644
--- a/llvm/test/tools/yaml2obj/ELF/DWARF/debug-aranges.yaml
+++ b/llvm/test/tools/yaml2obj/ELF/DWARF/debug-aranges.yaml
@@ -4,8 +4,8 @@
 
 ## Generate and verify a big endian object file.
 
-# RUN: yaml2obj --docnum=1 -DENDIAN=ELFDATA2MSB %s -o %t1.o
-# RUN: llvm-readobj --sections --section-data %t1.o | \
+# RUN: yaml2obj --docnum=1 -DENDIAN=ELFDATA2MSB %s -o %t.be.o
+# RUN: llvm-readobj --sections --section-data %t.be.o | \
 # RUN:   FileCheck %s -DADDRALIGN=1 -DSIZE=96 --check-prefixes=DWARF-BE-HEADER,DWARF-BE-CONTENT
 
 #       DWARF-BE-HEADER: Index: 1
@@ -90,6 +90,67 @@ DWARF:
         - Address: 0x0000000056780000
           Length:  0x10
 
+## Generate and verify a little endian object file.
+
+# RUN: yaml2obj --docnum=1 -DENDIAN=ELFDATA2LSB %s -o %t.le.o
+# RUN: llvm-readobj --sections --section-data %t.le.o | \
+# RUN:   FileCheck %s --check-prefixes=DWARF-LE-DEFAULT
+
+#      DWARF-LE-DEFAULT: Section {
+#      DWARF-LE-DEFAULT:   Index: 1
+# DWARF-LE-DEFAULT-NEXT:   Name: .debug_aranges (1)
+# DWARF-LE-DEFAULT-NEXT:   Type: SHT_PROGBITS (0x1)
+# DWARF-LE-DEFAULT-NEXT:   Flags [ (0x0)
+# DWARF-LE-DEFAULT-NEXT:   ]
+# DWARF-LE-DEFAULT-NEXT:   Address: 0x0
+# DWARF-LE-DEFAULT-NEXT:   Offset: 0x40
+# DWARF-LE-DEFAULT-NEXT:   Size: 96
+# DWARF-LE-DEFAULT-NEXT:   Link: 0
+# DWARF-LE-DEFAULT-NEXT:   Info: 0
+# DWARF-LE-DEFAULT-NEXT:   AddressAlignment: 1
+# DWARF-LE-DEFAULT-NEXT:   EntrySize: 0
+# DWARF-LE-DEFAULT-NEXT:   SectionData (
+# DWARF-LE-DEFAULT-NEXT:     0000: 2C000000 02000000 00000400 00000000
+##                                 |        |   |        | |  |
+##                                 |        |   |        | |  +------- Padding zeros (4-byte)
+##                                 |        |   |        | +- SegSize (1-byte) 0x00
+##                                 |        |   |        +- AddrSize (1-byte) 0x04
+##                                 |        |   +-------- CuOffset (4-byte) 0x00
+##                                 |        +--- Version (2-byte) 0x02
+##                                 +------- InitialLength (4-byte) 0x2c
+##
+# DWARF-LE-DEFAULT-NEXT:     0010: 34120000 20000000 00000000 00000000
+##                                 |        |        |
+##                                 |        |        +---------------- Terminating Entry
+##                                 |        +------- Length (4-byte) 0x20
+##                                 +------- Address (4-byte) 0x1234
+##
+# DWARF-LE-DEFAULT-NEXT:     0020: 2C000000 02006500 00000800 00000000
+##                                 |        |   |        | |  |
+##                                 |        |   |        | |  +------- Padding zeros (4-byte)
+##                                 |        |   |        | +- SegSize (1-byte) 0x00
+##                                 |        |   |        +- AddrSize (1-byte) 0x08
+##                                 |        |   +-------- CuOffset (4-byte) 0x00
+##                                 |        +--- Version (2-byte) 0x02
+##                                 +------- InitialLength (4-byte) 0x2c
+##
+# DWARF-LE-DEFAULT-NEXT:     0030: 78560000 00000000 20000000 00000000
+##                                 |                 |
+##                                 |                 +---------------- Length (8-byte) 0x20
+##                                 +---------------- Address (8-byte) 0x5678
+##
+# DWARF-LE-DEFAULT-NEXT:     0040: 00007856 00000000 10000000 00000000
+##                                 |                 |
+##                                 |                 +---------------- Length (8-byte) 0x10
+##                                 +---------------- Address (8-byte) 0x5678
+##                           
+# DWARF-LE-DEFAULT-NEXT:     0050: 00000000 00000000 00000000 00000000
+##                                 |
+##                                 +---------------------------------- Terminating entry
+##
+# DWARF-LE-DEFAULT-NEXT:   )
+# DWARF-LE-DEFAULT-NEXT: }
+
 ## b) Generate the .debug_aranges section from raw section content.
 
 # RUN: yaml2obj --docnum=2 %s -o %t2.o
-- 
2.7.4