[llvm-readelf] - Rework how we parse the .dynamic section.

This is a result of what I found during my work on https://bugs.llvm.org/show_bug.cgi?id=41679.

Previously LLVM readelf took the information about .dynamic section
from its PT_DYNAMIC segment only. GNU tools have a bit different logic.
They also use the information from the .dynamic section header if it is available.
This patch changes the code to improve the compatibility with the GNU Binutils.

Differential revision: https://reviews.llvm.org/D61937

llvm-svn: 361165

5 files changed, 143 insertions, 5 deletions

diff --git a/llvm/test/Object/Inputs/corrupt-invalid-dynamic-table-size.elf.x86-64 b/llvm/test/Object/Inputs/corrupt-invalid-dynamic-table-size.elf.x86-64
index ee29a4162e3..2eed83cfc37 100755
--- a/llvm/test/Object/Inputs/corrupt-invalid-dynamic-table-size.elf.x86-64
+++ b/llvm/test/Object/Inputs/corrupt-invalid-dynamic-table-size.elf.x86-64
diff --git a/llvm/test/Object/corrupt.test b/llvm/test/Object/corrupt.test
index 35623b431b7..c98757885aa 100644
--- a/llvm/test/Object/corrupt.test
+++ b/llvm/test/Object/corrupt.test
@@ -62,11 +62,11 @@ RUN: not llvm-readobj --dyn-relocations \
 RUN:   %p/Inputs/corrupt-invalid-dynamic-table-offset.elf.x86-64 2>&1 | \
 RUN:   FileCheck --check-prefix=DYN-TABLE-OFFSET %s
 
-DYN-TABLE-OFFSET: error: Invalid data was encountered while parsing the file
+DYN-TABLE-OFFSET: error: PT_DYNAMIC segment offset + size exceeds the size of the file
 
 
 RUN: not llvm-readobj --dyn-relocations \
 RUN:   %p/Inputs/corrupt-invalid-dynamic-table-too-large.elf.x86-64 2>&1 | \
 RUN:   FileCheck --check-prefix=DYN-TABLE-TOO-LARGE %s
 
-DYN-TABLE-TOO-LARGE: error: Invalid data was encountered while parsing the file
+DYN-TABLE-TOO-LARGE: error: PT_DYNAMIC segment offset + size exceeds the size of the file
diff --git a/llvm/test/tools/llvm-readobj/elf-dynamic-not-in-pt-dynamic.test b/llvm/test/tools/llvm-readobj/elf-dynamic-not-in-pt-dynamic.test
new file mode 100644
index 00000000000..d52ec7696fd
--- /dev/null
+++ b/llvm/test/tools/llvm-readobj/elf-dynamic-not-in-pt-dynamic.test
@@ -0,0 +1,47 @@
+## Show that llvm-readobj/llvm-readelf tools can dump the .dynamic
+## section when it is not in a PT_DYNAMIC segment.
+
+# RUN: yaml2obj %s -o %t.o
+# RUN: llvm-readobj --dynamic-table %t.o 2>&1 | FileCheck %s
+# RUN: llvm-readelf --dynamic-table %t.o 2>&1 | FileCheck %s
+
+# CHECK:      warning: The SHT_DYNAMIC section '.dynamic' is not contained within the PT_DYNAMIC segment
+# CHECK:      DynamicSection [ (2 entries)
+# CHECK-NEXT:   Tag                Type     Name/Value
+# CHECK-NEXT:   0x0000000000000018 BIND_NOW 0x1
+# CHECK-NEXT:   0x0000000000000000 NULL     0x0
+# CHECK-NEXT: ]
+
+--- !ELF
+FileHeader:
+  Class:   ELFCLASS64
+  Data:    ELFDATA2LSB
+  Type:    ET_EXEC
+  Machine: EM_X86_64
+Sections:
+  - Name: .dynamic
+    Type: SHT_DYNAMIC
+    Flags: [SHF_ALLOC]
+    Address: 0x1000
+    AddressAlign: 0x1000
+    Entries:
+      - Tag:   DT_BIND_NOW
+        Value: 0x1
+      - Tag:   DT_NULL
+        Value: 0x0
+  - Name: .text
+    Type: SHT_PROGBITS
+    Flags: [SHF_ALLOC]
+    Address: 0x1100
+    AddressAlign: 0x100
+    Content: "00"
+ProgramHeaders:
+  - Type: PT_LOAD
+    VAddr: 0x1000
+    Sections:
+      - Section: .dynamic
+      - Section: .text
+  - Type: PT_DYNAMIC
+    VAddr: 0x1000
+    Sections:
+      - Section: .text
diff --git a/llvm/test/tools/llvm-readobj/elf-malformed-pt-dynamic.test b/llvm/test/tools/llvm-readobj/elf-malformed-pt-dynamic.test
index e762a27865f..db229b1b259 100644
--- a/llvm/test/tools/llvm-readobj/elf-malformed-pt-dynamic.test
+++ b/llvm/test/tools/llvm-readobj/elf-malformed-pt-dynamic.test
@@ -1,6 +1,5 @@
 # If the offset and/or size fields of the PT_DYNAMIC field become corrupted,
-# it will be impossible to read the dynamic segment validly. This test shows
-# that a sensible error message is given in this situation.
+# we should report a sensible error message.
 
 # Creating such a malformed file is hard. The easiest way to simulate it is to
 # truncate the file. Note that the section headers must first be stripped or
@@ -21,7 +20,7 @@
 # RUN: %python -c "with open(r'%t.truncated2', 'r+') as f: f.truncate(0xFFF)"
 # RUN: not llvm-readobj %t.truncated2 --dynamic-table 2>&1 | FileCheck %s
 
-# CHECK: error: Invalid data was encountered while parsing the file
+# CHECK: error: PT_DYNAMIC segment offset + size exceeds the size of the file
 
 --- !ELF
 FileHeader:
diff --git a/llvm/test/tools/llvm-readobj/elf-non-dynamic-in-pt-dynamic.test b/llvm/test/tools/llvm-readobj/elf-non-dynamic-in-pt-dynamic.test
new file mode 100644
index 00000000000..610148f26ff
--- /dev/null
+++ b/llvm/test/tools/llvm-readobj/elf-non-dynamic-in-pt-dynamic.test
@@ -0,0 +1,92 @@
+## Show that llvm-readobj/llvm-readelf tools can dump the .dynamic section which
+## is not alone in PT_DYNAMIC segment.
+
+## In the first case .text is placed before .dynamic.
+## We check that we warn about this case.
+
+# RUN: yaml2obj --docnum=1 %s -o %t.o
+# RUN: llvm-readobj --dynamic-table %t.o 2>&1 | FileCheck %s --check-prefixes=WARNING,CHECK
+# RUN: llvm-readelf --dynamic-table %t.o 2>&1 | FileCheck %s --check-prefixes=WARNING,CHECK
+
+# WARNING:    warning: The SHT_DYNAMIC section '.dynamic' is not at the start of PT_DYNAMIC segment
+# CHECK:      DynamicSection [ (2 entries)
+# CHECK-NEXT:   Tag                Type     Name/Value
+# CHECK-NEXT:   0x0000000000000018 BIND_NOW 0x1
+# CHECK-NEXT:   0x0000000000000000 NULL     0x0
+# CHECK-NEXT: ]
+
+--- !ELF
+FileHeader:
+  Class:   ELFCLASS64
+  Data:    ELFDATA2LSB
+  Type:    ET_EXEC
+  Machine: EM_X86_64
+Sections:
+  - Name: .text
+    Type: SHT_PROGBITS
+    Flags: [SHF_ALLOC]
+    Address: 0x1000
+    AddressAlign: 0x100
+    Content: "00"
+  - Name: .dynamic
+    Type: SHT_DYNAMIC
+    Flags: [SHF_ALLOC]
+    Address: 0x1100
+    AddressAlign: 0x1000
+    Entries:
+      - Tag:   DT_BIND_NOW
+        Value: 0x1
+      - Tag:   DT_NULL
+        Value: 0x0
+ProgramHeaders:
+  - Type: PT_LOAD
+    VAddr: 0x1000
+    Sections:
+      - Section: .text
+      - Section: .dynamic
+  - Type: PT_DYNAMIC
+    VAddr: 0x1000
+    Sections:
+      - Section: .text
+      - Section: .dynamic
+
+## In the second case .text goes after .dynamic and we don't display any warnings.
+
+# RUN: yaml2obj --docnum=2 %s -o %t.o
+# RUN: llvm-readobj --dynamic-table %t.o | FileCheck %s --implicit-check-not="warning"
+# RUN: llvm-readelf --dynamic-table %t.o | FileCheck %s --implicit-check-not="warning"
+
+--- !ELF
+FileHeader:
+  Class:   ELFCLASS64
+  Data:    ELFDATA2LSB
+  Type:    ET_EXEC
+  Machine: EM_X86_64
+Sections:
+  - Name: .dynamic
+    Type: SHT_DYNAMIC
+    Flags: [SHF_ALLOC]
+    Address: 0x1000
+    AddressAlign: 0x1000
+    Entries:
+      - Tag:   DT_BIND_NOW
+        Value: 0x1
+      - Tag:   DT_NULL
+        Value: 0x0
+  - Name: .text
+    Type: SHT_PROGBITS
+    Flags: [SHF_ALLOC]
+    Address: 0x1100
+    AddressAlign: 0x100
+    Content: "00"
+ProgramHeaders:
+  - Type: PT_LOAD
+    VAddr: 0x1000
+    Sections:
+      - Section: .dynamic
+      - Section: .text
+  - Type: PT_DYNAMIC
+    VAddr: 0x1000
+    Sections:
+      - Section: .dynamic
+      - Section: .text