llvm-objdump: Do not attempt to disassemble symbols outside of section

boundaries.

It is possible to create an ELF executable where symbol from say .text
section 'points' to the address outside the section boundaries. It does
not have a sense to disassemble something outside the section.

Without this fix llvm-objdump prints finite or infinite (depends on
the executable file architecture) number of 'invalid instruction
encoding' warnings.

llvm-svn: 202083

3 files changed, 28 insertions, 0 deletions

diff --git a/llvm/test/tools/llvm-objdump/Inputs/out-of-section-sym.elf-i386 b/llvm/test/tools/llvm-objdump/Inputs/out-of-section-sym.elf-i386
new file mode 100644
index 00000000000..4c7158498ba
--- /dev/null
+++ b/llvm/test/tools/llvm-objdump/Inputs/out-of-section-sym.elf-i386
diff --git a/llvm/test/tools/llvm-objdump/Inputs/out-of-section-sym.s b/llvm/test/tools/llvm-objdump/Inputs/out-of-section-sym.s
new file mode 100644
index 00000000000..9a1349c426f
--- /dev/null
+++ b/llvm/test/tools/llvm-objdump/Inputs/out-of-section-sym.s
@@ -0,0 +1,15 @@
+// $ cat out-of-section-sym.ld
+// SECTIONS
+// {
+//   . = 0x10;
+//   .text : { _ftext = . ; *(.text) }
+//   . = 0x20;
+//   .data : { _fdata = . ; *(.data) }
+// }
+// as --32 out-of-section-sym.s -o out-of-section-sym.o
+// ld -m elf_i386 -Tout-of-section-sym.ld -o out-of-section-sym.elf-i386 \
+//    out-of-section-sym.o
+
+.text
+_start:
+  ret
diff --git a/llvm/test/tools/llvm-objdump/out-of-section-sym.test b/llvm/test/tools/llvm-objdump/out-of-section-sym.test
new file mode 100644
index 00000000000..f70dce6a8ed
--- /dev/null
+++ b/llvm/test/tools/llvm-objdump/out-of-section-sym.test
@@ -0,0 +1,13 @@
+// Check that llvm-objdump does not attempt to disassemble symbols outside
+// of section boundaries.
+// RUN: llvm-objdump -d -t %p/Inputs/out-of-section-sym.elf-i386 | FileCheck %s
+
+CHECK: Disassembly of section .text:
+CHECK-NEXT: _start:
+CHECK-NEXT:   10:  c3  retl
+CHECK-NEXT: SYMBOL TABLE:
+CHECK-NEXT: 00000000         *UND*  00000000
+CHECK-NEXT: 00000010 l    d  .text  00000000 .text
+CHECK-NEXT: 00000010         .text  00000000 _start
+CHECK-NEXT: 00000020         .text  00000000 _fdata
+CHECK-NEXT: 00000010         .text  00000000 _ftext