[llvm-objdump] Set --print-imm-hex by default.

[mysterymath]

Summary

This was previously attempted in 2016 by colinl's D18770, but LLD tests
were missed, which caused the change to be reverted.

Setting --print-imm-hex by default brings llvm-objdump's behavior closer
in line with objdump, and it makes it easier to read addresses and
alignment from the disassembly. It may make non-address immediates
harder to interpret, but it still seems the better default, barring more
context-sensitive base selection logic.

--no-print-imm-hex was added to the affected tests in the monorepo in a
semi-automated fashion to preserve their existing semantics.

[MaskRay]

LGTM. Please push the --no-print-imm-hex change separately and land the default-toggle change in its own so that it is more easily reverted in case there is anything not caught.

[MaskRay]

lld/test/COFF/armnt-blx23t.test

4 ↗

(On Diff #471624)

Don't wrap lines. For tests we don't stick with the 80-column rule.

If someone decides to fix the tests, they will need to join the lines.

[mysterymath]

Leave the original lines formatting alone; just insert --no-print-imm-hex after
llvm-objdump.

llvm/docs/CommandGuide/llvm-objdump.rst

 
 .. option:: --no-leading-addr, --no-addresses
 
   When disassembling, do not print leading addresses for instructions or inline
   relocations.
 
 .. option:: --no-print-imm-hex
 
-  Do not use hex format for immediate values in disassembly output (default).
+  Do not use hex format for immediate values in disassembly output.
 
 .. option:: --no-show-raw-insn
 
   When disassembling, do not print the raw bytes of each instruction.
 
 .. option:: --offloading
 
   Display the content of the LLVM offloading section.
 
 .. option:: --prefix=<prefix>
 
   When disassembling with the :option:`--source` option, prepend ``prefix`` to
   absolute paths.
 
 .. option:: --prefix-strip=<level>
 
   When disassembling with the :option:`--source` option, strip out ``level``
   initial directories from absolute paths. This option has no effect without
   :option:`--prefix`.
 
 .. option:: --print-imm-hex
 
-  Use hex format when printing immediate values in disassembly output.
+  Use hex format when printing immediate values in disassembly output (default).
 
 .. option:: -S, --source
 
   When disassembling, display source interleaved with the disassembly. Implies
   :option:`--disassemble`.
 
 .. option:: --show-lma
 

llvm/docs/ReleaseNotes.rst

 * ``llvm-readobj --elf-output-style=JSON`` no longer prefixes each JSON object
   with the file name. Previously, each object file's output looked like
   ``"main.o":{"FileSummary":{"File":"main.o"},...}`` but is now
   ``{"FileSummary":{"File":"main.o"},...}``. This allows each JSON object to be
   parsed in the same way, since each object no longer has a unique key. Tools
   that consume ``llvm-readobj``'s JSON output should update their parsers
   accordingly.
 
+* ``llvm-objdump`` now uses ``--print-imm-hex`` by default, which brings its
+  default behavior closer in line with ``objdump``.
+
 Changes to LLDB
 ---------------------------------
 
 Changes to Sanitizers
 ---------------------
 
 
 Other Changes

llvm/test/tools/llvm-objdump/X86/print-imm-hex.s

 # RUN: llvm-mc -filetype=obj -triple=x86_64 %s -o %t
 
-# RUN: llvm-objdump -d %t | FileCheck %s --check-prefix=NOPRINT
+# RUN: llvm-objdump -d %t | FileCheck %s --check-prefix=PRINT
 # RUN: llvm-objdump -d --print-imm-hex --no-print-imm-hex %t | FileCheck %s --check-prefix=NOPRINT
 # RUN: llvm-objdump -d --no-print-imm-hex --print-imm-hex %t | FileCheck %s --check-prefix=PRINT
 
 .text
   retq
   movq 0x123456(%rip),%rax
   movabs $0x5555555555555554,%rax
   lwpval $0x0, 0x40(%rdx,%rax), %r15d

llvm/tools/llvm-objdump/llvm-objdump.cpp

static void parseObjdumpOptions(const llvm::opt::InputArgList &InputArgs) {
   MachOOpt = InputArgs.hasArg(OBJDUMP_macho);
   MCPU = InputArgs.getLastArgValue(OBJDUMP_mcpu_EQ).str();
   MAttrs = commaSeparatedValues(InputArgs, OBJDUMP_mattr_EQ);
   ShowRawInsn = !InputArgs.hasArg(OBJDUMP_no_show_raw_insn);
   LeadingAddr = !InputArgs.hasArg(OBJDUMP_no_leading_addr);
   RawClangAST = InputArgs.hasArg(OBJDUMP_raw_clang_ast);
   Relocations = InputArgs.hasArg(OBJDUMP_reloc);
   PrintImmHex =
-      InputArgs.hasFlag(OBJDUMP_print_imm_hex, OBJDUMP_no_print_imm_hex, false);
+      InputArgs.hasFlag(OBJDUMP_print_imm_hex, OBJDUMP_no_print_imm_hex, true);
   PrivateHeaders = InputArgs.hasArg(OBJDUMP_private_headers);
   FilterSections = InputArgs.getAllArgValues(OBJDUMP_section_EQ);
   SectionHeaders = InputArgs.hasArg(OBJDUMP_section_headers);
   ShowAllSymbols = InputArgs.hasArg(OBJDUMP_show_all_symbols);
   ShowLMA = InputArgs.hasArg(OBJDUMP_show_lma);
   PrintSource = InputArgs.hasArg(OBJDUMP_source);
   parseIntArg(InputArgs, OBJDUMP_start_address_EQ, StartAddress);
   HasStartAddressFlag = InputArgs.hasArg(OBJDUMP_start_address_EQ);