[llvm] [NFC][LLVM] Pass/return SMLoc by value instead of const reference (PR #160797)

[Aaron Puchert via llvm-commits]

aaronpuchert wrote:

Could this have caused the failure in https://lab.llvm.org/buildbot/#/builders/27/builds/16657?

```
FAILED: lib/Target/M68k/AsmParser/CMakeFiles/LLVMM68kAsmParser.dir/M68kAsmParser.cpp.o 
/usr/bin/c++ -DGTEST_HAS_RTTI=0 -D_DEBUG -D_GLIBCXX_ASSERTIONS -D_GLIBCXX_USE_CXX11_ABI=1 -D_GNU_SOURCE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -I/var/lib/buildbot/workers/suse-gary-m68k-cross/clang-m68k-linux-cross/stage1/lib/Target/M68k/AsmParser -I/var/lib/buildbot/workers/suse-gary-m68k-cross/clang-m68k-linux-cross/llvm/llvm/lib/Target/M68k/AsmParser -I/var/lib/buildbot/workers/suse-gary-m68k-cross/clang-m68k-linux-cross/llvm/llvm/lib/Target/M68k -I/var/lib/buildbot/workers/suse-gary-m68k-cross/clang-m68k-linux-cross/stage1/lib/Target/M68k -I/var/lib/buildbot/workers/suse-gary-m68k-cross/clang-m68k-linux-cross/stage1/include -I/var/lib/buildbot/workers/suse-gary-m68k-cross/clang-m68k-linux-cross/llvm/llvm/include -fPIC -fno-semantic-interposition -fvisibility-inlines-hidden -Werror=date-time -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wno-missing-field-initializers -pedantic -Wno-long-long -Wimplicit-fallthrough -Wno-uninitialized -Wno-nonnull -Wno-class-memaccess -Wno-dangling-reference -Wno-redundant-move -Wno-pessimizing-move -Wno-array-bounds -Wno-stringop-overread -Wno-noexcept-type -Wdelete-non-virtual-dtor -Wsuggest-override -Wno-comment -Wno-misleading-indentation -Wctad-maybe-unsupported -fdiagnostics-color -ffunction-sections -fdata-sections -O3 -DNDEBUG -std=c++17 -fvisibility=hidden  -fno-exceptions -funwind-tables -fno-rtti -UNDEBUG -MD -MT lib/Target/M68k/AsmParser/CMakeFiles/LLVMM68kAsmParser.dir/M68kAsmParser.cpp.o -MF lib/Target/M68k/AsmParser/CMakeFiles/LLVMM68kAsmParser.dir/M68kAsmParser.cpp.o.d -o lib/Target/M68k/AsmParser/CMakeFiles/LLVMM68kAsmParser.dir/M68kAsmParser.cpp.o -c /var/lib/buildbot/workers/suse-gary-m68k-cross/clang-m68k-linux-cross/llvm/llvm/lib/Target/M68k/AsmParser/M68kAsmParser.cpp
/var/lib/buildbot/workers/suse-gary-m68k-cross/clang-m68k-linux-cross/llvm/llvm/lib/Target/M68k/AsmParser/M68kAsmParser.cpp:994:6: error: no declaration matches ‘bool {anonymous}::M68kAsmParser::invalidOperand(const llvm::SMLoc&, const llvm::OperandVector&, const uint64_t&)’
  994 | bool M68kAsmParser::invalidOperand(SMLoc const &Loc,
      |      ^~~~~~~~~~~~~
/var/lib/buildbot/workers/suse-gary-m68k-cross/clang-m68k-linux-cross/llvm/llvm/lib/Target/M68k/AsmParser/M68kAsmParser.cpp:42:8: note: candidate is: ‘bool {anonymous}::M68kAsmParser::invalidOperand(llvm::SMLoc, const llvm::OperandVector&, const uint64_t&)’
   42 |   bool invalidOperand(SMLoc Loc, const OperandVector &Operands,
      |        ^~~~~~~~~~~~~~
/var/lib/buildbot/workers/suse-gary-m68k-cross/clang-m68k-linux-cross/llvm/llvm/lib/Target/M68k/AsmParser/M68kAsmParser.cpp:34:7: note: ‘class {anonymous}::M68kAsmParser’ defined here
   34 | class M68kAsmParser : public MCTargetAsmParser {
      |       ^~~~~~~~~~~~~
/var/lib/buildbot/workers/suse-gary-m68k-cross/clang-m68k-linux-cross/llvm/llvm/lib/Target/M68k/AsmParser/M68kAsmParser.cpp:1018:6: error: no declaration matches ‘bool {anonymous}::M68kAsmParser::missingFeature(const llvm::SMLoc&, const uint64_t&)’
 1018 | bool M68kAsmParser::missingFeature(llvm::SMLoc const &Loc,
      |      ^~~~~~~~~~~~~
/var/lib/buildbot/workers/suse-gary-m68k-cross/clang-m68k-linux-cross/llvm/llvm/lib/Target/M68k/AsmParser/M68kAsmParser.cpp:44:8: note: candidate is: ‘bool {anonymous}::M68kAsmParser::missingFeature(llvm::SMLoc, const uint64_t&)’
   44 |   bool missingFeature(SMLoc Loc, const uint64_t &ErrorInfo);
      |        ^~~~~~~~~~~~~~
/var/lib/buildbot/workers/suse-gary-m68k-cross/clang-m68k-linux-cross/llvm/llvm/lib/Target/M68k/AsmParser/M68kAsmParser.cpp:34:7: note: ‘class {anonymous}::M68kAsmParser’ defined here
   34 | class M68kAsmParser : public MCTargetAsmParser {
      |       ^~~~~~~~~~~~~
/var/lib/buildbot/workers/suse-gary-m68k-cross/clang-m68k-linux-cross/llvm/llvm/lib/Target/M68k/AsmParser/M68kAsmParser.cpp:42:8: warning: ‘bool {anonymous}::M68kAsmParser::invalidOperand(llvm::SMLoc, const llvm::OperandVector&, const uint64_t&)’ used but never defined
   42 |   bool invalidOperand(SMLoc Loc, const OperandVector &Operands,
      |        ^~~~~~~~~~~~~~
/var/lib/buildbot/workers/suse-gary-m68k-cross/clang-m68k-linux-cross/llvm/llvm/lib/Target/M68k/AsmParser/M68kAsmParser.cpp:44:8: warning: ‘bool {anonymous}::M68kAsmParser::missingFeature(llvm::SMLoc, const uint64_t&)’ used but never defined
   44 |   bool missingFeature(SMLoc Loc, const uint64_t &ErrorInfo);
      |        ^~~~~~~~~~~~~~
```

https://github.com/llvm/llvm-project/pull/160797