[mlir][spirv] Add `const` qualifier for static arrays

[antiagainst]

Summary

This makes the local variable implies to have the correct
type to satisfy ArrayRef's constructor:

/*implicit*/ constexpr ArrayRef(const T (&Arr)[N])

Hopefully this should please GCC 5.

[merge_guards_bot]

Unit tests: pass. 61955 tests passed, 0 failed and 783 were skipped.

clang-tidy: unknown.

clang-format: pass.

Build artifacts: diff.json, clang-format.patch, CMakeCache.txt, console-log.txt, test-results.xml

[ftynse]

I think you can push fixes for upstream breakages, especially in the part you own, without pre-review.

[antiagainst]

In D72924#1826648, @ftynse wrote:

I think you can push fixes for upstream breakages, especially in the part you own, without pre-review.

Oh, that's good to know. Thanks for the info!

[ftynse]

https://llvm.org/docs/DeveloperPolicy.html#code-reviews point 3

Code can be reviewed either before it is committed or after. We expect major changes to be reviewed before being committed, but smaller changes (or changes where the developer owns the component) can be reviewed after commit.

mlir/lib/Dialect/SPIRV/SPIRVLowering.cpp

for (const auto &ors : caps)
           })) {
         LLVM_DEBUG(llvm::dbgs() << op->getName()
                                 << " illegal: missing required capability\n");
         return false;
       }
   }
 
   return true;
-};
+}

mlir/tools/mlir-tblgen/SPIRVUtilsGen.cpp

os << "ArrayRef<Capability> "
      << "  switch (cap) {\n"
      << "  default: return {};\n";
   for (const EnumAttrCase &enumerant : enumAttr.getAllCases()) {
     const Record &def = enumerant.getDef();
     if (!def.getValue("implies"))
       continue;
 
     os << "  case Capability::" << enumerant.getSymbol()
-       << ": {static Capability implies[] = {";
+       << ": {static const Capability implies[] = {";
     std::vector<Record *> impliedCapsDefs = def.getValueAsListOfDefs("implies");
     mlir::interleaveComma(impliedCapsDefs, os, [&](const Record *capDef) {
       os << "Capability::" << EnumAttrCase(capDef).getSymbol();
     });
     os << "}; return implies; }\n";
   }
   os << "  }\n";
   os << "}\n";