[ms] [llvm-ml] Accept /WX to signal that warnings should be fatal.

[epastor]

Summary

Define -fatal-warnings to make warnings fatal, and accept /WX as an ML.EXE compatible alias for it.

Also make sure that if Warning() returns true, we always treat it as an error.

[thakis]

Test?

[epastor]

Rebase on parent

[epastor]

Revised to include fatal warning support, and test both cases

[epastor]

Rebase to HEAD

llvm/lib/MC/MCParser/MasmParser.cpp

 bool MasmParser::parseDirectiveAlign() {
   SMLoc AlignmentLoc = getLexer().getLoc();
   int64_t Alignment;
 
   if (checkForValidSection())
     return addErrorSuffix(" in align directive");
   // Ignore empty 'align' directives.
   if (getTok().is(AsmToken::EndOfStatement)) {
-    Warning(AlignmentLoc, "align directive with no operand is ignored");
-    return parseToken(AsmToken::EndOfStatement);
+    return Warning(AlignmentLoc,
+                   "align directive with no operand is ignored") &&
+           parseToken(AsmToken::EndOfStatement);
   }
   if (parseAbsoluteExpression(Alignment) ||
       parseToken(AsmToken::EndOfStatement))
     return addErrorSuffix(" in align directive");
 
   // Always emit an alignment here even if we thrown an error.
   bool ReturnVal = false;
 

llvm/test/tools/llvm-ml/hexfloat_error.asm

+; RUN: not llvm-ml -filetype=s %s /WX /Fo /dev/null 2>&1 | FileCheck %s --implicit-check-not=error:
+
+.data
+
+; CHECK: :[[# @LINE + 1]]:25: error: MASM-style hex floats ignore explicit sign
+negative_hexfloat REAL4 -3fa66666r
+
+.code
+
+END

llvm/test/tools/llvm-ml/hexfloat_warn.asm

+; RUN: llvm-ml -filetype=s %s /Fo - 2>&1 | FileCheck %s
+
+.data
+
+; CHECK: :[[# @LINE + 1]]:25: warning: MASM-style hex floats ignore explicit sign
+negative_hexfloat REAL4 -3fa66666r
+; CHECK-LABEL: negative_hexfloat:
+; CHECK-NEXT: .long 1067869798
+
+.code
+
+END

llvm/tools/llvm-ml/Opts.td

class UnsupportedJoinedOrSeparate<string name> :
         JoinedOrSeparate<["/", "-"], name>, Group<unsupported_Group>;
 class UnsupportedSeparate<string name> : Separate<["/", "-"], name>,
                                          Group<unsupported_Group>;
 
 def bitness : LLVMJoined<"m">, Values<"32,64">,
               HelpText<"Target platform (x86 or x86-64)">;
 def as_lex : LLVMFlag<"as-lex">,
              HelpText<"Lex tokens from a .asm file without assembling">;
+def fatal_warnings : LLVMFlag<"fatal-warnings">,
+                     HelpText<"Treat warnings as errors">;
 def filetype : LLVMJoined<"filetype=">, Values<"obj,s,null">,
                HelpText<"Emit a file with the given type">;
 def output_att_asm : LLVMFlag<"output-att-asm">,
                      HelpText<"Use ATT syntax for output assembly">;
 def show_encoding : LLVMFlag<"show-encoding">,
                     HelpText<"Show instruction encodings in output assembly">;
 def show_inst : LLVMFlag<"show-inst">,
                 HelpText<"Show internal instruction representation in output "

 def safeseh : MLFlag<"safeseh">,
               HelpText<"Mark resulting object files as either containing no "
                        "exception handlers or containing exception handlers "
                        "that are all declared with .SAFESEH. Only available in "
                        "32-bit.">;
 def assembly_file : MLJoinedOrSeparate<"Ta">,
                     HelpText<"Assemble source file with name not ending with "
                              "the .asm extension">;
+def error_on_warning : MLFlag<"WX">, Alias<fatal_warnings>;
 def parse_only : MLFlag<"Zs">, HelpText<"Run a syntax-check only">,
                  Alias<filetype>, AliasArgs<["null"]>;
 
 def tiny_model_support : UnsupportedFlag<"AT">, HelpText<"">;
 def alternate_linker : UnsupportedJoined<"Bl">, HelpText<"">;
 def coff_object_file : UnsupportedFlag<"coff">, HelpText<"">;
 def preserve_identifier_case : UnsupportedFlag<"Cp">, HelpText<"">;
 def uppercase_identifiers : UnsupportedFlag<"Cu">, HelpText<"">;

 def listing_width : UnsupportedSeparate<"SI">, HelpText<"">;
 def listing_without_symbols : UnsupportedFlag<"Sn">, HelpText<"">;
 def listing_page_length : UnsupportedSeparate<"Sp">, HelpText<"">;
 def listing_subtitle : UnsupportedSeparate<"Ss">, HelpText<"">;
 def listing_title : UnsupportedSeparate<"St">, HelpText<"">;
 def listing_false_conditionals : UnsupportedFlag<"Sx">, HelpText<"">;
 def extra_warnings : UnsupportedFlag<"w">, HelpText<"">;
 def warning_level : UnsupportedJoined<"W">, HelpText<"">;
-def error_on_warning : UnsupportedFlag<"WX">, HelpText<"">;
 def ignore_include_envvar : UnsupportedFlag<"X">, HelpText<"">;
 def line_number_info : UnsupportedFlag<"Zd">, HelpText<"">;
 def export_all_symbols : UnsupportedFlag<"Zf">, HelpText<"">;
 def codeview_info : UnsupportedFlag<"Zi">, HelpText<"">;
 def enable_m510_option : UnsupportedFlag<"Zm">, HelpText<"">;
 def structure_packing : UnsupportedJoined<"Zp">, HelpText<"">;

llvm/tools/llvm-ml/llvm-ml.cpp

if (InputArgs.hasArg(OPT_help)) {
     outs() << "USAGE: " << ProgName << " [ /options ] file\n"
            << "Run \"" << ProgName << " /?\" or \"" << ProgName
            << " /help\" for more info.\n";
     return 0;
   }
 
   MCTargetOptions MCOptions;
   MCOptions.AssemblyLanguage = "masm";
+  MCOptions.MCFatalWarnings = InputArgs.hasArg(OPT_fatal_warnings);
 
   Triple TheTriple = GetTriple(ProgName, InputArgs);
   std::string Error;
   const Target *TheTarget = TargetRegistry::lookupTarget("", TheTriple, Error);
   if (!TheTarget) {
     WithColor::error(errs(), ProgName) << Error;
     return 1;
   }