[MC] Support .dc directives in assembler parser

[phosek]

Summary

While these directives are mostly aliases for the existing integer and float value directives, some of them like .dc.a have no direct equivalents and are sometimes being used for convenience.

[echristo]

Hey, thanks!

This has been on my todo list for a while.

-eric

[phosek]

No problem, I'm thinking about adding support for .dcb and .ds as a follow up change unless you've already started working on those.

[echristo]

In D23810#523381, @phosek wrote:

No problem, I'm thinking about adding support for .dcb and .ds as a follow up change unless you've already started working on those.

I haven't so please do feel free :)

lib/MC/MCParser/AsmParser.cpp

private:
   bool parseRegisterOrRegisterNumber(int64_t &Register, SMLoc DirectiveLoc);
 
   // Generic (target and platform independent) directive parsing.
   enum DirectiveKind {
     DK_NO_DIRECTIVE, // Placeholder
     DK_SET, DK_EQU, DK_EQUIV, DK_ASCII, DK_ASCIZ, DK_STRING, DK_BYTE, DK_SHORT,
     DK_RELOC,
     DK_VALUE, DK_2BYTE, DK_LONG, DK_INT, DK_4BYTE, DK_QUAD, DK_8BYTE, DK_OCTA,
+    DK_DC, DK_DC_A, DK_DC_B, DK_DC_D, DK_DC_L, DK_DC_S, DK_DC_W, DK_DC_X,
     DK_SINGLE, DK_FLOAT, DK_DOUBLE, DK_ALIGN, DK_ALIGN32, DK_BALIGN, DK_BALIGNW,
     DK_BALIGNL, DK_P2ALIGN, DK_P2ALIGNW, DK_P2ALIGNL, DK_ORG, DK_FILL, DK_ENDR,
     DK_BUNDLE_ALIGN_MODE, DK_BUNDLE_LOCK, DK_BUNDLE_UNLOCK,
     DK_ZERO, DK_EXTERN, DK_GLOBL, DK_GLOBAL,
     DK_LAZY_REFERENCE, DK_NO_DEAD_STRIP, DK_SYMBOL_RESOLVER,
     DK_PRIVATE_EXTERN, DK_REFERENCE, DK_WEAK_DEFINITION, DK_WEAK_REFERENCE,
     DK_WEAK_DEF_CAN_BE_HIDDEN, DK_COMM, DK_COMMON, DK_LCOMM, DK_ABORT,
     DK_INCLUDE, DK_INCBIN, DK_CODE16, DK_CODE16GCC, DK_REPT, DK_IRP, DK_IRPC,
if (IDVal[0] == '.' && IDVal != ".") {
     case DK_ERR:
       return parseDirectiveError(IDLoc, false);
     case DK_ERROR:
       return parseDirectiveError(IDLoc, true);
     case DK_WARNING:
       return parseDirectiveWarning(IDLoc);
     case DK_RELOC:
       return parseDirectiveReloc(IDLoc);
+    case DK_DC:
+      return parseDirectiveValue(2);
+    case DK_DC_A:
+      return parseDirectiveValue(getContext().getAsmInfo()->getPointerSize());
+    case DK_DC_B:
+      return parseDirectiveValue(1);
+    case DK_DC_D:
+      return parseDirectiveRealValue(APFloat::IEEEdouble);
+    case DK_DC_L:
+      return parseDirectiveValue(4);
+    case DK_DC_S:
+      return parseDirectiveRealValue(APFloat::IEEEsingle);
+    case DK_DC_W:
+      return parseDirectiveValue(2);
+    case DK_DC_X:
+      return TokError(Twine(IDVal) +
+                      " not currently supported for this target");
     }
 
     return Error(IDLoc, "unknown directive");
   }
 
   // __asm _emit or __asm __emit
   if (ParsingInlineAsm && (IDVal == "_emit" || IDVal == "__emit" ||
                            IDVal == "_EMIT" || IDVal == "__EMIT"))
void AsmParser::initializeDirectiveKindMap() {
   DirectiveKindMap[".exitm"] = DK_EXITM;
   DirectiveKindMap[".endm"] = DK_ENDM;
   DirectiveKindMap[".endmacro"] = DK_ENDMACRO;
   DirectiveKindMap[".purgem"] = DK_PURGEM;
   DirectiveKindMap[".err"] = DK_ERR;
   DirectiveKindMap[".error"] = DK_ERROR;
   DirectiveKindMap[".warning"] = DK_WARNING;
   DirectiveKindMap[".reloc"] = DK_RELOC;
+  DirectiveKindMap[".dc"] = DK_DC;
+  DirectiveKindMap[".dc.a"] = DK_DC_A;
+  DirectiveKindMap[".dc.b"] = DK_DC_B;
+  DirectiveKindMap[".dc.d"] = DK_DC_D;
+  DirectiveKindMap[".dc.l"] = DK_DC_L;
+  DirectiveKindMap[".dc.s"] = DK_DC_S;
+  DirectiveKindMap[".dc.w"] = DK_DC_W;
+  DirectiveKindMap[".dc.x"] = DK_DC_X;
 }
 
 MCAsmMacro *AsmParser::parseMacroLikeBody(SMLoc DirectiveLoc) {
   AsmToken EndToken, StartToken = getTok();
 
   unsigned NestLevel = 0;
   for (;;) {
     // Check whether we have reached the end of the file.

test/MC/AsmParser/directive_dc.s

+# RUN: not llvm-mc -triple i386-unknown-unknown %s | FileCheck %s
+# RUN: not llvm-mc -triple i386-unknown-unknown %s 2>&1 > /dev/null| FileCheck %s --check-prefix=CHECK-ERROR
+
+# CHECK: TEST0:
+# CHECK: .byte 0
+TEST0:
+        .dc.b 0
+
+# CHECK: TEST1:
+# CHECK: .short 3
+TEST1:
+        .dc 3
+
+# CHECK: TEST2:
+# CHECK: .short 3
+TEST2:
+        .dc.w 3
+
+# CHECK: TEST3:
+# CHECK: .long 8
+TEST3:
+        .dc.l 8
+
+# CHECK: TEST4:
+# CHECK: .long 8
+TEST4:
+        .dc.a 8
+
+# CHECK: TEST5
+# CHECK: .long  1067412619
+TEST5:
+        .dc.s 1.2455
+
+# CHECK: TEST6
+# CHECK: .quad  4597526701198935065
+TEST6:
+        .dc.d .232
+
+# CHECK-ERROR: error: .dc.x not currently supported for this target
+TEST7:
+        .dc.x 1.2e3