MCParser/Debug info: Accept line number 0 as a legitimate value, since

CFE produces it to indicate artificial locations.
c.f.: DWARF standard, Table 6.2:
line -- An unsigned integer indicating a source line number. Lines are numbered beginning at 1. The compiler may emit the value 0 in cases where an instruction cannot be attributed to any source line.

llvm-svn: 191471

2 files changed, 3 insertions, 2 deletions

diff --git a/llvm/lib/MC/MCParser/AsmParser.cpp b/llvm/lib/MC/MCParser/AsmParser.cpp
index e36850beb82..9854b07a6c4 100644
--- a/llvm/lib/MC/MCParser/AsmParser.cpp
+++ b/llvm/lib/MC/MCParser/AsmParser.cpp
@@ -2634,8 +2634,8 @@ bool AsmParser::parseDirectiveLoc() {
   int64_t LineNumber = 0;
   if (getLexer().is(AsmToken::Integer)) {
     LineNumber = getTok().getIntVal();
-    if (LineNumber < 1)
-      return TokError("line number less than one in '.loc' directive");
+    if (LineNumber < 0)
+      return TokError("line number less than zero in '.loc' directive");
     Lex();
   }
 
diff --git a/llvm/test/MC/AsmParser/directive_loc.s b/llvm/test/MC/AsmParser/directive_loc.s
index 164d42a3fa7..700a32ca389 100644
--- a/llvm/test/MC/AsmParser/directive_loc.s
+++ b/llvm/test/MC/AsmParser/directive_loc.s
@@ -6,3 +6,4 @@
         .loc 1 2
         .loc 1 2 3
         .loc 1 2 discriminator 1
+        .loc 1 0