First bit of support for the dwarf .loc directive. This patch updates the

needed parsing for the .loc directive and saves the current info from that
into the context.  The next patch will take the current loc info after an
instruction is assembled and save that info into a vector for each section for
use to build the line number tables.  The patch after that will encode the info
from those vectors into the output file as the dwarf line tables.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@111956 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 97 insertions, 19 deletions

diff --git a/lib/MC/MCContext.cpp b/lib/MC/MCContext.cpp
index adf476cf3f..13cf9a8048 100644
--- a/lib/MC/MCContext.cpp
+++ b/lib/MC/MCContext.cpp
@@ -24,7 +24,8 @@ typedef StringMap<const MCSectionELF*> ELFUniqueMapTy;
 typedef StringMap<const MCSectionCOFF*> COFFUniqueMapTy;
 
 
-MCContext::MCContext(const MCAsmInfo &mai) : MAI(mai), NextUniqueID(0) {
+MCContext::MCContext(const MCAsmInfo &mai) : MAI(mai), NextUniqueID(0),
+                     CurrentDwarfLoc(0,0,0,0,0) {
   MachOUniquingMap = 0;
   ELFUniquingMap = 0;
   COFFUniquingMap = 0;
@@ -32,6 +33,8 @@ MCContext::MCContext(const MCAsmInfo &mai) : MAI(mai), NextUniqueID(0) {
   SecureLogFile = getenv("AS_SECURE_LOG_FILE");
   SecureLog = 0;
   SecureLogUsed = false;
+
+  DwarfLocSeen = false;
 }
 
 MCContext::~MCContext() {
@@ -247,3 +250,16 @@ unsigned MCContext::GetDwarfFile(StringRef FileName, unsigned FileNumber) {
   // return the allocated FileNumber.
   return FileNumber;
 }
+
+/// ValidateDwarfFileNumber - takes a dwarf file number and returns true if it
+/// currently is assigned and false otherwise.
+bool MCContext::ValidateDwarfFileNumber(unsigned FileNumber) {
+  if(FileNumber == 0 || FileNumber >= MCDwarfFiles.size())
+    return false;
+
+  MCDwarfFile *&ExistingFile = MCDwarfFiles[FileNumber];
+  if (ExistingFile)
+    return true;
+  else
+    return false;
+}
diff --git a/lib/MC/MCParser/AsmParser.cpp b/lib/MC/MCParser/AsmParser.cpp
index 747b0097e1..c65becf974 100644
--- a/lib/MC/MCParser/AsmParser.cpp
+++ b/lib/MC/MCParser/AsmParser.cpp
@@ -1838,39 +1838,101 @@ bool GenericAsmParser::ParseDirectiveLine(StringRef, SMLoc DirectiveLoc) {
 
 
 /// ParseDirectiveLoc
-/// ::= .loc number [number [number]]
+/// ::= .loc FileNumber LineNumber [ColumnPos] [basic_block] [prologue_end]
+///                                [epilogue_begin] [is_stmt VALUE] [isa VALUE]
+/// The first number is a file number, must have been previously assigned with
+/// a .file directive, the second number is the line number and optionally the
+/// third number is a column position (zero if not specified).  The remaining
+/// optional items are .loc sub-directives.
 bool GenericAsmParser::ParseDirectiveLoc(StringRef, SMLoc DirectiveLoc) {
+
   if (getLexer().isNot(AsmToken::Integer))
     return TokError("unexpected token in '.loc' directive");
-
-  // FIXME: What are these fields?
   int64_t FileNumber = getTok().getIntVal();
-  (void) FileNumber;
-  // FIXME: Validate file.
+  if (FileNumber < 1)
+    return TokError("file number less than one in '.loc' directive");
+  if (!getContext().ValidateDwarfFileNumber(FileNumber))
+    return TokError("unassigned file number in '.loc' directive");
+  Lex();
 
+  if (getLexer().isNot(AsmToken::Integer))
+    return TokError("unexpected token in '.loc' directive");
+  int64_t LineNumber = getTok().getIntVal();
+  if (LineNumber < 1)
+    return TokError("line number less than one in '.loc' directive");
   Lex();
-  if (getLexer().isNot(AsmToken::EndOfStatement)) {
-    if (getLexer().isNot(AsmToken::Integer))
-      return TokError("unexpected token in '.loc' directive");
 
-    int64_t Param2 = getTok().getIntVal();
-    (void) Param2;
+  int64_t ColumnPos = 0;
+  if (getLexer().is(AsmToken::Integer)) {
+    ColumnPos = getTok().getIntVal();
+    if (ColumnPos < 0)
+      return TokError("column position less than zero in '.loc' directive");
     Lex();
+  }
 
-    if (getLexer().isNot(AsmToken::EndOfStatement)) {
-      if (getLexer().isNot(AsmToken::Integer))
+  unsigned Flags = 0;
+  unsigned Isa = 0;
+  if (getLexer().isNot(AsmToken::EndOfStatement)) {
+    for (;;) {
+      if (getLexer().is(AsmToken::EndOfStatement))
+        break;
+
+      StringRef Name;
+      SMLoc Loc = getTok().getLoc();
+      if (getParser().ParseIdentifier(Name))
         return TokError("unexpected token in '.loc' directive");
 
-      int64_t Param3 = getTok().getIntVal();
-      (void) Param3;
-      Lex();
+      if (Name == "basic_block")
+        Flags |= DWARF2_FLAG_BASIC_BLOCK;
+      else if (Name == "prologue_end")
+        Flags |= DWARF2_FLAG_PROLOGUE_END;
+      else if (Name == "epilogue_begin")
+        Flags |= DWARF2_FLAG_EPILOGUE_BEGIN;
+      else if (Name == "is_stmt") {
+        SMLoc Loc = getTok().getLoc();
+        const MCExpr *Value;
+        if (getParser().ParseExpression(Value))
+          return true;
+        // The expression must be the constant 0 or 1.
+        if (const MCConstantExpr *MCE = dyn_cast<MCConstantExpr>(Value)) {
+          int Value = MCE->getValue();
+          if (Value == 0)
+            Flags &= ~DWARF2_FLAG_IS_STMT;
+          else if (Value == 1)
+            Flags |= DWARF2_FLAG_IS_STMT;
+          else
+            return Error(Loc, "is_stmt value not 0 or 1");
+	}
+        else {
+          return Error(Loc, "is_stmt value not the constant value of 0 or 1");
+        }
+      }
+      else if (Name == "isa") {
+        SMLoc Loc = getTok().getLoc();
+        const MCExpr *Value;
+        if (getParser().ParseExpression(Value))
+          return true;
+        // The expression must be a constant greater or equal to 0.
+        if (const MCConstantExpr *MCE = dyn_cast<MCConstantExpr>(Value)) {
+          int Value = MCE->getValue();
+          if (Value < 0)
+            return Error(Loc, "isa number less than zero");
+          Isa = Value;
+	}
+        else {
+          return Error(Loc, "isa number not a constant value");
+        }
+      }
+      else {
+        return Error(Loc, "unknown sub-directive in '.loc' directive");
+      }
 
-      // FIXME: Do something with the .loc.
+      if (getLexer().is(AsmToken::EndOfStatement))
+        break;
     }
   }
 
-  if (getLexer().isNot(AsmToken::EndOfStatement))
-    return TokError("unexpected token in '.file' directive");
+  getContext().setCurrentDwarfLoc(FileNumber, LineNumber, ColumnPos, Flags,Isa);
 
   return false;
 }