[CodeView] Use assembler directives for line tables

Adds a new family of .cv_* directives to LLVM's variant of GAS syntax:

- .cv_file: Similar to DWARF .file directives

- .cv_loc: Similar to the DWARF .loc directive, but starts with a
  function id. CodeView line tables are emitted by function instead of
  by compilation unit, so we needed an extra field to communicate this.
  Rather than overloading the .loc direction further, we decided it was
  better to have our own directive.

- .cv_stringtable: Emits the codeview string table at the current
  position. Currently this just contains the filenames as
  null-terminated strings.

- .cv_filechecksums: Emits the file checksum table for all files used
  with .cv_file so far. There is currently no support for emitting
  actual checksums, just filenames.

This moves the line table emission code down into the assembler.  This
is in preparation for implementing the inlined call site line table
format. The inline line table format encoding algorithm requires knowing
the absolute code offsets, so it must run after the assembler has laid
out the code.

David Majnemer collaborated on this patch.

llvm-svn: 259117

1 files changed, 174 insertions, 0 deletions

diff --git a/llvm/lib/MC/MCParser/AsmParser.cpp b/llvm/lib/MC/MCParser/AsmParser.cpp
index b1814f8c8ff..360de5db883 100644
--- a/llvm/lib/MC/MCParser/AsmParser.cpp
+++ b/llvm/lib/MC/MCParser/AsmParser.cpp
@@ -357,6 +357,8 @@ private:
     DK_IFNB, DK_IFC, DK_IFEQS, DK_IFNC, DK_IFNES, DK_IFDEF, DK_IFNDEF,
     DK_IFNOTDEF, DK_ELSEIF, DK_ELSE, DK_ENDIF,
     DK_SPACE, DK_SKIP, DK_FILE, DK_LINE, DK_LOC, DK_STABS,
+    DK_CV_FILE, DK_CV_LOC, DK_CV_LINETABLE, DK_CV_STRINGTABLE,
+    DK_CV_FILECHECKSUMS,
     DK_CFI_SECTIONS, DK_CFI_STARTPROC, DK_CFI_ENDPROC, DK_CFI_DEF_CFA,
     DK_CFI_DEF_CFA_OFFSET, DK_CFI_ADJUST_CFA_OFFSET, DK_CFI_DEF_CFA_REGISTER,
     DK_CFI_OFFSET, DK_CFI_REL_OFFSET, DK_CFI_PERSONALITY, DK_CFI_LSDA,
@@ -394,6 +396,13 @@ private:
   bool parseDirectiveLoc();
   bool parseDirectiveStabs();
 
+  // ".cv_file", ".cv_loc", ".cv_linetable"
+  bool parseDirectiveCVFile();
+  bool parseDirectiveCVLoc();
+  bool parseDirectiveCVLinetable();
+  bool parseDirectiveCVStringTable();
+  bool parseDirectiveCVFileChecksums();
+
   // .cfi directives
   bool parseDirectiveCFIRegister(SMLoc DirectiveLoc);
   bool parseDirectiveCFIWindowSave();
@@ -1638,6 +1647,16 @@ bool AsmParser::parseStatement(ParseStatementInfo &Info,
       return parseDirectiveLoc();
     case DK_STABS:
       return parseDirectiveStabs();
+    case DK_CV_FILE:
+      return parseDirectiveCVFile();
+    case DK_CV_LOC:
+      return parseDirectiveCVLoc();
+    case DK_CV_LINETABLE:
+      return parseDirectiveCVLinetable();
+    case DK_CV_STRINGTABLE:
+      return parseDirectiveCVStringTable();
+    case DK_CV_FILECHECKSUMS:
+      return parseDirectiveCVFileChecksums();
     case DK_CFI_SECTIONS:
       return parseDirectiveCFISections();
     case DK_CFI_STARTPROC:
@@ -3070,6 +3089,156 @@ bool AsmParser::parseDirectiveStabs() {
   return TokError("unsupported directive '.stabs'");
 }
 
+/// parseDirectiveCVFile
+/// ::= .cv_file number filename
+bool AsmParser::parseDirectiveCVFile() {
+  SMLoc FileNumberLoc = getLexer().getLoc();
+  if (getLexer().isNot(AsmToken::Integer))
+    return TokError("expected file number in '.cv_file' directive");
+
+  int64_t FileNumber = getTok().getIntVal();
+  Lex();
+
+  if (FileNumber < 1)
+    return TokError("file number less than one");
+
+  if (getLexer().isNot(AsmToken::String))
+    return TokError("unexpected token in '.cv_file' directive");
+
+  // Usually the directory and filename together, otherwise just the directory.
+  // Allow the strings to have escaped octal character sequence.
+  std::string Filename;
+  if (parseEscapedString(Filename))
+    return true;
+  Lex();
+
+  if (getLexer().isNot(AsmToken::EndOfStatement))
+    return TokError("unexpected token in '.cv_file' directive");
+
+  if (getStreamer().EmitCVFileDirective(FileNumber, Filename) == 0)
+    Error(FileNumberLoc, "file number already allocated");
+
+  return false;
+}
+
+/// parseDirectiveCVLoc
+/// ::= .cv_loc FunctionId FileNumber [LineNumber] [ColumnPos] [prologue_end]
+///                                [is_stmt 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 AsmParser::parseDirectiveCVLoc() {
+  if (getLexer().isNot(AsmToken::Integer))
+    return TokError("unexpected token in '.cv_loc' directive");
+
+  int64_t FunctionId = getTok().getIntVal();
+  if (FunctionId < 0)
+    return TokError("function id less than zero in '.cv_loc' directive");
+  Lex();
+
+  int64_t FileNumber = getTok().getIntVal();
+  if (FileNumber < 1)
+    return TokError("file number less than one in '.cv_loc' directive");
+  if (!getContext().isValidCVFileNumber(FileNumber))
+    return TokError("unassigned file number in '.cv_loc' directive");
+  Lex();
+
+  int64_t LineNumber = 0;
+  if (getLexer().is(AsmToken::Integer)) {
+    LineNumber = getTok().getIntVal();
+    if (LineNumber < 0)
+      return TokError("line number less than zero in '.cv_loc' directive");
+    Lex();
+  }
+
+  int64_t ColumnPos = 0;
+  if (getLexer().is(AsmToken::Integer)) {
+    ColumnPos = getTok().getIntVal();
+    if (ColumnPos < 0)
+      return TokError("column position less than zero in '.cv_loc' directive");
+    Lex();
+  }
+
+  bool PrologueEnd = false;
+  uint64_t IsStmt = 0;
+  while (getLexer().isNot(AsmToken::EndOfStatement)) {
+    StringRef Name;
+    SMLoc Loc = getTok().getLoc();
+    if (parseIdentifier(Name))
+      return TokError("unexpected token in '.cv_loc' directive");
+
+    if (Name == "prologue_end")
+      PrologueEnd = true;
+    else if (Name == "is_stmt") {
+      Loc = getTok().getLoc();
+      const MCExpr *Value;
+      if (parseExpression(Value))
+        return true;
+      // The expression must be the constant 0 or 1.
+      IsStmt = ~0ULL;
+      if (const auto *MCE = dyn_cast<MCConstantExpr>(Value))
+        IsStmt = MCE->getValue();
+
+      if (IsStmt > 1)
+        return Error(Loc, "is_stmt value not 0 or 1");
+    } else {
+      return Error(Loc, "unknown sub-directive in '.cv_loc' directive");
+    }
+  }
+
+  getStreamer().EmitCVLocDirective(FunctionId, FileNumber, LineNumber,
+                                   ColumnPos, PrologueEnd, IsStmt, StringRef());
+  return false;
+}
+
+/// parseDirectiveCVLinetable
+/// ::= .cv_linetable FunctionId, FnStart, FnEnd
+bool AsmParser::parseDirectiveCVLinetable() {
+  int64_t FunctionId = getTok().getIntVal();
+  if (FunctionId < 0)
+    return TokError("function id less than zero in '.cv_linetable' directive");
+  Lex();
+
+  if (Lexer.isNot(AsmToken::Comma))
+    return TokError("unexpected token in '.cv_linetable' directive");
+  Lex();
+
+  SMLoc Loc = getLexer().getLoc();
+  StringRef FnStartName;
+  if (parseIdentifier(FnStartName))
+    return Error(Loc, "expected identifier in directive");
+
+  if (Lexer.isNot(AsmToken::Comma))
+    return TokError("unexpected token in '.cv_linetable' directive");
+  Lex();
+
+  Loc = getLexer().getLoc();
+  StringRef FnEndName;
+  if (parseIdentifier(FnEndName))
+    return Error(Loc, "expected identifier in directive");
+
+  MCSymbol *FnStartSym = getContext().getOrCreateSymbol(FnStartName);
+  MCSymbol *FnEndSym = getContext().getOrCreateSymbol(FnEndName);
+
+  getStreamer().EmitCVLinetableDirective(FunctionId, FnStartSym, FnEndSym);
+  return false;
+}
+
+/// parseDirectiveCVStringTable
+/// ::= .cv_stringtable
+bool AsmParser::parseDirectiveCVStringTable() {
+  getStreamer().EmitCVStringTableDirective();
+  return false;
+}
+
+/// parseDirectiveCVFileChecksums
+/// ::= .cv_filechecksums
+bool AsmParser::parseDirectiveCVFileChecksums() {
+  getStreamer().EmitCVFileChecksumsDirective();
+  return false;
+}
+
 /// parseDirectiveCFISections
 /// ::= .cfi_sections section [, section]
 bool AsmParser::parseDirectiveCFISections() {
@@ -4381,6 +4550,11 @@ void AsmParser::initializeDirectiveKindMap() {
   DirectiveKindMap[".line"] = DK_LINE;
   DirectiveKindMap[".loc"] = DK_LOC;
   DirectiveKindMap[".stabs"] = DK_STABS;
+  DirectiveKindMap[".cv_file"] = DK_CV_FILE;
+  DirectiveKindMap[".cv_loc"] = DK_CV_LOC;
+  DirectiveKindMap[".cv_linetable"] = DK_CV_LINETABLE;
+  DirectiveKindMap[".cv_stringtable"] = DK_CV_STRINGTABLE;
+  DirectiveKindMap[".cv_filechecksums"] = DK_CV_FILECHECKSUMS;
   DirectiveKindMap[".sleb128"] = DK_SLEB128;
   DirectiveKindMap[".uleb128"] = DK_ULEB128;
   DirectiveKindMap[".cfi_sections"] = DK_CFI_SECTIONS;