Redesign this to avoid standard stream classes. This stream class

provides pretty -printing of comments and other such things in asm
files.

llvm-svn: 75202

include/llvm/CodeGen/AsmStream.h

@@ -0,0 +1,179 @@
+//===-- llvm/CodeGen/AsmStream.h - AsmStream Framework --------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file was developed by the LLVM research group and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file contains raw_ostream implementations for ASM printers to
+// do things like pretty-print comments.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CODEGEN_ASMSTREAM_H
+#define LLVM_CODEGEN_ASMSTREAM_H
+
+#include "llvm/Target/TargetAsmInfo.h"
+#include <llvm/Support/raw_ostream.h>
+
+namespace llvm 
+{
+  /// raw_asm_fd_ostream - Formatted raw_fd_ostream to handle
+  /// asm-specific constructs
+  ///
+  class raw_asm_fd_ostream : public raw_fd_ostream {
+  private:
+    bool formatted;
+    int column;
+
+  protected:
+    void ComputeColumn(void) {
+      if (formatted) {
+        // Keep track of the current column by scanning the string for
+        // special characters
+
+        // Find the last newline.  This is our column start.  If there
+        // is no newline, start with the current column.
+        char *nlpos = NULL;        
+        for (char *pos = CurBufPtr(), *epos = StartBufPtr(); pos > epos; --pos) {
+          if (*(pos-1) == '\n') {
+            nlpos = pos-1;
+            // The newline will be counted, setting this to zero.  We
+            // need to do it this way in case nlpos is CurBufPtr().
+            column = -1;
+            break;
+          }
+        }
+
+        if (nlpos == NULL) {
+          nlpos = StartBufPtr();
+        }
+
+        // Walk through looking for tabs and advance column as appropriate
+        for (char *pos = nlpos, *epos = CurBufPtr(); pos != epos; ++pos) {
+          ++column;
+          if (*pos == '\t') {
+            // Advance to next tab stop (every eight characters)
+            column += ((8 - (column & 0x7)) & 0x7);
+            assert(!(column & 0x3) && "Column out of alignment");
+          }
+        }
+      }
+    }
+
+    virtual void AboutToFlush(void) {
+      ComputeColumn();
+    }
+
+  public:
+    /// raw_asm_fd_ostream - Open the specified file for writing. If
+    /// an error occurs, information about the error is put into
+    /// ErrorInfo, and the stream should be immediately destroyed; the
+    /// string will be empty if no error occurred.
+    ///
+    /// \param Filename - The file to open. If this is "-" then the
+    /// stream will use stdout instead.
+    /// \param Binary - The file should be opened in binary mode on
+    /// platforms that support this distinction.
+    raw_asm_fd_ostream(const char *Filename, bool Binary, std::string &ErrorInfo) 
+        : raw_fd_ostream(Filename, Binary, ErrorInfo),
+            formatted(!Binary), column(0) {}
+
+    /// raw_asm_fd_ostream ctor - FD is the file descriptor that this
+    /// writes to.  If ShouldClose is true, this closes the file when
+    /// the stream is destroyed.
+    raw_asm_fd_ostream(int fd, bool shouldClose, 
+                       bool unbuffered=false)
+        : raw_fd_ostream(fd, shouldClose, unbuffered),
+            formatted(true), column(0) {
+      if (unbuffered) {
+        assert(0 && "asm stream must be buffered");
+        // Force buffering
+        SetBufferSize();
+      }
+    }
+
+
+    /// SetColumn - Align the output to some column number
+    ///
+    void setColumn(int newcol, int minpad = 0) {
+      if (formatted) {
+        flush();
+
+        // Output spaces until we reach the desired column
+        int num = newcol - column;
+        if (num <= 0) {
+          num = minpad;
+        }
+
+        // TODO: Write a whole string at a time
+        while (num-- > 0) {
+          write(' ');
+        }
+      }
+    };
+  };
+
+  /// Column - An I/O manipulator to advance the output to a certain column
+  ///
+  class Column {
+  private:
+    int column;
+
+  public:
+    explicit Column(int c) 
+        : column(c) {}
+
+    raw_asm_fd_ostream &operator()(raw_asm_fd_ostream &out) const {
+      // Make at least one space before the comment
+      out.setColumn(column, 1);
+      return(out);
+    }
+  };
+
+  inline raw_asm_fd_ostream &operator<<(raw_asm_fd_ostream &out, const Column &column)
+  {
+    return(column(out));
+  }
+
+  /// Comment - An I/O manipulator to output an end-of-line comment
+  ///
+  class Comment 
+      : public Column {
+  private:
+    static const int CommentColumn = 60;
+    std::string text;
+    const TargetAsmInfo &TAI;
+    
+  public:
+    Comment(const std::string &comment,
+            const TargetAsmInfo &tai) 
+        : Column(CommentColumn), text(comment), TAI(tai) {}
+
+    raw_asm_fd_ostream &operator()(raw_asm_fd_ostream &out) const {
+      Column::operator()(out);
+      out << TAI.getCommentString() << " " << text;
+      return(out);
+    }
+  };
+
+  inline raw_asm_fd_ostream &operator<<(raw_asm_fd_ostream &out,
+                                        const Comment &comment)
+  {
+    return(comment(out));
+  }
+
+  /// Asm stream equivalent for std streams
+  ///
+
+  /// WARNING: Do NOT use these streams in the constructors of global
+  /// objects.  There is no mechanism to ensure they are initialized
+  /// before other global objects.
+  ///
+  extern raw_asm_fd_ostream asmouts;
+  extern raw_asm_fd_ostream asmerrs;
+}
+
+#endif

lib/CodeGen/AsmStream.cpp

@@ -0,0 +1,21 @@
+//===-- llvm/CodeGen/AsmStream.cpp - AsmStream Framework --------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file was developed by the LLVM research group and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file contains instantiations of "standard" AsmOStreams.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/CodeGen/AsmStream.h"
+
+#include <unistd.h>
+
+namespace llvm {
+  raw_asm_fd_ostream asmouts(STDOUT_FILENO, false);
+  raw_asm_fd_ostream asmerrs(STDERR_FILENO, false);
+}