[llvm-commits] [llvm] r103690 - in /llvm/trunk: include/llvm/MC/MCAssembler.h lib/MC/MCAssembler.cpp

[Daniel Dunbar]

Author: ddunbar
Date: Wed May 12 20:10:26 2010
New Revision: 103690

URL: http://llvm.org/viewvc/llvm-project?rev=103690&view=rev
Log:
MC: Add MCAlignFragment::OnlyAlignAddress bit. This is a bit of magic that says the align fragment shouldn't contribute to the logical section size, it is will be used for cleaning up the code to handle section alignment.

Modified:
    llvm/trunk/include/llvm/MC/MCAssembler.h
    llvm/trunk/lib/MC/MCAssembler.cpp

Modified: llvm/trunk/include/llvm/MC/MCAssembler.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/MC/MCAssembler.h?rev=103690&r1=103689&r2=103690&view=diff
==============================================================================
--- llvm/trunk/include/llvm/MC/MCAssembler.h (original)
+++ llvm/trunk/include/llvm/MC/MCAssembler.h Wed May 12 20:10:26 2010
@@ -258,12 +258,19 @@
   /// target dependent.
   bool EmitNops : 1;
 
+  /// OnlyAlignAddress - Flag to indicate that this align is only used to adjust
+  /// the address space size of a section and that it should not be included as
+  /// part of the section size. This flag can only be used on the last fragment
+  /// in a section.
+  bool OnlyAlignAddress : 1;
+
 public:
   MCAlignFragment(unsigned _Alignment, int64_t _Value, unsigned _ValueSize,
                   unsigned _MaxBytesToEmit, MCSectionData *SD = 0)
     : MCFragment(FT_Align, SD), Alignment(_Alignment),
       Value(_Value),ValueSize(_ValueSize),
-      MaxBytesToEmit(_MaxBytesToEmit), EmitNops(false) {}
+      MaxBytesToEmit(_MaxBytesToEmit), EmitNops(false),
+      OnlyAlignAddress(false) {}
 
   /// @name Accessors
   /// @{
@@ -279,6 +286,9 @@
   bool hasEmitNops() const { return EmitNops; }
   void setEmitNops(bool Value) { EmitNops = Value; }
 
+  bool hasOnlyAlignAddress() const { return OnlyAlignAddress; }
+  void setOnlyAlignAddress(bool Value) { OnlyAlignAddress = Value; }
+
   /// @}
 
   static bool classof(const MCFragment *F) {

Modified: llvm/trunk/lib/MC/MCAssembler.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/MCAssembler.cpp?rev=103690&r1=103689&r2=103690&view=diff
==============================================================================
--- llvm/trunk/lib/MC/MCAssembler.cpp (original)
+++ llvm/trunk/lib/MC/MCAssembler.cpp Wed May 12 20:10:26 2010
@@ -392,6 +392,9 @@
   case MCFragment::FT_Align: {
     MCAlignFragment &AF = cast<MCAlignFragment>(F);
 
+    assert((!AF.hasOnlyAlignAddress() || !AF.getNextNode()) &&
+           "Invalid OnlyAlignAddress bit, not the last fragment!");
+
     EffectiveSize = OffsetToAlignment(Address, AF.getAlignment());
     if (EffectiveSize > AF.getMaxBytesToEmit())
       EffectiveSize = 0;
@@ -474,9 +477,18 @@
     MCFragment *F = &SD.getFragmentList().back();
     Size = Layout.getFragmentOffset(F) + Layout.getFragmentEffectiveSize(F);
   }
-  Layout.setSectionSize(&SD, Size);
   Layout.setSectionAddressSize(&SD, Size);
   Layout.setSectionFileSize(&SD, IsVirtual ? 0 : Size);
+
+  // Handle OnlyAlignAddress bit.
+  if (!SD.getFragmentList().empty()) {
+    MCAlignFragment *AF =
+      dyn_cast<MCAlignFragment>(&SD.getFragmentList().back());
+    if (AF && AF->hasOnlyAlignAddress())
+      Size -= Layout.getFragmentEffectiveSize(AF);
+  }
+
+  Layout.setSectionSize(&SD, Size);
 }
 
 /// WriteFragmentData - Write the \arg F data to the output file.
@@ -856,6 +868,10 @@
 
   OS << "<MCAlignFragment ";
   this->MCFragment::dump();
+  if (hasEmitNops())
+    OS << " (emit nops)";
+  if (hasOnlyAlignAddress())
+    OS << " (only align section)";
   OS << "\n       ";
   OS << " Alignment:" << getAlignment()
      << " Value:" << getValue() << " ValueSize:" << getValueSize()