MC: Implement COFF .linkonce directive

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185753 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 26 insertions, 13 deletions

diff --git a/include/llvm/MC/MCContext.h b/include/llvm/MC/MCContext.h
index 1ebc452..c012ed0 100644
--- a/include/llvm/MC/MCContext.h
+++ b/include/llvm/MC/MCContext.h
@@ -38,6 +38,7 @@ namespace llvm {
   class Twine;
   class MCSectionMachO;
   class MCSectionELF;
+  class MCSectionCOFF;
 
   /// MCContext - Context object for machine code objects.  This class owns all
   /// of the sections that it creates.
@@ -255,14 +256,12 @@ namespace llvm {
 
     const MCSectionELF *CreateELFGroupSection();
 
-    const MCSection *getCOFFSection(StringRef Section, unsigned Characteristics,
-                                    int Selection, SectionKind Kind);
-
-    const MCSection *getCOFFSection(StringRef Section, unsigned Characteristics,
-                                    SectionKind Kind) {
-      return getCOFFSection (Section, Characteristics, 0, Kind);
-    }
+    const MCSectionCOFF *getCOFFSection(StringRef Section,
+                                        unsigned Characteristics,
+                                        SectionKind Kind, int Selection = 0,
+                                        const MCSectionCOFF *Assoc = 0);
 
+    const MCSectionCOFF *getCOFFSection(StringRef Section);
 
     /// @}
 
diff --git a/include/llvm/MC/MCSectionCOFF.h b/include/llvm/MC/MCSectionCOFF.h
index 50e33a5..754e829 100644
--- a/include/llvm/MC/MCSectionCOFF.h
+++ b/include/llvm/MC/MCSectionCOFF.h
@@ -25,22 +25,33 @@ namespace llvm {
     // The memory for this string is stored in the same MCContext as *this.
     StringRef SectionName;
 
+    // FIXME: The following fields should not be mutable, but are for now so
+    // the asm parser can honor the .linkonce directive.
+
     /// Characteristics - This is the Characteristics field of a section,
-    //  drawn from the enums below.
-    unsigned Characteristics;
+    /// drawn from the enums below.
+    mutable unsigned Characteristics;
 
     /// Selection - This is the Selection field for the section symbol, if
     /// it is a COMDAT section (Characteristics & IMAGE_SCN_LNK_COMDAT) != 0
-    int Selection;
+    mutable int Selection;
+
+    /// Assoc - This is name of the associated section, if it is a COMDAT
+    /// section (Characteristics & IMAGE_SCN_LNK_COMDAT) != 0 with an
+    /// associative Selection (IMAGE_COMDAT_SELECT_ASSOCIATIVE).
+    mutable const MCSectionCOFF *Assoc;
 
   private:
     friend class MCContext;
     MCSectionCOFF(StringRef Section, unsigned Characteristics,
-                  int Selection, SectionKind K)
+                  int Selection, const MCSectionCOFF *Assoc, SectionKind K)
       : MCSection(SV_COFF, K), SectionName(Section),
-        Characteristics(Characteristics), Selection (Selection) {
+        Characteristics(Characteristics), Selection(Selection), Assoc(Assoc) {
       assert ((Characteristics & 0x00F00000) == 0 &&
         "alignment must not be set upon section creation");
+      assert ((Selection == COFF::IMAGE_COMDAT_SELECT_ASSOCIATIVE) ==
+              (Assoc != 0) &&
+        "associative COMDAT section must have an associated section");
     }
     ~MCSectionCOFF();
 
@@ -57,7 +68,10 @@ namespace llvm {
       return SectionName.str() + "_end";
     }
     unsigned getCharacteristics() const { return Characteristics; }
-    int getSelection () const { return Selection; }
+    int getSelection() const { return Selection; }
+    const MCSectionCOFF *getAssocSection() const { return Assoc; }
+
+    void setSelection(int Selection, const MCSectionCOFF *Assoc = 0) const;
 
     virtual void PrintSwitchToSection(const MCAsmInfo &MAI,
                                       raw_ostream &OS,