[llvm] r224811 - MC: Label definitions are permitted after .set directives

[David Majnemer]

Author: majnemer
Date: Wed Dec 24 04:27:50 2014
New Revision: 224811

URL: http://llvm.org/viewvc/llvm-project?rev=224811&view=rev
Log:
MC: Label definitions are permitted after .set directives

.set directives may be overridden by other .set directives as well as
label definitions.

This fixes PR22019.

Added:
    llvm/trunk/test/CodeGen/X86/pr22019.ll
Modified:
    llvm/trunk/include/llvm/MC/MCSymbol.h
    llvm/trunk/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
    llvm/trunk/lib/MC/MCParser/AsmParser.cpp
    llvm/trunk/test/MC/ELF/alias.s

Modified: llvm/trunk/include/llvm/MC/MCSymbol.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/MC/MCSymbol.h?rev=224811&r1=224810&r2=224811&view=diff
==============================================================================
--- llvm/trunk/include/llvm/MC/MCSymbol.h (original)
+++ llvm/trunk/include/llvm/MC/MCSymbol.h Wed Dec 24 04:27:50 2014
@@ -53,6 +53,9 @@ namespace llvm {
     /// "Lfoo" or ".foo".
     unsigned IsTemporary : 1;
 
+    /// \brief True if this symbol can be redefined.
+    unsigned IsRedefinable : 1;
+
     /// IsUsed - True if this symbol has been used.
     mutable unsigned IsUsed : 1;
 
@@ -61,7 +64,7 @@ namespace llvm {
     friend class MCContext;
     MCSymbol(StringRef name, bool isTemporary)
       : Name(name), Section(nullptr), Value(nullptr),
-        IsTemporary(isTemporary), IsUsed(false) {}
+        IsTemporary(isTemporary), IsRedefinable(false), IsUsed(false) {}
 
     MCSymbol(const MCSymbol&) LLVM_DELETED_FUNCTION;
     void operator=(const MCSymbol&) LLVM_DELETED_FUNCTION;
@@ -79,6 +82,19 @@ namespace llvm {
     bool isUsed() const { return IsUsed; }
     void setUsed(bool Value) const { IsUsed = Value; }
 
+    /// \brief Check if this symbol is redefinable.
+    bool isRedefinable() const { return IsRedefinable; }
+    /// \brief Mark this symbol as redefinable.
+    void setRedefinable(bool Value) { IsRedefinable = Value; }
+    /// \brief Prepare this symbol to be redefined.
+    void redefineIfPossible() {
+      if (IsRedefinable) {
+        Value = nullptr;
+        Section = nullptr;
+        IsRedefinable = false;
+      }
+    }
+
     /// @}
     /// @name Associated Sections
     /// @{

Modified: llvm/trunk/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/AsmPrinter.cpp?rev=224811&r1=224810&r2=224811&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/AsmPrinter/AsmPrinter.cpp (original)
+++ llvm/trunk/lib/CodeGen/AsmPrinter/AsmPrinter.cpp Wed Dec 24 04:27:50 2014
@@ -541,6 +541,8 @@ void AsmPrinter::EmitFunctionHeader() {
 /// EmitFunctionEntryLabel - Emit the label that is the entrypoint for the
 /// function.  This can be overridden by targets as required to do custom stuff.
 void AsmPrinter::EmitFunctionEntryLabel() {
+  CurrentFnSym->redefineIfPossible();
+
   // The function label could have already been emitted if two symbols end up
   // conflicting due to asm renaming.  Detect this and emit an error.
   if (CurrentFnSym->isUndefined())

Modified: llvm/trunk/lib/MC/MCParser/AsmParser.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/MCParser/AsmParser.cpp?rev=224811&r1=224810&r2=224811&view=diff
==============================================================================
--- llvm/trunk/lib/MC/MCParser/AsmParser.cpp (original)
+++ llvm/trunk/lib/MC/MCParser/AsmParser.cpp Wed Dec 24 04:27:50 2014
@@ -1298,6 +1298,9 @@ bool AsmParser::parseStatement(ParseStat
       Sym = getContext().GetOrCreateSymbol(IDVal);
     } else
       Sym = Ctx.CreateDirectionalLocalSymbol(LocalLabelVal);
+
+    Sym->redefineIfPossible();
+
     if (!Sym->isUndefined() || Sym->isVariable())
       return Error(IDLoc, "invalid symbol redefinition");
 
@@ -2217,6 +2220,8 @@ bool AsmParser::parseAssignment(StringRe
   } else
     Sym = getContext().GetOrCreateSymbol(Name);
 
+  Sym->setRedefinable(allow_redef);
+
   // Do the assignment.
   Out.EmitAssignment(Sym, Value);
   if (NoDeadStrip)

Added: llvm/trunk/test/CodeGen/X86/pr22019.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/pr22019.ll?rev=224811&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/X86/pr22019.ll (added)
+++ llvm/trunk/test/CodeGen/X86/pr22019.ll Wed Dec 24 04:27:50 2014
@@ -0,0 +1,12 @@
+; RUN: llc < %s | FileCheck %s
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+module asm "pselect = __pselect"
+; CHECK: pselect = __pselect
+
+; CHECK: pselect:
+; CHECK: retq
+define void @pselect() {
+  ret void
+}

Modified: llvm/trunk/test/MC/ELF/alias.s
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/MC/ELF/alias.s?rev=224811&r1=224810&r2=224811&view=diff
==============================================================================
--- llvm/trunk/test/MC/ELF/alias.s (original)
+++ llvm/trunk/test/MC/ELF/alias.s Wed Dec 24 04:27:50 2014
@@ -20,6 +20,10 @@ bar5 = bar4
 
         .long foo2
 
+// Test that bar6 is a function that doesn't have the same value as foo4.
+bar6 = bar5
+bar6:
+
 // CHECK:      Symbols [
 // CHECK-NEXT:   Symbol {
 // CHECK-NEXT:     Name:  (0)
@@ -57,6 +61,15 @@ bar5 = bar4
 // CHECK-NEXT:     Other: 0
 // CHECK-NEXT:     Section: .text
 // CHECK-NEXT:   }
+// CHECK-NEXT:   Symbol {
+// CHECK-NEXT:     Name: bar6
+// CHECK-NEXT:     Value: 0x5
+// CHECK-NEXT:     Size: 0
+// CHECK-NEXT:     Binding: Local
+// CHECK-NEXT:     Type: None
+// CHECK-NEXT:     Other: 0
+// CHECK-NEXT:     Section: .text
+// CHECK-NEXT:   }
 // CHECK-NEXT:   Symbol {
 // CHECK-NEXT:     Name: foo
 // CHECK-NEXT:     Value: 0x0