[llvm-commits] [llvm] r120697 - /llvm/trunk/lib/MC/MCExpr.cpp

[Rafael Espindola]

Author: rafael
Date: Thu Dec  2 01:53:12 2010
New Revision: 120697

URL: http://llvm.org/viewvc/llvm-project?rev=120697&view=rev
Log:
Add a fast path to EvaluateSymbolicAdd. This avoids computing symbol addresses
which then avoids running EnsureValid.
This cuts the assembly time of the testcase in PR8711 from 2:50 minutes to 1
minute.

Modified:
    llvm/trunk/lib/MC/MCExpr.cpp

Modified: llvm/trunk/lib/MC/MCExpr.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/MCExpr.cpp?rev=120697&r1=120696&r2=120697&view=diff
==============================================================================
--- llvm/trunk/lib/MC/MCExpr.cpp (original)
+++ llvm/trunk/lib/MC/MCExpr.cpp Thu Dec  2 01:53:12 2010
@@ -294,12 +294,20 @@
   if (Layout && A && B) {
     const MCSymbol &SA = A->getSymbol();
     const MCSymbol &SB = B->getSymbol();
-    const MCObjectFormat &F =
-      Layout->getAssembler().getBackend().getObjectFormat();
+    const MCAssembler &Asm = Layout->getAssembler();
+    const MCObjectFormat &F = Asm.getBackend().getObjectFormat();
     if (SA.isDefined() && SB.isDefined() && F.isAbsolute(InSet, SA, SB)) {
-      const MCAssembler &Asm = Layout->getAssembler();
       MCSymbolData &AD = Asm.getSymbolData(A->getSymbol());
       MCSymbolData &BD = Asm.getSymbolData(B->getSymbol());
+
+      if (AD.getFragment() == BD.getFragment()) {
+        Res = MCValue::get(+ AD.getOffset()
+                           - BD.getOffset()
+                           + LHS.getConstant()
+                           + RHS_Cst);
+        return true;
+      }
+
       Res = MCValue::get(+ Layout->getSymbolAddress(&AD)
                          - Layout->getSymbolAddress(&BD)
                          + LHS.getConstant()