[llvm-commits] [llvm] r122165 - /llvm/trunk/lib/MC/MCExpr.cpp

[Rafael Espindola]

Author: rafael
Date: Sat Dec 18 21:22:05 2010
New Revision: 122165

URL: http://llvm.org/viewvc/llvm-project?rev=122165&view=rev
Log:
Revert 122160 while I debug it.

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=122165&r1=122164&r2=122165&view=diff
==============================================================================
--- llvm/trunk/lib/MC/MCExpr.cpp (original)
+++ llvm/trunk/lib/MC/MCExpr.cpp Sat Dec 18 21:22:05 2010
@@ -293,47 +293,22 @@
 }
 
 /// \brief Helper method for \see EvaluateSymbolAdd().
-static void AttemptToFoldSymbolOffsetDifference(const MCAssembler *Asm,
-                                                const MCAsmLayout *Layout,
-                                                const SectionAddrMap *Addrs,
-                                                bool InSet,
+static void AttemptToFoldSymbolOffsetDifference(const MCAsmLayout *Layout,
                                                 const MCSymbolRefExpr *&A,
                                                 const MCSymbolRefExpr *&B,
                                                 int64_t &Addend) {
-  if (!A || !B ||
-      !Asm->getWriter().IsSymbolRefDifferenceFullyResolved(*Asm, A, B, InSet))
-    return;
+  const MCAssembler &Asm = Layout->getAssembler();
 
-  MCSymbolData &AD = Asm->getSymbolData(A->getSymbol());
-  MCSymbolData &BD = Asm->getSymbolData(B->getSymbol());
-
-  if (AD.getFragment() == BD.getFragment()) {
-    Addend += (AD.getOffset() - BD.getOffset());
+  if (A && B &&
+      Asm.getWriter().IsSymbolRefDifferenceFullyResolved(Asm, A, B, false)) {
+    // Eagerly evaluate.
+    Addend += (Layout->getSymbolOffset(&Asm.getSymbolData(A->getSymbol())) -
+               Layout->getSymbolOffset(&Asm.getSymbolData(B->getSymbol())));
 
     // Clear the symbol expr pointers to indicate we have folded these
     // operands.
     A = B = 0;
-    return;
   }
-
-  if (!Layout)
-    return;
-
-  const MCSectionData &SecA = *AD.getFragment()->getParent();
-  const MCSectionData &SecB = *BD.getFragment()->getParent();
-
-  if ((&SecA != &SecB) && !Addrs)
-    return;
-
-  // Eagerly evaluate.
-  Addend += (Layout->getSymbolOffset(&Asm->getSymbolData(A->getSymbol())) -
-             Layout->getSymbolOffset(&Asm->getSymbolData(B->getSymbol())));
-  if (Addrs && (&SecA != &SecB))
-    Addend += (Addrs->lookup(&SecA) - Addrs->lookup(&SecB));
-
-  // Clear the symbol expr pointers to indicate we have folded these
-  // operands.
-  A = B = 0;
 }
 
 /// \brief Evaluate the result of an add between (conceptually) two MCValues.
@@ -371,11 +346,8 @@
   // Fold the result constant immediately.
   int64_t Result_Cst = LHS_Cst + RHS_Cst;
 
-  assert((!Layout || Asm) &&
-         "Must have an assembler object if layout is given!");
-
   // If we have a layout, we can fold resolved differences.
-  if (Asm) {
+  if (Layout) {
     // First, fold out any differences which are fully resolved. By
     // reassociating terms in
     //   Result = (LHS_A - LHS_B + LHS_Cst) + (RHS_A - RHS_B + RHS_Cst).
@@ -386,14 +358,10 @@
     //   (RHS_A - RHS_B).
     // Since we are attempting to be as aggresive as possible about folding, we
     // attempt to evaluate each possible alternative.
-    AttemptToFoldSymbolOffsetDifference(Asm, Layout, Addrs, InSet, LHS_A, LHS_B,
-                                        Result_Cst);
-    AttemptToFoldSymbolOffsetDifference(Asm, Layout, Addrs, InSet, LHS_A, RHS_B,
-                                        Result_Cst);
-    AttemptToFoldSymbolOffsetDifference(Asm, Layout, Addrs, InSet, RHS_A, LHS_B,
-                                        Result_Cst);
-    AttemptToFoldSymbolOffsetDifference(Asm, Layout, Addrs, InSet, RHS_A, RHS_B,
-                                        Result_Cst);
+    AttemptToFoldSymbolOffsetDifference(Layout, LHS_A, LHS_B, Result_Cst);
+    AttemptToFoldSymbolOffsetDifference(Layout, LHS_A, RHS_B, Result_Cst);
+    AttemptToFoldSymbolOffsetDifference(Layout, RHS_A, LHS_B, Result_Cst);
+    AttemptToFoldSymbolOffsetDifference(Layout, RHS_A, RHS_B, Result_Cst);
   }
 
   // We can't represent the addition or subtraction of two symbols.
@@ -410,6 +378,44 @@
   if (B && !A)
     return false;
 
+  // Absolutize symbol differences between defined symbols when we have a
+  // layout object and the target requests it.
+
+  assert((!Layout || Asm) &&
+         "Must have an assembler object if layout is given!");
+
+  if (Asm && A && B) {
+    if (A->getSymbol().isDefined() && B->getSymbol().isDefined() &&
+        Asm->getWriter().IsSymbolRefDifferenceFullyResolved(*Asm, A, B,
+                                                            InSet)) {
+      MCSymbolData &AD = Asm->getSymbolData(A->getSymbol());
+      MCSymbolData &BD = Asm->getSymbolData(B->getSymbol());
+
+      if (AD.getFragment() == BD.getFragment()) {
+        Res = MCValue::get(+ AD.getOffset()
+                           - BD.getOffset()
+                           + Result_Cst);
+        return true;
+      }
+
+      if (Layout) {
+        const MCSectionData &SecA = *AD.getFragment()->getParent();
+        const MCSectionData &SecB = *BD.getFragment()->getParent();
+        int64_t Val = + Layout->getSymbolOffset(&AD)
+                      - Layout->getSymbolOffset(&BD)
+                      + Result_Cst;
+        if (&SecA != &SecB) {
+          if (!Addrs)
+            return false;
+          Val += Addrs->lookup(&SecA);
+          Val -= Addrs->lookup(&SecB);
+        }
+        Res = MCValue::get(Val);
+        return true;
+      }
+    }
+  }
+
   Res = MCValue::get(A, B, Result_Cst);
   return true;
 }