X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FMC%2FMCAssembler.cpp;h=a6aa5da2421a5be2969b62641098e48046b22b85;hb=70d641fbecf2ce54fd3578890c94888fad254238;hp=a96e4ba15146f4d851b46aca83845312b2edb9a8;hpb=ff56f416a5f0fecc7c996efd1e903fd36afe8bee;p=oota-llvm.git

diff --git a/lib/MC/MCAssembler.cpp b/lib/MC/MCAssembler.cpp
index a96e4ba1514..a6aa5da2421 100644
--- a/lib/MC/MCAssembler.cpp
+++ b/lib/MC/MCAssembler.cpp
@@ -27,6 +27,7 @@
 #include "llvm/Support/LEB128.h"
 #include "llvm/Support/TargetRegistry.h"
 #include "llvm/Support/raw_ostream.h"
+#include "llvm/MC/MCSectionELF.h"
 #include <tuple>
 using namespace llvm;
 
@@ -118,37 +119,88 @@ uint64_t MCAsmLayout::getFragmentOffset(const MCFragment *F) const {
 }
 
 // Simple getSymbolOffset helper for the non-varibale case.
-static uint64_t getLabelOffset(const MCAsmLayout &Layout,
-                               const MCSymbolData &SD) {
-  if (!SD.getFragment())
-    report_fatal_error("unable to evaluate offset to undefined symbol '" +
-                       SD.getSymbol().getName() + "'");
-  return Layout.getFragmentOffset(SD.getFragment()) + SD.getOffset();
+static bool getLabelOffset(const MCAsmLayout &Layout, const MCSymbolData &SD,
+                           bool ReportError, uint64_t &Val) {
+  if (!SD.getFragment()) {
+    if (ReportError)
+      report_fatal_error("unable to evaluate offset to undefined symbol '" +
+                         SD.getSymbol().getName() + "'");
+    return false;
+  }
+  Val = Layout.getFragmentOffset(SD.getFragment()) + SD.getOffset();
+  return true;
 }
 
-uint64_t MCAsmLayout::getSymbolOffset(const MCSymbolData *SD) const {
+static bool getSymbolOffsetImpl(const MCAsmLayout &Layout,
+                                const MCSymbolData *SD, bool ReportError,
+                                uint64_t &Val) {
   const MCSymbol &S = SD->getSymbol();
 
   if (!S.isVariable())
-    return getLabelOffset(*this, *SD);
+    return getLabelOffset(Layout, *SD, ReportError, Val);
 
   // If SD is a variable, evaluate it.
   MCValue Target;
-  if (!S.getVariableValue()->EvaluateAsValue(Target, this))
+  if (!S.getVariableValue()->EvaluateAsValue(Target, &Layout, nullptr))
     report_fatal_error("unable to evaluate offset for variable '" +
                        S.getName() + "'");
 
   uint64_t Offset = Target.getConstant();
 
+  const MCAssembler &Asm = Layout.getAssembler();
+
   const MCSymbolRefExpr *A = Target.getSymA();
-  if (A)
-    Offset += getLabelOffset(*this, Assembler.getSymbolData(A->getSymbol()));
+  if (A) {
+    uint64_t ValA;
+    if (!getLabelOffset(Layout, Asm.getSymbolData(A->getSymbol()), ReportError,
+                        ValA))
+      return false;
+    Offset += ValA;
+  }
 
   const MCSymbolRefExpr *B = Target.getSymB();
-  if (B)
-    Offset -= getLabelOffset(*this, Assembler.getSymbolData(B->getSymbol()));
+  if (B) {
+    uint64_t ValB;
+    if (!getLabelOffset(Layout, Asm.getSymbolData(B->getSymbol()), ReportError,
+                        ValB))
+      return false;
+    Offset -= ValB;
+  }
+
+  Val = Offset;
+  return true;
+}
 
-  return Offset;
+bool MCAsmLayout::getSymbolOffset(const MCSymbolData *SD, uint64_t &Val) const {
+  return getSymbolOffsetImpl(*this, SD, false, Val);
+}
+
+uint64_t MCAsmLayout::getSymbolOffset(const MCSymbolData *SD) const {
+  uint64_t Val;
+  getSymbolOffsetImpl(*this, SD, true, Val);
+  return Val;
+}
+
+const MCSymbol *MCAsmLayout::getBaseSymbol(const MCSymbol &Symbol) const {
+  if (!Symbol.isVariable())
+    return &Symbol;
+
+  const MCExpr *Expr = Symbol.getVariableValue();
+  MCValue Value;
+  if (!Expr->EvaluateAsValue(Value, this, nullptr))
+    llvm_unreachable("Invalid Expression");
+
+  const MCSymbolRefExpr *RefB = Value.getSymB();
+  if (RefB)
+    Assembler.getContext().FatalError(
+        SMLoc(), Twine("symbol '") + RefB->getSymbol().getName() +
+                     "' could not be evaluated in a subtraction expression");
+
+  const MCSymbolRefExpr *A = Value.getSymA();
+  if (!A)
+    return nullptr;
+
+  return &A->getSymbol();
 }
 
 uint64_t MCAsmLayout::getSectionAddressSize(const MCSectionData *SD) const {
@@ -382,12 +434,28 @@ const MCSymbolData *MCAssembler::getAtom(const MCSymbolData *SD) const {
   return SD->getFragment()->getAtom();
 }
 
+// Try to fully compute Expr to an absolute value and if that fails produce
+// a relocatable expr.
+// FIXME: Should this be the behavior of EvaluateAsRelocatable itself?
+static bool evaluate(const MCExpr &Expr, const MCAsmLayout &Layout,
+                     const MCFixup &Fixup, MCValue &Target) {
+  if (Expr.EvaluateAsValue(Target, &Layout, &Fixup)) {
+    if (Target.isAbsolute())
+      return true;
+  }
+  return Expr.EvaluateAsRelocatable(Target, &Layout, &Fixup);
+}
+
 bool MCAssembler::evaluateFixup(const MCAsmLayout &Layout,
                                 const MCFixup &Fixup, const MCFragment *DF,
                                 MCValue &Target, uint64_t &Value) const {
   ++stats::evaluateFixup;
 
-  if (!Fixup.getValue()->EvaluateAsRelocatable(Target, &Layout))
+  // FIXME: This code has some duplication with RecordRelocation. We should
+  // probably merge the two into a single callback that tries to evaluate a
+  // fixup and records a relocation if one is needed.
+  const MCExpr *Expr = Fixup.getValue();
+  if (!evaluate(*Expr, Layout, Fixup, Target))
     getContext().FatalError(Fixup.getLoc(), "expected relocatable expression");
 
   bool IsPCRel = Backend.getFixupKindInfo(
@@ -731,8 +799,13 @@ void MCAssembler::writeSectionData(const MCSectionData *SD,
         assert(DF.fixup_begin() == DF.fixup_end() &&
                "Cannot have fixups in virtual section!");
         for (unsigned i = 0, e = DF.getContents().size(); i != e; ++i)
-          assert(DF.getContents()[i] == 0 &&
-                 "Invalid data value for virtual section!");
+          if (DF.getContents()[i]) {
+            if (auto *ELFSec = dyn_cast<const MCSectionELF>(&SD->getSection()))
+              report_fatal_error("non-zero initializer found in section '" +
+                  ELFSec->getSectionName() + "'");
+            else
+              report_fatal_error("non-zero initializer found in virtual section");
+          }
         break;
       }
       case MCFragment::FT_Align:
@@ -921,11 +994,8 @@ bool MCAssembler::relaxInstruction(MCAsmLayout &Layout,
 }
 
 bool MCAssembler::relaxLEB(MCAsmLayout &Layout, MCLEBFragment &LF) {
-  int64_t Value = 0;
   uint64_t OldSize = LF.getContents().size();
-  bool IsAbs = LF.getValue().EvaluateAsAbsolute(Value, Layout);
-  (void)IsAbs;
-  assert(IsAbs);
+  int64_t Value = LF.getValue().evaluateKnownAbsolute(Layout);
   SmallString<8> &Data = LF.getContents();
   Data.clear();
   raw_svector_ostream OSE(Data);
@@ -940,11 +1010,8 @@ bool MCAssembler::relaxLEB(MCAsmLayout &Layout, MCLEBFragment &LF) {
 bool MCAssembler::relaxDwarfLineAddr(MCAsmLayout &Layout,
                                      MCDwarfLineAddrFragment &DF) {
   MCContext &Context = Layout.getAssembler().getContext();
-  int64_t AddrDelta = 0;
   uint64_t OldSize = DF.getContents().size();
-  bool IsAbs = DF.getAddrDelta().EvaluateAsAbsolute(AddrDelta, Layout);
-  (void)IsAbs;
-  assert(IsAbs);
+  int64_t AddrDelta = DF.getAddrDelta().evaluateKnownAbsolute(Layout);
   int64_t LineDelta;
   LineDelta = DF.getLineDelta();
   SmallString<8> &Data = DF.getContents();
@@ -958,11 +1025,8 @@ bool MCAssembler::relaxDwarfLineAddr(MCAsmLayout &Layout,
 bool MCAssembler::relaxDwarfCallFrameFragment(MCAsmLayout &Layout,
                                               MCDwarfCallFrameFragment &DF) {
   MCContext &Context = Layout.getAssembler().getContext();
-  int64_t AddrDelta = 0;
   uint64_t OldSize = DF.getContents().size();
-  bool IsAbs = DF.getAddrDelta().EvaluateAsAbsolute(AddrDelta, Layout);
-  (void)IsAbs;
-  assert(IsAbs);
+  int64_t AddrDelta = DF.getAddrDelta().evaluateKnownAbsolute(Layout);
   SmallString<8> &Data = DF.getContents();
   Data.clear();
   raw_svector_ostream OSE(Data);
@@ -1171,7 +1235,7 @@ void MCSectionData::dump() {
   OS << "]>";
 }
 
-void MCSymbolData::dump() {
+void MCSymbolData::dump() const {
   raw_ostream &OS = llvm::errs();
 
   OS << "<MCSymbolData Symbol:" << getSymbol()