Fix the assembler to print a better relocatable expression error

diagnostic that includes location information.

Currently if one has this assembly:

	.quad (0x1234 + (4 * SOME_VALUE))

where SOME_VALUE is undefined ones gets the less than
useful error message with no location information:

% clang -c x.s
clang -cc1as: fatal error: error in backend: expected relocatable expression

With this fix one now gets a more useful error message
with location information:

% clang -c x.s 
x.s:5:8: error: expected relocatable expression
 .quad (0x1234 + (4 * SOME_VALUE))
       ^

To do this I plumbed the SMLoc through the MCObjectStreamer
EmitValue() and EmitValueImpl() interfaces so it could be used
when creating the MCFixup.

rdar://12391022


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206906 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/MC/MCELFStreamer.h

@@ -72,7 +72,8 @@ public:
                     uint64_t Size = 0, unsigned ByteAlignment = 0) override;
   void EmitTBSSSymbol(const MCSection *Section, MCSymbol *Symbol,
                       uint64_t Size, unsigned ByteAlignment = 0) override;
-  void EmitValueImpl(const MCExpr *Value, unsigned Size) override;
+  void EmitValueImpl(const MCExpr *Value, unsigned Size,
+                     const SMLoc &Loc = SMLoc()) override;
 
   void EmitFileDirective(StringRef Filename) override;
 

include/llvm/MC/MCObjectStreamer.h

@@ -81,7 +81,8 @@ public:
   void EmitLabel(MCSymbol *Symbol) override;
   void EmitDebugLabel(MCSymbol *Symbol) override;
   void EmitAssignment(MCSymbol *Symbol, const MCExpr *Value) override;
-  void EmitValueImpl(const MCExpr *Value, unsigned Size) override;
+  void EmitValueImpl(const MCExpr *Value, unsigned Size,
+                     const SMLoc &Loc = SMLoc()) override;
   void EmitULEB128Value(const MCExpr *Value) override;
   void EmitSLEB128Value(const MCExpr *Value) override;
   void EmitWeakReference(MCSymbol *Alias, const MCSymbol *Symbol) override;

include/llvm/MC/MCStreamer.h

@@ -529,9 +529,12 @@ public:
   /// @param Value - The value to emit.
   /// @param Size - The size of the integer (in bytes) to emit. This must
   /// match a native machine width.
-  virtual void EmitValueImpl(const MCExpr *Value, unsigned Size) = 0;
+  /// @param Loc - The location of the expression for error reporting.
+  virtual void EmitValueImpl(const MCExpr *Value, unsigned Size,
+                             const SMLoc &Loc = SMLoc()) = 0;
 
-  void EmitValue(const MCExpr *Value, unsigned Size);
+  void EmitValue(const MCExpr *Value, unsigned Size,
+                 const SMLoc &Loc = SMLoc());
 
   /// EmitIntValue - Special case of EmitValue that avoids the client having
   /// to pass in a MCExpr for constant integers.

lib/LTO/LTOModule.cpp

@@ -698,7 +698,8 @@ namespace {
     void EmitTBSSSymbol(const MCSection *Section, MCSymbol *Symbol,
                         uint64_t Size, unsigned ByteAlignment) override {}
     void EmitBytes(StringRef Data) override {}
-    void EmitValueImpl(const MCExpr *Value, unsigned Size) override {}
+    void EmitValueImpl(const MCExpr *Value, unsigned Size,
+                       const SMLoc &Loc) override {}
     void EmitULEB128Value(const MCExpr *Value) override {}
     void EmitSLEB128Value(const MCExpr *Value) override {}
     void EmitValueToAlignment(unsigned ByteAlignment, int64_t Value,

lib/MC/MCAsmStreamer.cpp

@@ -175,7 +175,8 @@ public:
 
   void EmitBytes(StringRef Data) override;
 
-  void EmitValueImpl(const MCExpr *Value, unsigned Size) override;
+  void EmitValueImpl(const MCExpr *Value, unsigned Size,
+                     const SMLoc &Loc = SMLoc()) override;
   void EmitIntValue(uint64_t Value, unsigned Size) override;
 
   void EmitULEB128Value(const MCExpr *Value) override;
@@ -702,7 +703,8 @@ void MCAsmStreamer::EmitIntValue(uint64_t Value, unsigned Size) {
   EmitValue(MCConstantExpr::Create(Value, getContext()), Size);
 }
 
-void MCAsmStreamer::EmitValueImpl(const MCExpr *Value, unsigned Size) {
+void MCAsmStreamer::EmitValueImpl(const MCExpr *Value, unsigned Size,
+                                  const SMLoc &Loc) {
   assert(Size <= 8 && "Invalid size");
   assert(getCurrentSection().first &&
          "Cannot emit contents before setting section!");

lib/MC/MCELFStreamer.cpp

@@ -275,11 +275,12 @@ void MCELFStreamer::EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size,
   EmitCommonSymbol(Symbol, Size, ByteAlignment);
 }
 
-void MCELFStreamer::EmitValueImpl(const MCExpr *Value, unsigned Size) {
+void MCELFStreamer::EmitValueImpl(const MCExpr *Value, unsigned Size,
+                                  const SMLoc &Loc) {
   if (getCurrentSectionData()->isBundleLocked())
     report_fatal_error("Emitting values inside a locked bundle is forbidden");
   fixSymbolsInTLSFixups(Value);
-  MCObjectStreamer::EmitValueImpl(Value, Size);
+  MCObjectStreamer::EmitValueImpl(Value, Size, Loc);
 }
 
 void MCELFStreamer::EmitValueToAlignment(unsigned ByteAlignment,

lib/MC/MCNullStreamer.cpp

@@ -70,7 +70,8 @@ namespace {
                         uint64_t Size, unsigned ByteAlignment) override {}
     void EmitBytes(StringRef Data) override {}
 
-    void EmitValueImpl(const MCExpr *Value, unsigned Size) override {}
+    void EmitValueImpl(const MCExpr *Value, unsigned Size,
+                       const SMLoc &Loc = SMLoc()) override {}
     void EmitULEB128Value(const MCExpr *Value) override {}
     void EmitSLEB128Value(const MCExpr *Value) override {}
     void EmitGPRel32Value(const MCExpr *Value) override {}

lib/MC/MCObjectStreamer.cpp

@@ -97,7 +97,8 @@ const MCExpr *MCObjectStreamer::AddValueSymbols(const MCExpr *Value) {
   return Value;
 }
 
-void MCObjectStreamer::EmitValueImpl(const MCExpr *Value, unsigned Size) {
+void MCObjectStreamer::EmitValueImpl(const MCExpr *Value, unsigned Size,
+                                     const SMLoc &Loc) {
   MCDataFragment *DF = getOrCreateDataFragment();
 
   MCLineEntry::Make(this, getCurrentSection().first);
@@ -110,7 +111,7 @@ void MCObjectStreamer::EmitValueImpl(const MCExpr *Value, unsigned Size) {
   }
   DF->getFixups().push_back(
       MCFixup::Create(DF->getContents().size(), Value,
-                      MCFixup::getKindForSize(Size, false)));
+                      MCFixup::getKindForSize(Size, false), Loc));
   DF->getContents().resize(DF->getContents().size() + Size, 0);
 }
 

lib/MC/MCParser/AsmParser.cpp

@@ -2364,7 +2364,7 @@ bool AsmParser::parseDirectiveValue(unsigned Size) {
           return Error(ExprLoc, "literal value out of range for directive");
         getStreamer().EmitIntValue(IntValue, Size);
       } else
-        getStreamer().EmitValue(Value, Size);
+        getStreamer().EmitValue(Value, Size, ExprLoc);
 
       if (getLexer().is(AsmToken::EndOfStatement))
         break;

lib/MC/MCStreamer.cpp

@@ -147,8 +147,9 @@ void MCStreamer::EmitAbsValue(const MCExpr *Value, unsigned Size) {
 }
 
 
-void MCStreamer::EmitValue(const MCExpr *Value, unsigned Size) {
+void MCStreamer::EmitValue(const MCExpr *Value, unsigned Size,
-  EmitValueImpl(Value, Size);
+                           const SMLoc &Loc) {
+  EmitValueImpl(Value, Size, Loc);
 }
 
 void MCStreamer::EmitSymbolValue(const MCSymbol *Sym, unsigned Size) {

lib/Target/AArch64/MCTargetDesc/AArch64ELFStreamer.cpp

@@ -92,9 +92,10 @@ public:
   /// This is one of the functions used to emit data into an ELF section, so the
   /// AArch64 streamer overrides it to add the appropriate mapping symbol ($d)
   /// if necessary.
-  virtual void EmitValueImpl(const MCExpr *Value, unsigned Size) {
+  virtual void EmitValueImpl(const MCExpr *Value, unsigned Size,
+                             const SMLoc &Loc) {
     EmitDataMappingSymbol();
-    MCELFStreamer::EmitValueImpl(Value, Size);
+    MCELFStreamer::EmitValueImpl(Value, Size, Loc);
   }
 
 private:

lib/Target/ARM/MCTargetDesc/ARMELFStreamer.cpp

@@ -531,7 +531,8 @@ public:
   /// This is one of the functions used to emit data into an ELF section, so the
   /// ARM streamer overrides it to add the appropriate mapping symbol ($d) if
   /// necessary.
-  void EmitValueImpl(const MCExpr *Value, unsigned Size) override {
+  void EmitValueImpl(const MCExpr *Value, unsigned Size,
+                     const SMLoc &Loc) override {
     EmitDataMappingSymbol();
     MCELFStreamer::EmitValueImpl(Value, Size);
   }

lib/Target/ARM64/MCTargetDesc/ARM64ELFStreamer.cpp

@@ -92,7 +92,8 @@ public:
   /// This is one of the functions used to emit data into an ELF section, so the
   /// ARM64 streamer overrides it to add the appropriate mapping symbol ($d)
   /// if necessary.
-  virtual void EmitValueImpl(const MCExpr *Value, unsigned Size) {
+  virtual void EmitValueImpl(const MCExpr *Value, unsigned Size,
+                             const SMLoc &Loc) {
     EmitDataMappingSymbol();
     MCELFStreamer::EmitValueImpl(Value, Size);
   }

test/MC/MachO/bad-darwin-x86_64-reloc-expr.s

@@ -0,0 +1,6 @@
+// RUN: not llvm-mc -triple x86_64-apple-darwin10 %s -filetype=obj -o - 2> %t.err > %t
+// RUN: FileCheck --check-prefix=CHECK-ERROR < %t.err %s
+
+.quad (0x1234 + (4 * SOME_VALUE))
+// CHECK-ERROR: error: expected relocatable expression
+// CHECK-ERROR:               ^