Convert a few assert failures into proper errors.

Fixes PR25944.

llvm-svn: 257697
diff --git a/llvm/lib/Target/X86/MCTargetDesc/X86ELFObjectWriter.cpp b/llvm/lib/Target/X86/MCTargetDesc/X86ELFObjectWriter.cpp
index 736c39d..f2e519a 100644
--- a/llvm/lib/Target/X86/MCTargetDesc/X86ELFObjectWriter.cpp
+++ b/llvm/lib/Target/X86/MCTargetDesc/X86ELFObjectWriter.cpp
@@ -9,6 +9,7 @@
 
 #include "MCTargetDesc/X86FixupKinds.h"
 #include "MCTargetDesc/X86MCTargetDesc.h"
+#include "llvm/MC/MCContext.h"
 #include "llvm/MC/MCELFObjectWriter.h"
 #include "llvm/MC/MCExpr.h"
 #include "llvm/MC/MCValue.h"
@@ -25,8 +26,8 @@
     ~X86ELFObjectWriter() override;
 
   protected:
-    unsigned GetRelocType(const MCValue &Target, const MCFixup &Fixup,
-                          bool IsPCRel) const override;
+    unsigned getRelocType(MCContext &Ctx, const MCValue &Target,
+                          const MCFixup &Fixup, bool IsPCRel) const override;
   };
 }
 
@@ -77,7 +78,14 @@
   }
 }
 
-static unsigned getRelocType64(MCSymbolRefExpr::VariantKind Modifier,
+static void checkIs32(MCContext &Ctx, SMLoc Loc, X86_64RelType Type) {
+  if (Type != RT64_32)
+    Ctx.reportError(Loc,
+                    "32 bit reloc applied to a field with a different size");
+}
+
+static unsigned getRelocType64(MCContext &Ctx, SMLoc Loc,
+                               MCSymbolRefExpr::VariantKind Modifier,
                                X86_64RelType Type, bool IsPCRel) {
   switch (Modifier) {
   default:
@@ -147,19 +155,19 @@
       llvm_unreachable("Unimplemented");
     }
   case MCSymbolRefExpr::VK_TLSGD:
-    assert(Type == RT64_32);
+    checkIs32(Ctx, Loc, Type);
     return ELF::R_X86_64_TLSGD;
   case MCSymbolRefExpr::VK_GOTTPOFF:
-    assert(Type == RT64_32);
+    checkIs32(Ctx, Loc, Type);
     return ELF::R_X86_64_GOTTPOFF;
   case MCSymbolRefExpr::VK_TLSLD:
-    assert(Type == RT64_32);
+    checkIs32(Ctx, Loc, Type);
     return ELF::R_X86_64_TLSLD;
   case MCSymbolRefExpr::VK_PLT:
-    assert(Type == RT64_32);
+    checkIs32(Ctx, Loc, Type);
     return ELF::R_X86_64_PLT32;
   case MCSymbolRefExpr::VK_GOTPCREL:
-    assert(Type == RT64_32);
+    checkIs32(Ctx, Loc, Type);
     return ELF::R_X86_64_GOTPCREL;
   }
 }
@@ -240,13 +248,13 @@
   }
 }
 
-unsigned X86ELFObjectWriter::GetRelocType(const MCValue &Target,
+unsigned X86ELFObjectWriter::getRelocType(MCContext &Ctx, const MCValue &Target,
                                           const MCFixup &Fixup,
                                           bool IsPCRel) const {
   MCSymbolRefExpr::VariantKind Modifier = Target.getAccessVariant();
   X86_64RelType Type = getType64(Fixup.getKind(), Modifier, IsPCRel);
   if (getEMachine() == ELF::EM_X86_64)
-    return getRelocType64(Modifier, Type, IsPCRel);
+    return getRelocType64(Ctx, Fixup.getLoc(), Modifier, Type, IsPCRel);
 
   assert((getEMachine() == ELF::EM_386 || getEMachine() == ELF::EM_IAMCU) &&
          "Unsupported ELF machine type.");