ARM: fail less catastrophically on invalid Windows input

Windows supports a restricted set of relocations (compared to ARM ELF).  In some
cases, we may end up generating an unsupported relocation.  This can occur with
bad input to the assembler in particular (the frontend should never generate
code that cannot be compiled).  Generate an error rather than just aborting.

The change in the API is driven by the desire to provide a slightly more helpful
message for debugging purposes.

llvm-svn: 226779

5 files changed, 40 insertions, 14 deletions

diff --git a/llvm/include/llvm/MC/MCWinCOFFObjectWriter.h b/llvm/include/llvm/MC/MCWinCOFFObjectWriter.h
index dad7bb59703..956e43642c3 100644
--- a/llvm/include/llvm/MC/MCWinCOFFObjectWriter.h
+++ b/llvm/include/llvm/MC/MCWinCOFFObjectWriter.h
@@ -11,10 +11,11 @@
 #define LLVM_MC_MCWINCOFFOBJECTWRITER_H
 
 namespace llvm {
-  class MCFixup;
-  class MCObjectWriter;
-  class MCValue;
-  class raw_ostream;
+class MCAsmBackend;
+class MCFixup;
+class MCObjectWriter;
+class MCValue;
+class raw_ostream;
 
   class MCWinCOFFObjectTargetWriter {
     virtual void anchor();
@@ -27,9 +28,9 @@ namespace llvm {
     virtual ~MCWinCOFFObjectTargetWriter() {}
 
     unsigned getMachine() const { return Machine; }
-    virtual unsigned getRelocType(const MCValue &Target,
-                                  const MCFixup &Fixup,
-                                  bool IsCrossSection) const = 0;
+    virtual unsigned getRelocType(const MCValue &Target, const MCFixup &Fixup,
+                                  bool IsCrossSection,
+                                  const MCAsmBackend &MAB) const = 0;
     virtual bool recordRelocation(const MCFixup &) const { return true; }
   };
 
diff --git a/llvm/lib/MC/WinCOFFObjectWriter.cpp b/llvm/lib/MC/WinCOFFObjectWriter.cpp
index d8729bdbc4b..bd750af5de4 100644
--- a/llvm/lib/MC/WinCOFFObjectWriter.cpp
+++ b/llvm/lib/MC/WinCOFFObjectWriter.cpp
@@ -737,8 +737,9 @@ void WinCOFFObjectWriter::RecordRelocation(
   ++Reloc.Symb->Relocations;
 
   Reloc.Data.VirtualAddress += Fixup.getOffset();
-  Reloc.Data.Type = TargetObjectWriter->getRelocType(Target, Fixup,
-                                                     CrossSection);
+  Reloc.Data.Type =
+      TargetObjectWriter->getRelocType(Target, Fixup, CrossSection,
+                                       Asm.getBackend());
 
   // FIXME: Can anyone explain what this does other than adjust for the size
   // of the offset?
diff --git a/llvm/lib/Target/ARM/MCTargetDesc/ARMWinCOFFObjectWriter.cpp b/llvm/lib/Target/ARM/MCTargetDesc/ARMWinCOFFObjectWriter.cpp
index d31f1f41c69..2ee0e511b53 100644
--- a/llvm/lib/Target/ARM/MCTargetDesc/ARMWinCOFFObjectWriter.cpp
+++ b/llvm/lib/Target/ARM/MCTargetDesc/ARMWinCOFFObjectWriter.cpp
@@ -8,9 +8,12 @@
 //===----------------------------------------------------------------------===//
 
 #include "MCTargetDesc/ARMFixupKinds.h"
+#include "llvm/MC/MCAsmBackend.h"
 #include "llvm/MC/MCFixup.h"
+#include "llvm/MC/MCFixupKindInfo.h"
 #include "llvm/MC/MCValue.h"
 #include "llvm/MC/MCWinCOFFObjectWriter.h"
+#include "llvm/ADT/Twine.h"
 #include "llvm/Support/COFF.h"
 #include "llvm/Support/Debug.h"
 
@@ -26,14 +29,16 @@ public:
   virtual ~ARMWinCOFFObjectWriter() { }
 
   unsigned getRelocType(const MCValue &Target, const MCFixup &Fixup,
-                        bool IsCrossSection) const override;
+                        bool IsCrossSection,
+                        const MCAsmBackend &MAB) const override;
 
   bool recordRelocation(const MCFixup &) const override;
 };
 
 unsigned ARMWinCOFFObjectWriter::getRelocType(const MCValue &Target,
                                               const MCFixup &Fixup,
-                                              bool IsCrossSection) const {
+                                              bool IsCrossSection,
+                                              const MCAsmBackend &MAB) const {
   assert(getMachine() == COFF::IMAGE_FILE_MACHINE_ARMNT &&
          "AArch64 support not yet implemented");
 
@@ -41,7 +46,10 @@ unsigned ARMWinCOFFObjectWriter::getRelocType(const MCValue &Target,
     Target.isAbsolute() ? MCSymbolRefExpr::VK_None : Target.getSymA()->getKind();
 
   switch (static_cast<unsigned>(Fixup.getKind())) {
-  default: llvm_unreachable("unsupported relocation type");
+  default: {
+    const MCFixupKindInfo &Info = MAB.getFixupKindInfo(Fixup.getKind());
+    report_fatal_error(Twine("unsupported relocation type: ") + Info.Name);
+  }
   case FK_Data_4:
     switch (Modifier) {
     case MCSymbolRefExpr::VK_COFF_IMGREL32:
diff --git a/llvm/lib/Target/X86/MCTargetDesc/X86WinCOFFObjectWriter.cpp b/llvm/lib/Target/X86/MCTargetDesc/X86WinCOFFObjectWriter.cpp
index 40af822953c..e1df5c2d3c7 100644
--- a/llvm/lib/Target/X86/MCTargetDesc/X86WinCOFFObjectWriter.cpp
+++ b/llvm/lib/Target/X86/MCTargetDesc/X86WinCOFFObjectWriter.cpp
@@ -28,7 +28,8 @@ namespace {
     virtual ~X86WinCOFFObjectWriter();
 
     unsigned getRelocType(const MCValue &Target, const MCFixup &Fixup,
-                          bool IsCrossSection) const override;
+                          bool IsCrossSection,
+                          const MCAsmBackend &MAB) const override;
   };
 }
 
@@ -40,7 +41,8 @@ X86WinCOFFObjectWriter::~X86WinCOFFObjectWriter() {}
 
 unsigned X86WinCOFFObjectWriter::getRelocType(const MCValue &Target,
                                               const MCFixup &Fixup,
-                                              bool IsCrossSection) const {
+                                              bool IsCrossSection,
+                                              const MCAsmBackend &MAB) const {
   unsigned FixupKind = IsCrossSection ? FK_PCRel_4 : Fixup.getKind();
 
   MCSymbolRefExpr::VariantKind Modifier = Target.isAbsolute() ?
diff --git a/llvm/test/MC/ARM/Windows/invalid-relocation.s b/llvm/test/MC/ARM/Windows/invalid-relocation.s
new file mode 100644
index 00000000000..4f4c59839a6
--- /dev/null
+++ b/llvm/test/MC/ARM/Windows/invalid-relocation.s
@@ -0,0 +1,14 @@
+# RUN: not llvm-mc -triple thumbv7-windows -filetype obj -o /dev/null 2>&1 %s \
+# RUN:     | FileCheck %s
+
+	.def invalid_relocation
+		.type 32
+		.scl 2
+	.endef
+	.global invalid_relocation
+	.thumb_func
+invalid_relocation:
+	adr r0, invalid_relocation+1
+
+# CHECK: LLVM ERROR: unsupported relocation type: fixup_t2_adr_pcrel_12
+