From 9c00ddb8d5c6be2286a3a66ccec6c6ecc682295b Mon Sep 17 00:00:00 2001
From: Saleem Abdulrasool <compnerd@compnerd.org>
Date: Thu, 18 Sep 2014 04:28:29 +0000
Subject: [PATCH] ARM: prevent crash on ELF directives on COFF

Certain directives are unsupported on Windows (some of which could/should be
supported).  We would not diagnose the use but rather crash during the emission
as we try to access the Target Streamer.  Add an assertion to prevent creating a
NULL reference (which is not permitted under C++) as well as a test to ensure
that we can diagnose the disabled directives.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218014 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/ARM/AsmParser/ARMAsmParser.cpp |  5 +-
 test/MC/ARM/directive-unsupported.s       | 68 +++++++++++++++++++++++
 2 files changed, 72 insertions(+), 1 deletion(-)
 create mode 100644 test/MC/ARM/directive-unsupported.s

diff --git a/lib/Target/ARM/AsmParser/ARMAsmParser.cpp b/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
index 2243da03e28..7e33ec5617d 100644
--- a/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
+++ b/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
@@ -135,6 +135,8 @@ class ARMAsmParser : public MCTargetAsmParser {
   UnwindContext UC;
 
   ARMTargetStreamer &getTargetStreamer() {
+    assert(getParser().getStreamer().getTargetStreamer() &&
+           "do not have a target streamer");
     MCTargetStreamer &TS = *getParser().getStreamer().getTargetStreamer();
     return static_cast<ARMTargetStreamer &>(TS);
   }
@@ -8313,6 +8315,7 @@ bool ARMAsmParser::ParseDirective(AsmToken DirectiveID) {
   const MCObjectFileInfo::Environment Format =
     getContext().getObjectFileInfo()->getObjectFileType();
   bool IsMachO = Format == MCObjectFileInfo::IsMachO;
+  bool IsCOFF = Format == MCObjectFileInfo::IsCOFF;
 
   StringRef IDVal = DirectiveID.getIdentifier();
   if (IDVal == ".word")
@@ -8364,7 +8367,7 @@ bool ARMAsmParser::ParseDirective(AsmToken DirectiveID) {
   else if (IDVal == ".thumb_set")
     return parseDirectiveThumbSet(DirectiveID.getLoc());
 
-  if (!IsMachO) {
+  if (!IsMachO && !IsCOFF) {
     if (IDVal == ".arch")
       return parseDirectiveArch(DirectiveID.getLoc());
     else if (IDVal == ".cpu")
diff --git a/test/MC/ARM/directive-unsupported.s b/test/MC/ARM/directive-unsupported.s
new file mode 100644
index 00000000000..0b1f9bac61a
--- /dev/null
+++ b/test/MC/ARM/directive-unsupported.s
@@ -0,0 +1,68 @@
+@ RUN: not llvm-mc -triple thumbv7-windows -filetype asm -o /dev/null %s 2>&1 \
+@ RUN:     | FileCheck %s
+
+@ RUN: not llvm-mc -triple armv7-darwin -filetype asm -o /dev/null %s 2>&1 \
+@ RUN:    | FileCheck %s
+
+	.syntax unified
+
+	.arch armv7
+
+// CHECK: error: unknown directive
+// CHECK: .arch armv7
+// CHECK: ^
+
+	.cpu cortex-a7
+
+// CHECK: error: unknown directive
+// CHECK: .cpu cortex-a7
+// CHECK: ^
+
+	.fpu neon
+
+// CHECK: error: unknown directive
+// CHECK: .fpu neon
+// CHECK: ^
+
+	.eabi_attribute 0, 0
+
+// CHECK: error: unknown directive
+// CHECK: .eabi_attribute 0, 0
+// CHECK: ^
+
+	.inst 0xdefe
+
+// CHECK: error: unknown directive
+// CHECK: .inst 0xdefe
+// CHECK: ^
+
+	.inst.n 0xdefe
+
+// CHECK: error: unknown directive
+// CHECK: .inst.n 0xdefe
+// CHECK: ^
+
+	.inst.w 0xdefe
+
+// CHECK: error: unknown directive
+// CHECK: .inst.w 0xdefe
+// CHECK: ^
+
+	.object_arch armv7
+
+// CHECK: error: unknown directive
+// CHECK: .object_arch armv7
+// CHECK: ^
+
+	.tlsdescseq undefined
+
+// CHECK: error: unknown directive
+// CHECK: .tlsdescseq undefined
+// CHECK: ^
+
+	.fnstart
+
+// CHECK: error: unknown directive
+// CHECK: .fnstart
+// CHECK: ^
+