From 9bb386a9330f9c26f648ce1009561833fbc59e4b Mon Sep 17 00:00:00 2001
From: Johnny Chen <johnny.chen@apple.com>
Date: Wed, 13 Apr 2011 19:46:05 +0000
Subject: [PATCH] Check the corner cases for t2LDRSHi12 correctly and mark
 invalid encodings as such.

rdar://problem/9276651


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@129462 91177308-0d34-0410-b5e6-96231b3b80d8
---
 .../ARM/Disassembler/ThumbDisassemblerCore.h  | 34 ++++++++++++++++++-
 .../ARM/invalid-t2LDRSHi12-thumb.txt          | 10 ++++++
 .../ARM/invalid-t2LDRSHi8-thumb.txt           | 10 ++++++
 3 files changed, 53 insertions(+), 1 deletion(-)
 create mode 100644 test/MC/Disassembler/ARM/invalid-t2LDRSHi12-thumb.txt
 create mode 100644 test/MC/Disassembler/ARM/invalid-t2LDRSHi8-thumb.txt

diff --git a/lib/Target/ARM/Disassembler/ThumbDisassemblerCore.h b/lib/Target/ARM/Disassembler/ThumbDisassemblerCore.h
index f80c92a683c..71451e3e2e7 100644
--- a/lib/Target/ARM/Disassembler/ThumbDisassemblerCore.h
+++ b/lib/Target/ARM/Disassembler/ThumbDisassemblerCore.h
@@ -1920,6 +1920,38 @@ static bool BadRegsThumb2LdSt(unsigned Opcode, uint32_t insn, bool Load,
       DEBUG(errs() << "if t == 13 then UNPREDICTABLE\n");
       return true;
     }
+    // A6.3.8 Load halfword, memory hints
+    const StringRef Name = ARMInsts[Opcode].Name;
+    if (Name.startswith("t2LDRH") || Name.startswith("t2LDRSH")) {
+      if (WB) {
+        if (R0 == R1)  {
+          // A8.6.82 LDRSH (immediate) Encoding T2
+          DEBUG(errs() << "if WB && n == t then UNPREDICTABLE\n");
+          return true;
+        }
+        if (R0 == 15 && slice(insn, 10, 8) == 3)  {
+          // A8.6.82 LDRSH (immediate) Encoding T2 (errata markup 8.0)
+          DEBUG(errs() << "if t == 15 && PUW == '011' then UNPREDICTABLE\n");
+          return true;
+        }
+      } else {
+        if (Opcode == ARM::t2LDRHi8 || Opcode == ARM::t2LDRSHi8) {
+          if (R0 == 15 && slice(insn, 10, 8) == 4) {
+            // A8.6.82 LDRSH (immediate) Encoding T2
+            DEBUG(errs() << "if Rt == '1111' and PUW == '100' then SEE"
+                         << " \"Unallocated memory hints\"\n");
+            return true;
+          }
+        } else {
+          if (R0 == 15) {
+            // A8.6.82 LDRSH (immediate) Encoding T1
+            DEBUG(errs() << "if Rt == '1111' then SEE"
+                         << " \"Unallocated memory hints\"\n");
+            return true;
+          }
+        }
+      }
+    }
   } else {
     if (WB && R0 == R1) {
       DEBUG(errs() << "if wback && n == t then UNPREDICTABLE\n");
@@ -1998,7 +2030,7 @@ static bool DisassembleThumb2LdSt(bool Load, MCInst &MI, unsigned Opcode,
   bool Imm12 = !ThreeReg && slice(insn, 23, 23) == 1; // ARMInstrThumb2.td
 
   // Build the register operands, followed by the immediate.
-  unsigned R0, R1, R2 = 0;
+  unsigned R0 = 0, R1 = 0, R2 = 0;
   unsigned Rd = decodeRd(insn);
   int Imm = 0;
 
diff --git a/test/MC/Disassembler/ARM/invalid-t2LDRSHi12-thumb.txt b/test/MC/Disassembler/ARM/invalid-t2LDRSHi12-thumb.txt
new file mode 100644
index 00000000000..a501eb9cd54
--- /dev/null
+++ b/test/MC/Disassembler/ARM/invalid-t2LDRSHi12-thumb.txt
@@ -0,0 +1,10 @@
+# RUN: llvm-mc --disassemble %s -triple=thumb-apple-darwin9 |& grep {invalid instruction encoding}
+
+# Opcode=1953 Name=t2LDRSHi12 Format=ARM_FORMAT_THUMBFRM(25)
+#  31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10  9  8  7  6  5  4  3  2  1  0 
+# -------------------------------------------------------------------------------------------------
+# | 1: 1: 1: 1| 1: 0: 0: 1| 1: 0: 1: 1| 0: 0: 1: 1| 1: 1: 1: 1| 1: 0: 0: 0| 1: 1: 0: 1| 1: 1: 1: 1|
+# -------------------------------------------------------------------------------------------------
+# 
+# if Rt = '1111' then SEE "Unallocated memory hints"
+0xb3 0xf9 0xdf 0xf8
diff --git a/test/MC/Disassembler/ARM/invalid-t2LDRSHi8-thumb.txt b/test/MC/Disassembler/ARM/invalid-t2LDRSHi8-thumb.txt
new file mode 100644
index 00000000000..f886a6f074b
--- /dev/null
+++ b/test/MC/Disassembler/ARM/invalid-t2LDRSHi8-thumb.txt
@@ -0,0 +1,10 @@
+# RUN: llvm-mc --disassemble %s -triple=thumb-apple-darwin9 |& grep {invalid instruction encoding}
+
+# Opcode=1954 Name=t2LDRSHi8 Format=ARM_FORMAT_THUMBFRM(25)
+#  31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10  9  8  7  6  5  4  3  2  1  0 
+# -------------------------------------------------------------------------------------------------
+# | 1: 1: 1: 1| 1: 0: 0: 1| 0: 0: 1: 1| 0: 1: 0: 1| 1: 1: 1: 1| 1: 1: 0: 0| 0: 0: 0: 0| 0: 0: 0: 0|
+# -------------------------------------------------------------------------------------------------
+# 
+# if Rt == '1111' and PUW == '100' then SEE "Unallocated memory hints"
+0x35 0xf9 0x00 0xfc
-- 
2.34.1