Adjust MD_CONTEXT_CPU_MASK to reflect reality, fix some code so it can handle dumps using the old value for MD_CONTEXT_ARM

The value of MD_CONTEXT_CPU_MASK in use assumes that only the lower 6 bits are used for flags, and the upper 26 bits are for the CPU type. However, as of Windows 7 SP1, the 7th bit is being used as a flag (per http://msdn.microsoft.com/en-us/library/hh134238%28v=vs.85%29.aspx and the Windows SDK headers). Adjusting MD_CONTEXT_CPU_MASK works, but unfortunately that masks off the existing value of MD_CONTEXT_ARM. This patch also changes the value of MD_CONTEXT_ARM and adjusts the minidump context reading machinery to gracefully handle minidumps with the old value.
R=mark at http://breakpad.appspot.com/302001

git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@831 4c0a9323-5329-0410-9bdc-e9ce6186880e

src/google_breakpad/common/minidump_cpu_amd64.h

@@ -201,8 +201,9 @@ typedef struct {
 } MDRawContextAMD64;  /* CONTEXT */
 
 /* For (MDRawContextAMD64).context_flags.  These values indicate the type of
- * context stored in the structure.  The high 26 bits identify the CPU, the
- * low 6 bits identify the type of context saved. */
+ * context stored in the structure.  The high 24 bits identify the CPU, the
+ * low 8 bits identify the type of context saved. */
+#define MD_CONTEXT_AMD64 0x00100000  /* CONTEXT_AMD64 */
 #define MD_CONTEXT_AMD64_CONTROL         (MD_CONTEXT_AMD64 | 0x00000001)
      /* CONTEXT_CONTROL */
 #define MD_CONTEXT_AMD64_INTEGER         (MD_CONTEXT_AMD64 | 0x00000002)
@@ -213,6 +214,9 @@ typedef struct {
      /* CONTEXT_FLOATING_POINT */
 #define MD_CONTEXT_AMD64_DEBUG_REGISTERS (MD_CONTEXT_AMD64 | 0x00000010)
      /* CONTEXT_DEBUG_REGISTERS */
+#define MD_CONTEXT_AMD64_XSTATE          (MD_CONTEXT_AMD64 | 0x00000040)
+     /* CONTEXT_XSTATE */
+
 /* WinNT.h refers to CONTEXT_MMX_REGISTERS but doesn't appear to define it
  * I think it really means CONTEXT_FLOATING_POINT.
  */

src/google_breakpad/common/minidump_cpu_arm.h

@@ -128,6 +128,16 @@ enum MDARMRegisterNumbers {
 
 /* For (MDRawContextARM).context_flags.  These values indicate the type of
  * context stored in the structure. */
+/* CONTEXT_ARM from the Windows CE 5.0 SDK. This value isn't correct
+ * because this bit can be used for flags. Presumably this value was
+ * never actually used in minidumps, but only in "CEDumps" which
+ * are a whole parallel minidump file format for Windows CE.
+ * Therefore, Breakpad defines its own value for ARM CPUs.
+ */
+#define MD_CONTEXT_ARM_OLD               0x00000040
+/* This value was chosen to avoid likely conflicts with MD_CONTEXT_*
+ * for other CPUs. */
+#define MD_CONTEXT_ARM                   0x40000000
 #define MD_CONTEXT_ARM_INTEGER           (MD_CONTEXT_ARM | 0x00000002)
 #define MD_CONTEXT_ARM_FLOATING_POINT    (MD_CONTEXT_ARM | 0x00000004)
 

src/google_breakpad/common/minidump_cpu_x86.h

@@ -141,8 +141,8 @@ typedef struct {
 } MDRawContextX86;  /* CONTEXT */
 
 /* For (MDRawContextX86).context_flags.  These values indicate the type of
- * context stored in the structure.  The high 26 bits identify the CPU, the
- * low 6 bits identify the type of context saved. */
+ * context stored in the structure.  The high 24 bits identify the CPU, the
+ * low 8 bits identify the type of context saved. */
 #define MD_CONTEXT_X86                    0x00010000
      /* CONTEXT_i386, CONTEXT_i486: identifies CPU */
 #define MD_CONTEXT_X86_CONTROL            (MD_CONTEXT_X86 | 0x00000001)
@@ -157,6 +157,8 @@ typedef struct {
      /* CONTEXT_DEBUG_REGISTERS */
 #define MD_CONTEXT_X86_EXTENDED_REGISTERS (MD_CONTEXT_X86 | 0x00000020)
      /* CONTEXT_EXTENDED_REGISTERS */
+#define MD_CONTEXT_X86_XSTATE             (MD_CONTEXT_X86 | 0x00000040)
+     /* CONTEXT_XSTATE */
 
 #define MD_CONTEXT_X86_FULL              (MD_CONTEXT_X86_CONTROL | \
                                           MD_CONTEXT_X86_INTEGER | \

src/google_breakpad/common/minidump_format.h

@@ -90,19 +90,20 @@ typedef struct {
  * WinNT.h
  */
 
-/* Non-x86 CPU identifiers found in the high 26 bits of
+/* Non-x86 CPU identifiers found in the high 24 bits of
  * (MDRawContext*).context_flags.  These aren't used by Breakpad, but are
  * defined here for reference, to avoid assigning values that conflict
  * (although some values already conflict). */
 #define MD_CONTEXT_IA64  0x00080000  /* CONTEXT_IA64 */
-#define MD_CONTEXT_AMD64 0x00100000  /* CONTEXT_AMD64 */
 /* Additional values from winnt.h in the Windows CE 5.0 SDK: */
 #define MD_CONTEXT_SHX   0x000000c0  /* CONTEXT_SH4 (Super-H, includes SH3) */
-#define MD_CONTEXT_ARM   0x00000040  /* CONTEXT_ARM (0x40 bit set in SHx?) */
 #define MD_CONTEXT_MIPS  0x00010000  /* CONTEXT_R4000 (same value as x86?) */
 #define MD_CONTEXT_ALPHA 0x00020000  /* CONTEXT_ALPHA */
 
-#define MD_CONTEXT_CPU_MASK 0xffffffc0
+/* As of Windows 7 SP1, the number of flag bits has increased to
+ * include 0x40 (CONTEXT_XSTATE):
+ * http://msdn.microsoft.com/en-us/library/hh134238%28v=vs.85%29.aspx */
+#define MD_CONTEXT_CPU_MASK 0xffffff00
 
 
 /* This is a base type for MDRawContextX86 and MDRawContextPPC.  This