Added crash context float state flag

Instead of listing everywhere the set of architectures that do not
require/support explicit float state in their crash context, a new
GOOGLE_BREAKPAD_CRASH_CONTEXT_HAS_FLOAT_STATE preprocessor macro has
been defined.

Adding novel architectures will only require to manage the
macro definition in a single place.

Change-Id: I2732982f2cdfc9fcd2f71d6e5e122617faff9e82
Reviewed-on: https://chromium-review.googlesource.com/c/breakpad/breakpad/+/3876345
Reviewed-by: Mike Frysinger <vapier@chromium.org>

src/client/linux/handler/exception_handler.cc

@@ -461,7 +461,7 @@ bool ExceptionHandler::HandleSignal(int /*sig*/, siginfo_t* info, void* uc) {
     memcpy(&g_crash_context_.float_state, fp_ptr,
            sizeof(g_crash_context_.float_state));
   }
-#elif !defined(__ARM_EABI__) && !defined(__mips__)
+#elif GOOGLE_BREAKPAD_CRASH_CONTEXT_HAS_FLOAT_STATE
   // FP state is not part of user ABI on ARM Linux.
   // In case of MIPS Linux FP state is already part of ucontext_t
   // and 'float_state' is not a member of CrashContext.
@@ -701,7 +701,7 @@ bool ExceptionHandler::WriteMinidump() {
   }
 #endif
 
-#if !defined(__ARM_EABI__) && !defined(__aarch64__) && !defined(__mips__)
+#if GOOGLE_BREAKPAD_CRASH_CONTEXT_HAS_FLOAT_STATE && !defined(__aarch64__)
   // FPU state is not part of ARM EABI ucontext_t.
   memcpy(&context.float_state, context.context.uc_mcontext.fpregs,
          sizeof(context.float_state));

src/client/linux/handler/exception_handler.h

@@ -44,6 +44,15 @@
 #include "common/using_std_string.h"
 #include "google_breakpad/common/minidump_format.h"
 
+#if !defined(__ARM_EABI__) && !defined(__mips__)
+// FP state is not part of user ABI for Linux ARM.
+// In case of MIPS and RISCV Linux FP state is already part of ucontext_t
+// so 'float_state' is not required.
+# define GOOGLE_BREAKPAD_CRASH_CONTEXT_HAS_FLOAT_STATE 1
+#else
+# define GOOGLE_BREAKPAD_CRASH_CONTEXT_HAS_FLOAT_STATE 0
+#endif
+
 namespace google_breakpad {
 
 // ExceptionHandler
@@ -192,10 +201,7 @@ class ExceptionHandler {
     siginfo_t siginfo;
     pid_t tid;  // the crashing thread.
     ucontext_t context;
-#if !defined(__ARM_EABI__) && !defined(__mips__)
+#if GOOGLE_BREAKPAD_CRASH_CONTEXT_HAS_FLOAT_STATE
-    // #ifdef this out because FP state is not part of user ABI for Linux ARM.
-    // In case of MIPS Linux FP state is already part of ucontext_t so
-    // 'float_state' is not required.
     fpstate_t float_state;
 #endif
   };

src/client/linux/microdump_writer/microdump_writer.cc

@@ -138,7 +138,7 @@ class MicrodumpWriter {
                   const MicrodumpExtraInfo& microdump_extra_info,
                   LinuxDumper* dumper)
       : ucontext_(context ? &context->context : NULL),
-#if !defined(__ARM_EABI__) && !defined(__mips__)
+#if GOOGLE_BREAKPAD_CRASH_CONTEXT_HAS_FLOAT_STATE
         float_state_(context ? &context->float_state : NULL),
 #endif
         dumper_(dumper),
@@ -409,7 +409,7 @@ class MicrodumpWriter {
   void DumpCPUState() {
     RawContextCPU cpu;
     my_memset(&cpu, 0, sizeof(RawContextCPU));
-#if !defined(__ARM_EABI__) && !defined(__mips__)
+#if GOOGLE_BREAKPAD_CRASH_CONTEXT_HAS_FLOAT_STATE
     UContextReader::FillCPUContext(&cpu, ucontext_, float_state_);
 #else
     UContextReader::FillCPUContext(&cpu, ucontext_);
@@ -605,7 +605,7 @@ class MicrodumpWriter {
   void* Alloc(unsigned bytes) { return dumper_->allocator()->Alloc(bytes); }
 
   const ucontext_t* const ucontext_;
-#if !defined(__ARM_EABI__) && !defined(__mips__)
+#if GOOGLE_BREAKPAD_CRASH_CONTEXT_HAS_FLOAT_STATE
   const google_breakpad::fpstate_t* const float_state_;
 #endif
   LinuxDumper* dumper_;

src/client/linux/minidump_writer/minidump_writer.cc

@@ -141,7 +141,7 @@ class MinidumpWriter {
       : fd_(minidump_fd),
         path_(minidump_path),
         ucontext_(context ? &context->context : NULL),
-#if !defined(__ARM_EABI__) && !defined(__mips__)
+#if GOOGLE_BREAKPAD_CRASH_CONTEXT_HAS_FLOAT_STATE
         float_state_(context ? &context->float_state : NULL),
 #endif
         dumper_(dumper),
@@ -473,7 +473,7 @@ class MinidumpWriter {
         if (!cpu.Allocate())
           return false;
         my_memset(cpu.get(), 0, sizeof(RawContextCPU));
-#if !defined(__ARM_EABI__) && !defined(__mips__)
+#if GOOGLE_BREAKPAD_CRASH_CONTEXT_HAS_FLOAT_STATE
         UContextReader::FillCPUContext(cpu.get(), ucontext_, float_state_);
 #else
         UContextReader::FillCPUContext(cpu.get(), ucontext_);
@@ -1386,7 +1386,7 @@ class MinidumpWriter {
   const char* path_;  // Path to the file where the minidum should be written.
 
   const ucontext_t* const ucontext_;  // also from the signal handler
-#if !defined(__ARM_EABI__) && !defined(__mips__)
+#if GOOGLE_BREAKPAD_CRASH_CONTEXT_HAS_FLOAT_STATE
   const google_breakpad::fpstate_t* const float_state_;  // ditto
 #endif
   LinuxDumper* dumper_;