Re-commit "Modernize NativeProcessProtocol::GetSoftwareBreakpointTrapOpcode"

This recommits r341487, which was reverted due to failing tests with
clang. It turned out I had incorrectly expected that the literal arrays
passed to ArrayRef constructor will have static (permanent) storage.
This was only the case with gcc, while clang was constructing them on
stack, leading to dangling pointers when the function returns.

The fix is to explicitly assign static storage duration to the opcode
arrays.

llvm-svn: 341758

2 files changed, 13 insertions, 66 deletions

diff --git a/lldb/source/Plugins/Process/Linux/NativeProcessLinux.cpp b/lldb/source/Plugins/Process/Linux/NativeProcessLinux.cpp
index b474e12d071..3fa888c1cc4 100644
--- a/lldb/source/Plugins/Process/Linux/NativeProcessLinux.cpp
+++ b/lldb/source/Plugins/Process/Linux/NativeProcessLinux.cpp
@@ -1551,74 +1551,26 @@ Status NativeProcessLinux::RemoveBreakpoint(lldb::addr_t addr, bool hardware) {
     return NativeProcessProtocol::RemoveBreakpoint(addr);
 }
 
-Status NativeProcessLinux::GetSoftwareBreakpointTrapOpcode(
-    size_t trap_opcode_size_hint, size_t &actual_opcode_size,
-    const uint8_t *&trap_opcode_bytes) {
-  // FIXME put this behind a breakpoint protocol class that can be set per
-  // architecture.  Need MIPS support here.
-  static const uint8_t g_aarch64_opcode[] = {0x00, 0x00, 0x20, 0xd4};
+llvm::Expected<llvm::ArrayRef<uint8_t>>
+NativeProcessLinux::GetSoftwareBreakpointTrapOpcode(size_t size_hint) {
   // The ARM reference recommends the use of 0xe7fddefe and 0xdefe but the
   // linux kernel does otherwise.
-  static const uint8_t g_arm_breakpoint_opcode[] = {0xf0, 0x01, 0xf0, 0xe7};
-  static const uint8_t g_i386_opcode[] = {0xCC};
-  static const uint8_t g_mips64_opcode[] = {0x00, 0x00, 0x00, 0x0d};
-  static const uint8_t g_mips64el_opcode[] = {0x0d, 0x00, 0x00, 0x00};
-  static const uint8_t g_s390x_opcode[] = {0x00, 0x01};
-  static const uint8_t g_thumb_breakpoint_opcode[] = {0x01, 0xde};
-  static const uint8_t g_ppc64le_opcode[] = {0x08, 0x00, 0xe0, 0x7f}; // trap
-
-  switch (m_arch.GetMachine()) {
-  case llvm::Triple::aarch64:
-    trap_opcode_bytes = g_aarch64_opcode;
-    actual_opcode_size = sizeof(g_aarch64_opcode);
-    return Status();
+  static const uint8_t g_arm_opcode[] = {0xf0, 0x01, 0xf0, 0xe7};
+  static const uint8_t g_thumb_opcode[] = {0x01, 0xde};
 
+  switch (GetArchitecture().GetMachine()) {
   case llvm::Triple::arm:
-    switch (trap_opcode_size_hint) {
+    switch (size_hint) {
     case 2:
-      trap_opcode_bytes = g_thumb_breakpoint_opcode;
-      actual_opcode_size = sizeof(g_thumb_breakpoint_opcode);
-      return Status();
+      return g_thumb_opcode;
     case 4:
-      trap_opcode_bytes = g_arm_breakpoint_opcode;
-      actual_opcode_size = sizeof(g_arm_breakpoint_opcode);
-      return Status();
+      return g_arm_opcode;
     default:
-      assert(false && "Unrecognised trap opcode size hint!");
-      return Status("Unrecognised trap opcode size hint!");
+      return llvm::createStringError(llvm::inconvertibleErrorCode(),
+                                     "Unrecognised trap opcode size hint!");
     }
-
-  case llvm::Triple::x86:
-  case llvm::Triple::x86_64:
-    trap_opcode_bytes = g_i386_opcode;
-    actual_opcode_size = sizeof(g_i386_opcode);
-    return Status();
-
-  case llvm::Triple::mips:
-  case llvm::Triple::mips64:
-    trap_opcode_bytes = g_mips64_opcode;
-    actual_opcode_size = sizeof(g_mips64_opcode);
-    return Status();
-
-  case llvm::Triple::mipsel:
-  case llvm::Triple::mips64el:
-    trap_opcode_bytes = g_mips64el_opcode;
-    actual_opcode_size = sizeof(g_mips64el_opcode);
-    return Status();
-
-  case llvm::Triple::systemz:
-    trap_opcode_bytes = g_s390x_opcode;
-    actual_opcode_size = sizeof(g_s390x_opcode);
-    return Status();
-
-  case llvm::Triple::ppc64le:
-    trap_opcode_bytes = g_ppc64le_opcode;
-    actual_opcode_size = sizeof(g_ppc64le_opcode);
-    return Status();
-
   default:
-    assert(false && "CPU type not supported!");
-    return Status("CPU type not supported");
+    return NativeProcessProtocol::GetSoftwareBreakpointTrapOpcode(size_hint);
   }
 }
 
diff --git a/lldb/source/Plugins/Process/Linux/NativeProcessLinux.h b/lldb/source/Plugins/Process/Linux/NativeProcessLinux.h
index 1c2f786e8d6..97ad5711ff1 100644
--- a/lldb/source/Plugins/Process/Linux/NativeProcessLinux.h
+++ b/lldb/source/Plugins/Process/Linux/NativeProcessLinux.h
@@ -134,13 +134,8 @@ public:
   bool SupportHardwareSingleStepping() const;
 
 protected:
-  // ---------------------------------------------------------------------
-  // NativeProcessProtocol protected interface
-  // ---------------------------------------------------------------------
-  Status
-  GetSoftwareBreakpointTrapOpcode(size_t trap_opcode_size_hint,
-                                  size_t &actual_opcode_size,
-                                  const uint8_t *&trap_opcode_bytes) override;
+  llvm::Expected<llvm::ArrayRef<uint8_t>>
+  GetSoftwareBreakpointTrapOpcode(size_t size_hint) override;
 
 private:
   MainLoop::SignalHandleUP m_sigchld_handle;