1 files changed, 103 insertions, 0 deletions
diff --git a/lldb/source/Plugins/ABI/X86/ABISysV_i386.h b/lldb/source/Plugins/ABI/X86/ABISysV_i386.h
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index 000000000000..1ebb107d36df
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+++ b/lldb/source/Plugins/ABI/X86/ABISysV_i386.h
@@ -0,0 +1,103 @@
+//===------------------- ABISysV_i386.h -------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLDB_SOURCE_PLUGINS_ABI_X86_ABISYSV_I386_H
+#define LLDB_SOURCE_PLUGINS_ABI_X86_ABISYSV_I386_H
+
+#include "Plugins/ABI/X86/ABIX86.h"
+#include "lldb/lldb-private.h"
+
+class ABISysV_i386 : public ABIX86 {
+public:
+  ~ABISysV_i386() override = default;
+
+  size_t GetRedZoneSize() const override {
+    return 0; // There is no red zone for i386 Architecture
+  }
+
+  bool PrepareTrivialCall(lldb_private::Thread &thread, lldb::addr_t sp,
+                          lldb::addr_t functionAddress,
+                          lldb::addr_t returnAddress,
+                          llvm::ArrayRef<lldb::addr_t> args) const override;
+
+  bool GetArgumentValues(lldb_private::Thread &thread,
+                         lldb_private::ValueList &values) const override;
+
+  lldb_private::Status
+  SetReturnValueObject(lldb::StackFrameSP &frame_sp,
+                       lldb::ValueObjectSP &new_value) override;
+
+  lldb::ValueObjectSP
+  GetReturnValueObjectImpl(lldb_private::Thread &thread,
+                           lldb_private::CompilerType &type) const override;
+
+  bool
+  CreateFunctionEntryUnwindPlan(lldb_private::UnwindPlan &unwind_plan) override;
+
+  bool CreateDefaultUnwindPlan(lldb_private::UnwindPlan &unwind_plan) override;
+
+  bool RegisterIsVolatile(const lldb_private::RegisterInfo *reg_info) override {
+    return !RegisterIsCalleeSaved(reg_info);
+  }
+
+  // The SysV i386 ABI requires that stack frames be 16 byte aligned.
+  // When there is a trap handler on the stack, e.g. _sigtramp in userland
+  // code, we've seen that the stack pointer is often not aligned properly
+  // before the handler is invoked.  This means that lldb will stop the unwind
+  // early -- before the function which caused the trap.
+  //
+  // To work around this, we relax that alignment to be just word-size
+  // (4-bytes).
+  // Allowing the trap handlers for user space would be easy (_sigtramp) but
+  // in other environments there can be a large number of different functions
+  // involved in async traps.
+
+  // ToDo: When __m256 arguments are passed then stack frames should be
+  // 32 byte aligned. Decide what to do for 32 byte alignment checking
+  bool CallFrameAddressIsValid(lldb::addr_t cfa) override {
+    // Make sure the stack call frame addresses are 4 byte aligned
+    if (cfa & (4ull - 1ull))
+      return false; // Not 4 byte aligned
+    if (cfa == 0)
+      return false; // Zero is not a valid stack address
+    return true;
+  }
+
+  bool CodeAddressIsValid(lldb::addr_t pc) override {
+    // Check whether the address is a valid 32 bit address
+    return (pc <= UINT32_MAX);
+  }
+
+  // Static Functions
+
+  static void Initialize();
+
+  static void Terminate();
+
+  static lldb::ABISP CreateInstance(lldb::ProcessSP process_sp, const lldb_private::ArchSpec &arch);
+
+  // PluginInterface protocol
+
+  static lldb_private::ConstString GetPluginNameStatic();
+
+  lldb_private::ConstString GetPluginName() override;
+
+  uint32_t GetPluginVersion() override { return 1; }
+
+protected:
+  lldb::ValueObjectSP
+  GetReturnValueObjectSimple(lldb_private::Thread &thread,
+                             lldb_private::CompilerType &ast_type) const;
+
+  bool RegisterIsCalleeSaved(const lldb_private::RegisterInfo *reg_info);
+
+private:
+  using ABIX86::ABIX86; // Call CreateInstance instead.
+};
+
+#endif // LLDB_SOURCE_PLUGINS_ABI_X86_ABISYSV_I386_H