Imported Upstream version 5.18.0.179

Former-commit-id: 67aa10e65b237e1c4537630979ee99ebe1374215

external/llvm/lib/CodeGen/SafeStackLayout.h

@@ -0,0 +1,80 @@
+//===- SafeStackLayout.h - SafeStack frame layout --------------*- C++ -*--===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIB_CODEGEN_SAFESTACKLAYOUT_H
+#define LLVM_LIB_CODEGEN_SAFESTACKLAYOUT_H
+
+#include "SafeStackColoring.h"
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/SmallVector.h"
+
+namespace llvm {
+
+class raw_ostream;
+class Value;
+
+namespace safestack {
+
+/// Compute the layout of an unsafe stack frame.
+class StackLayout {
+  unsigned MaxAlignment;
+
+  struct StackRegion {
+    unsigned Start;
+    unsigned End;
+    StackColoring::LiveRange Range;
+
+    StackRegion(unsigned Start, unsigned End,
+                const StackColoring::LiveRange &Range)
+        : Start(Start), End(End), Range(Range) {}
+  };
+
+  /// The list of current stack regions, sorted by StackRegion::Start.
+  SmallVector<StackRegion, 16> Regions;
+
+  struct StackObject {
+    const Value *Handle;
+    unsigned Size, Alignment;
+    StackColoring::LiveRange Range;
+  };
+
+  SmallVector<StackObject, 8> StackObjects;
+
+  DenseMap<const Value *, unsigned> ObjectOffsets;
+
+  void layoutObject(StackObject &Obj);
+
+public:
+  StackLayout(unsigned StackAlignment) : MaxAlignment(StackAlignment) {}
+
+  /// Add an object to the stack frame. Value pointer is opaque and used as a
+  /// handle to retrieve the object's offset in the frame later.
+  void addObject(const Value *V, unsigned Size, unsigned Alignment,
+                 const StackColoring::LiveRange &Range);
+
+  /// Run the layout computation for all previously added objects.
+  void computeLayout();
+
+  /// Returns the offset to the object start in the stack frame.
+  unsigned getObjectOffset(const Value *V) { return ObjectOffsets[V]; }
+
+  /// Returns the size of the entire frame.
+  unsigned getFrameSize() { return Regions.empty() ? 0 : Regions.back().End; }
+
+  /// Returns the alignment of the frame.
+  unsigned getFrameAlignment() { return MaxAlignment; }
+
+  void print(raw_ostream &OS);
+};
+
+} // end namespace safestack
+
+} // end namespace llvm
+
+#endif // LLVM_LIB_CODEGEN_SAFESTACKLAYOUT_H