Reland [AArch64][DebugInfo] Do not recompute CalleeSavedStackSize (Take 2)

Fixed up test/DebugInfo/MIR/Mips/live-debug-values-reg-copy.mir that
broke r375425.

1 files changed, 50 insertions, 2 deletions

diff --git a/llvm/lib/Target/AArch64/AArch64MachineFunctionInfo.h b/llvm/lib/Target/AArch64/AArch64MachineFunctionInfo.h
index 0009fb7b552..32661860934 100644
--- a/llvm/lib/Target/AArch64/AArch64MachineFunctionInfo.h
+++ b/llvm/lib/Target/AArch64/AArch64MachineFunctionInfo.h
@@ -55,6 +55,7 @@ class AArch64FunctionInfo final : public MachineFunctionInfo {
 
   /// Amount of stack frame size used for saving callee-saved registers.
   unsigned CalleeSavedStackSize;
+  bool HasCalleeSavedStackSize = false;
 
   /// Number of TLS accesses using the special (combinable)
   /// _TLS_MODULE_BASE_ symbol.
@@ -167,8 +168,55 @@ public:
   void setLocalStackSize(unsigned Size) { LocalStackSize = Size; }
   unsigned getLocalStackSize() const { return LocalStackSize; }
 
-  void setCalleeSavedStackSize(unsigned Size) { CalleeSavedStackSize = Size; }
-  unsigned getCalleeSavedStackSize() const { return CalleeSavedStackSize; }
+  void setCalleeSavedStackSize(unsigned Size) {
+    CalleeSavedStackSize = Size;
+    HasCalleeSavedStackSize = true;
+  }
+
+  // When CalleeSavedStackSize has not been set (for example when
+  // some MachineIR pass is run in isolation), then recalculate
+  // the CalleeSavedStackSize directly from the CalleeSavedInfo.
+  // Note: This information can only be recalculated after PEI
+  // has assigned offsets to the callee save objects.
+  unsigned getCalleeSavedStackSize(const MachineFrameInfo &MFI) const {
+    bool ValidateCalleeSavedStackSize = false;
+
+#ifndef NDEBUG
+    // Make sure the calculated size derived from the CalleeSavedInfo
+    // equals the cached size that was calculated elsewhere (e.g. in
+    // determineCalleeSaves).
+    ValidateCalleeSavedStackSize = HasCalleeSavedStackSize;
+#endif
+
+    if (!HasCalleeSavedStackSize || ValidateCalleeSavedStackSize) {
+      assert(MFI.isCalleeSavedInfoValid() && "CalleeSavedInfo not calculated");
+      if (MFI.getCalleeSavedInfo().empty())
+        return 0;
+
+      int64_t MinOffset = std::numeric_limits<int64_t>::max();
+      int64_t MaxOffset = std::numeric_limits<int64_t>::min();
+      for (const auto &Info : MFI.getCalleeSavedInfo()) {
+        int FrameIdx = Info.getFrameIdx();
+        int64_t Offset = MFI.getObjectOffset(FrameIdx);
+        int64_t ObjSize = MFI.getObjectSize(FrameIdx);
+        MinOffset = std::min<int64_t>(Offset, MinOffset);
+        MaxOffset = std::max<int64_t>(Offset + ObjSize, MaxOffset);
+      }
+
+      unsigned Size = alignTo(MaxOffset - MinOffset, 16);
+      assert((!HasCalleeSavedStackSize || getCalleeSavedStackSize() == Size) &&
+             "Invalid size calculated for callee saves");
+      return Size;
+    }
+
+    return getCalleeSavedStackSize();
+  }
+
+  unsigned getCalleeSavedStackSize() const {
+    assert(HasCalleeSavedStackSize &&
+           "CalleeSavedStackSize has not been calculated");
+    return CalleeSavedStackSize;
+  }
 
   void incNumLocalDynamicTLSAccesses() { ++NumLocalDynamicTLSAccesses; }
   unsigned getNumLocalDynamicTLSAccesses() const {