1 files changed, 103 insertions, 0 deletions
diff --git a/llvm/lib/Analysis/AliasAnalysisSummary.cpp b/llvm/lib/Analysis/AliasAnalysisSummary.cpp
new file mode 100644
index 0000000000000..2f3396a44117a
--- /dev/null
+++ b/llvm/lib/Analysis/AliasAnalysisSummary.cpp
@@ -0,0 +1,103 @@
+#include "AliasAnalysisSummary.h"
+#include "llvm/IR/Argument.h"
+#include "llvm/IR/Type.h"
+#include "llvm/Support/Compiler.h"
+
+namespace llvm {
+namespace cflaa {
+
+namespace {
+const unsigned AttrEscapedIndex = 0;
+const unsigned AttrUnknownIndex = 1;
+const unsigned AttrGlobalIndex = 2;
+const unsigned AttrCallerIndex = 3;
+const unsigned AttrFirstArgIndex = 4;
+const unsigned AttrLastArgIndex = NumAliasAttrs;
+const unsigned AttrMaxNumArgs = AttrLastArgIndex - AttrFirstArgIndex;
+
+// It would be *slightly* prettier if we changed these to AliasAttrs, but it
+// seems that both GCC and MSVC emit dynamic initializers for const bitsets.
+using AliasAttr = unsigned;
+const AliasAttr AttrNone = 0;
+const AliasAttr AttrEscaped = 1 << AttrEscapedIndex;
+const AliasAttr AttrUnknown = 1 << AttrUnknownIndex;
+const AliasAttr AttrGlobal = 1 << AttrGlobalIndex;
+const AliasAttr AttrCaller = 1 << AttrCallerIndex;
+const AliasAttr ExternalAttrMask = AttrEscaped | AttrUnknown | AttrGlobal;
+}
+
+AliasAttrs getAttrNone() { return AttrNone; }
+
+AliasAttrs getAttrUnknown() { return AttrUnknown; }
+bool hasUnknownAttr(AliasAttrs Attr) { return Attr.test(AttrUnknownIndex); }
+
+AliasAttrs getAttrCaller() { return AttrCaller; }
+bool hasCallerAttr(AliasAttrs Attr) { return Attr.test(AttrCaller); }
+bool hasUnknownOrCallerAttr(AliasAttrs Attr) {
+  return Attr.test(AttrUnknownIndex) || Attr.test(AttrCallerIndex);
+}
+
+AliasAttrs getAttrEscaped() { return AttrEscaped; }
+bool hasEscapedAttr(AliasAttrs Attr) { return Attr.test(AttrEscapedIndex); }
+
+static AliasAttr argNumberToAttr(unsigned ArgNum) {
+  if (ArgNum >= AttrMaxNumArgs)
+    return AttrUnknown;
+  // N.B. MSVC complains if we use `1U` here, since AliasAttr' ctor takes
+  // an unsigned long long.
+  return AliasAttr(1ULL << (ArgNum + AttrFirstArgIndex));
+}
+
+AliasAttrs getGlobalOrArgAttrFromValue(const Value &Val) {
+  if (isa<GlobalValue>(Val))
+    return AttrGlobal;
+
+  if (auto *Arg = dyn_cast<Argument>(&Val))
+    // Only pointer arguments should have the argument attribute,
+    // because things can't escape through scalars without us seeing a
+    // cast, and thus, interaction with them doesn't matter.
+    if (!Arg->hasNoAliasAttr() && Arg->getType()->isPointerTy())
+      return argNumberToAttr(Arg->getArgNo());
+  return AttrNone;
+}
+
+bool isGlobalOrArgAttr(AliasAttrs Attr) {
+  return Attr.reset(AttrEscapedIndex)
+      .reset(AttrUnknownIndex)
+      .reset(AttrCallerIndex)
+      .any();
+}
+
+AliasAttrs getExternallyVisibleAttrs(AliasAttrs Attr) {
+  return Attr & AliasAttrs(ExternalAttrMask);
+}
+
+Optional<InstantiatedValue> instantiateInterfaceValue(InterfaceValue IValue,
+                                                      CallBase &Call) {
+  auto Index = IValue.Index;
+  auto *V = (Index == 0) ? &Call : Call.getArgOperand(Index - 1);
+  if (V->getType()->isPointerTy())
+    return InstantiatedValue{V, IValue.DerefLevel};
+  return None;
+}
+
+Optional<InstantiatedRelation>
+instantiateExternalRelation(ExternalRelation ERelation, CallBase &Call) {
+  auto From = instantiateInterfaceValue(ERelation.From, Call);
+  if (!From)
+    return None;
+  auto To = instantiateInterfaceValue(ERelation.To, Call);
+  if (!To)
+    return None;
+  return InstantiatedRelation{*From, *To, ERelation.Offset};
+}
+
+Optional<InstantiatedAttr> instantiateExternalAttribute(ExternalAttribute EAttr,
+                                                        CallBase &Call) {
+  auto Value = instantiateInterfaceValue(EAttr.IValue, Call);
+  if (!Value)
+    return None;
+  return InstantiatedAttr{*Value, EAttr.Attr};
+}
+}
+}