[llvm] 29e2d94 - Option to ignore assume like intrinsic uses in hasAddressTaken()

[Stanislav Mekhanoshin via llvm-commits]

Author: Stanislav Mekhanoshin
Date: 2021-02-25T09:48:29-08:00
New Revision: 29e2d9461a91b76665139002a5b323fbb1b19d82

URL: https://github.com/llvm/llvm-project/commit/29e2d9461a91b76665139002a5b323fbb1b19d82
DIFF: https://github.com/llvm/llvm-project/commit/29e2d9461a91b76665139002a5b323fbb1b19d82.diff

LOG: Option to ignore assume like intrinsic uses in hasAddressTaken()

Differential Revision: https://reviews.llvm.org/D96081

Added: 
    llvm/test/Analysis/CallGraph/ignore-assumelike-calls.ll

Modified: 
    llvm/include/llvm/IR/Function.h
    llvm/lib/Analysis/CallGraph.cpp
    llvm/lib/IR/Function.cpp

Removed: 
    


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diff  --git a/llvm/include/llvm/IR/Function.h b/llvm/include/llvm/IR/Function.h
index 7e209bb3769b..187da2a09027 100644
--- a/llvm/include/llvm/IR/Function.h
+++ b/llvm/include/llvm/IR/Function.h
@@ -872,11 +872,12 @@ class Function : public GlobalObject, public ilist_node<Function> {
 
   /// hasAddressTaken - returns true if there are any uses of this function
   /// other than direct calls or invokes to it, or blockaddress expressions.
-  /// Optionally passes back an offending user for diagnostic purposes and
-  /// ignores callback uses.
+  /// Optionally passes back an offending user for diagnostic purposes,
+  /// ignores callback uses, and assume like pointer annotation calls.
   ///
   bool hasAddressTaken(const User ** = nullptr,
-                       bool IgnoreCallbackUses = false) const;
+                       bool IgnoreCallbackUses = false,
+                       bool IgnoreAssumeLikeCalls = false) const;
 
   /// isDefTriviallyDead - Return true if it is trivially safe to remove
   /// this function definition from the module (because it isn't externally

diff  --git a/llvm/lib/Analysis/CallGraph.cpp b/llvm/lib/Analysis/CallGraph.cpp
index 9b212e564a46..014f3eb4abc9 100644
--- a/llvm/lib/Analysis/CallGraph.cpp
+++ b/llvm/lib/Analysis/CallGraph.cpp
@@ -80,7 +80,8 @@ void CallGraph::addToCallGraph(Function *F) {
   // If this function has external linkage or has its address taken and
   // it is not a callback, then anything could call it.
   if (!F->hasLocalLinkage() ||
-      F->hasAddressTaken(nullptr, /*IgnoreCallbackUses=*/true))
+      F->hasAddressTaken(nullptr, /*IgnoreCallbackUses=*/true,
+                         /* IgnoreAssumeLikeCalls */ true))
     ExternalCallingNode->addCalledFunction(nullptr, Node);
 
   populateCallGraphNode(Node);

diff  --git a/llvm/lib/IR/Function.cpp b/llvm/lib/IR/Function.cpp
index 17247123f87f..c6932f0ec446 100644
--- a/llvm/lib/IR/Function.cpp
+++ b/llvm/lib/IR/Function.cpp
@@ -31,6 +31,7 @@
 #include "llvm/IR/InstIterator.h"
 #include "llvm/IR/Instruction.h"
 #include "llvm/IR/Instructions.h"
+#include "llvm/IR/IntrinsicInst.h"
 #include "llvm/IR/Intrinsics.h"
 #include "llvm/IR/IntrinsicsAArch64.h"
 #include "llvm/IR/IntrinsicsAMDGPU.h"
@@ -1578,9 +1579,10 @@ Optional<Function *> Intrinsic::remangleIntrinsicFunction(Function *F) {
 
 /// hasAddressTaken - returns true if there are any uses of this function
 /// other than direct calls or invokes to it. Optionally ignores callback
-/// uses.
+/// uses and assume like pointer annotation calls.
 bool Function::hasAddressTaken(const User **PutOffender,
-                               bool IgnoreCallbackUses) const {
+                               bool IgnoreCallbackUses,
+                               bool IgnoreAssumeLikeCalls) const {
   for (const Use &U : uses()) {
     const User *FU = U.getUser();
     if (isa<BlockAddress>(FU))
@@ -1594,6 +1596,17 @@ bool Function::hasAddressTaken(const User **PutOffender,
 
     const auto *Call = dyn_cast<CallBase>(FU);
     if (!Call) {
+      if (IgnoreAssumeLikeCalls) {
+        if (const auto *FI = dyn_cast<Instruction>(FU)) {
+          if (FI->isCast() && !FI->user_empty() &&
+              llvm::all_of(FU->users(), [](const User *U) {
+                if (const auto *I = dyn_cast<IntrinsicInst>(U))
+                  return I->isAssumeLikeIntrinsic();
+                return false;
+              }))
+            continue;
+        }
+      }
       if (PutOffender)
         *PutOffender = FU;
       return true;

diff  --git a/llvm/test/Analysis/CallGraph/ignore-assumelike-calls.ll b/llvm/test/Analysis/CallGraph/ignore-assumelike-calls.ll
new file mode 100644
index 000000000000..4bacec43782f
--- /dev/null
+++ b/llvm/test/Analysis/CallGraph/ignore-assumelike-calls.ll
@@ -0,0 +1,26 @@
+; RUN: opt < %s -print-callgraph -disable-output 2>&1 | FileCheck %s
+; CHECK: Call graph node <<null function>><<{{.*}}>>  #uses=0
+; CHECK-NEXT:   CS<None> calls function 'cast_only'
+; CHECK-NEXT:   CS<None> calls function 'llvm.lifetime.start.p0i8'
+; CHECK-EMPTY:
+; CHECK-NEXT:   Call graph node for function: 'cast_only'<<{{.*}}>>  #uses=1
+; CHECK-EMPTY:
+; CHECK-NEXT:   Call graph node for function: 'llvm.lifetime.start.p0i8'<<{{.*}}>>  #uses=1
+; CHECK-EMPTY:
+; CHECK-NEXT:   Call graph node for function: 'used_by_lifetime'<<{{.*}}>>  #uses=0
+; CHECK-EMPTY:
+
+define internal void @used_by_lifetime() {
+entry:
+  %c = bitcast void()* @used_by_lifetime to i8*
+  call void @llvm.lifetime.start.p0i8(i64 4, i8* %c)
+  ret void
+}
+
+define internal void @cast_only() {
+entry:
+  %c = bitcast void()* @cast_only to i8*
+  ret void
+}
+
+declare void @llvm.lifetime.start.p0i8(i64, i8* nocapture)