From ecc4595ce4cb7fb6fdf6182693b6beef2f1cb5c6 Mon Sep 17 00:00:00 2001
From: Reid Kleckner <reid@kleckner.net>
Date: Tue, 14 Apr 2015 20:38:14 +0000
Subject: [PATCH] [Inliner] Don't inline functions with frameescape calls

Inlining such intrinsics is very difficult, since you need to
simultaneously transform many calls to llvm.framerecover and potentially
duplicate the functions containing them.  Normally this intrinsic isn't
added until EH preparation, which is part of the backend pass pipeline
after inlining.  However, if it were to get fed through the inliner,
this change will ensure that it doesn't break the code.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234937 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Analysis/IPA/InlineCost.cpp       | 27 +++++++++++-----
 test/Transforms/Inline/frameescape.ll | 44 +++++++++++++++++++++++++++
 2 files changed, 63 insertions(+), 8 deletions(-)
 create mode 100644 test/Transforms/Inline/frameescape.ll

diff --git a/lib/Analysis/IPA/InlineCost.cpp b/lib/Analysis/IPA/InlineCost.cpp
index aa015647926..cacf70d041b 100644
--- a/lib/Analysis/IPA/InlineCost.cpp
+++ b/lib/Analysis/IPA/InlineCost.cpp
@@ -64,6 +64,7 @@ class CallAnalyzer : public InstVisitor<CallAnalyzer, bool> {
   bool ContainsNoDuplicateCall;
   bool HasReturn;
   bool HasIndirectBr;
+  bool HasFrameEscape;
 
   /// Number of bytes allocated statically by the callee.
   uint64_t AllocatedSize;
@@ -148,12 +149,12 @@ public:
         IsCallerRecursive(false), IsRecursiveCall(false),
         ExposesReturnsTwice(false), HasDynamicAlloca(false),
         ContainsNoDuplicateCall(false), HasReturn(false), HasIndirectBr(false),
-        AllocatedSize(0), NumInstructions(0), NumVectorInstructions(0),
-        FiftyPercentVectorBonus(0), TenPercentVectorBonus(0), VectorBonus(0),
-        NumConstantArgs(0), NumConstantOffsetPtrArgs(0), NumAllocaArgs(0),
-        NumConstantPtrCmps(0), NumConstantPtrDiffs(0),
-        NumInstructionsSimplified(0), SROACostSavings(0),
-        SROACostSavingsLost(0) {}
+        HasFrameEscape(false), AllocatedSize(0), NumInstructions(0),
+        NumVectorInstructions(0), FiftyPercentVectorBonus(0),
+        TenPercentVectorBonus(0), VectorBonus(0), NumConstantArgs(0),
+        NumConstantOffsetPtrArgs(0), NumAllocaArgs(0), NumConstantPtrCmps(0),
+        NumConstantPtrDiffs(0), NumInstructionsSimplified(0),
+        SROACostSavings(0), SROACostSavingsLost(0) {}
 
   bool analyzeCall(CallSite CS);
 
@@ -743,6 +744,9 @@ bool CallAnalyzer::visitCallSite(CallSite CS) {
       case Intrinsic::memmove:
         // SROA can usually chew through these intrinsics, but they aren't free.
         return false;
+      case Intrinsic::frameescape:
+        HasFrameEscape = true;
+        return false;
       }
     }
 
@@ -941,7 +945,7 @@ bool CallAnalyzer::analyzeBlock(BasicBlock *BB,
 
     // If the visit this instruction detected an uninlinable pattern, abort.
     if (IsRecursiveCall || ExposesReturnsTwice || HasDynamicAlloca ||
-        HasIndirectBr)
+        HasIndirectBr || HasFrameEscape)
       return false;
 
     // If the caller is a recursive function then we don't want to inline
@@ -1171,7 +1175,7 @@ bool CallAnalyzer::analyzeCall(CallSite CS) {
     // returns false, and we can bail on out.
     if (!analyzeBlock(BB, EphValues)) {
       if (IsRecursiveCall || ExposesReturnsTwice || HasDynamicAlloca ||
-          HasIndirectBr)
+          HasIndirectBr || HasFrameEscape)
         return false;
 
       // If the caller is a recursive function then we don't want to inline
@@ -1372,6 +1376,13 @@ bool InlineCostAnalysis::isInlineViable(Function &F) {
       if (!ReturnsTwice && CS.isCall() &&
           cast<CallInst>(CS.getInstruction())->canReturnTwice())
         return false;
+
+      // Disallow inlining functions that call @llvm.frameescape. Doing this
+      // correctly would require major changes to the inliner.
+      if (CS.getCalledFunction() &&
+          CS.getCalledFunction()->getIntrinsicID() ==
+              llvm::Intrinsic::frameescape)
+        return false;
     }
   }
 
diff --git a/test/Transforms/Inline/frameescape.ll b/test/Transforms/Inline/frameescape.ll
new file mode 100644
index 00000000000..be185dc7467
--- /dev/null
+++ b/test/Transforms/Inline/frameescape.ll
@@ -0,0 +1,44 @@
+; RUN: opt -inline -S < %s | FileCheck %s
+
+; PR23216: We can't inline functions using llvm.frameescape.
+
+declare void @llvm.frameescape(...)
+declare i8* @llvm.frameaddress(i32)
+declare i8* @llvm.framerecover(i8*, i8*, i32)
+
+define internal void @foo(i8* %fp) {
+  %a.i8 = call i8* @llvm.framerecover(i8* bitcast (i32 ()* @bar to i8*), i8* %fp, i32 0)
+  %a = bitcast i8* %a.i8 to i32*
+  store i32 42, i32* %a
+  ret void
+}
+
+define internal i32 @bar() {
+entry:
+  %a = alloca i32
+  call void (...)* @llvm.frameescape(i32* %a)
+  %fp = call i8* @llvm.frameaddress(i32 0)
+  tail call void @foo(i8* %fp)
+  %r = load i32, i32* %a
+  ret i32 %r
+}
+
+; We even bail when someone marks it alwaysinline.
+define internal i32 @bar_alwaysinline() alwaysinline {
+entry:
+  %a = alloca i32
+  call void (...)* @llvm.frameescape(i32* %a)
+  tail call void @foo(i8* null)
+  ret i32 0
+}
+
+define i32 @bazz() {
+entry:
+  %r = tail call i32 @bar()
+  %r1 = tail call i32 @bar_alwaysinline()
+  ret i32 %r
+}
+
+; CHECK: define i32 @bazz()
+; CHECK: call i32 @bar()
+; CHECK: call i32 @bar_alwaysinline()
-- 
2.34.1