[do not merge] Support for hot/cold splitting in swift

lib/Transforms/Utils/CodeExtractor.cpp

@@ -895,11 +895,19 @@ emitCallAndSwitchStatement(Function *newFunction, BasicBlock *codeReplacer,
   const DataLayout &DL = M->getDataLayout();
 
   // Add inputs as params, or to be filled into the struct
-  for (Value *input : inputs)
+  unsigned ArgNo = 0;
+  SmallVector<unsigned, 1> SwiftErrorArgs;
+  for (Value *input : inputs) {
     if (AggregateArgs)
       StructValues.push_back(input);
-    else
+    else {
       params.push_back(input);
+      if (auto *Alloca = dyn_cast<AllocaInst>(input))
+        if (Alloca->isSwiftError())
+          SwiftErrorArgs.push_back(ArgNo);
+    }
+    ++ArgNo;
+  }
 
   // Create allocas for the outputs
   for (Value *output : outputs) {
@@ -955,6 +963,12 @@ emitCallAndSwitchStatement(Function *newFunction, BasicBlock *codeReplacer,
   }
   codeReplacer->getInstList().push_back(call);
 
+  // Set swifterror parameter attributes.
+  for (unsigned SwiftErrArgNo : SwiftErrorArgs) {
+    call->addParamAttr(SwiftErrArgNo, Attribute::SwiftError);
+    newFunction->addParamAttr(SwiftErrArgNo, Attribute::SwiftError);
+  }
+
   Function::arg_iterator OutputArgBegin = newFunction->arg_begin();
   unsigned FirstOut = inputs.size();
   if (!AggregateArgs)
@@ -1370,7 +1384,8 @@ Function *CodeExtractor::extractCodeRegion() {
 
   // Mark the new function `noreturn` if applicable.
   bool doesNotReturn = none_of(*newFunction, [](const BasicBlock &BB) {
-    return isa<ReturnInst>(BB.getTerminator());
+  	auto *Term = BB.getTerminator();
+    return isa<ReturnInst>(Term) || isa<CatchReturnInst>(Term) || isa<ResumeInst>(Term);
   });
   if (doesNotReturn)
     newFunction->setDoesNotReturn();

test/Transforms/HotColdSplit/eh-pads.ll

@@ -0,0 +1,65 @@
+; RUN: opt -S -hotcoldsplit < %s | FileCheck %s
+
+target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-apple-macosx10.14.0"
+
+; CHECK-LABEL: define {{.*}}@foo(
+; CHECK: landingpad
+; CHECK: sideeffect(i32 2)
+define void @foo(i32 %cond) personality i8 0 {
+entry:
+  invoke void @llvm.donothing() to label %normal unwind label %exception
+
+exception:
+  ; Note: EH pads are not candidates for region entry points.
+  %cleanup = landingpad i8 cleanup
+  br label %continue_exception
+
+continue_exception:
+  call void @sideeffect(i32 0)
+  call void @sideeffect(i32 1)
+  call void @sink()
+  ret void
+
+normal:
+  call void @sideeffect(i32 2)
+  ret void
+}
+
+; CHECK-LABEL: define {{.*}}@bar(
+; CHECK-NOT: landingpad
+define void @bar(i32 %cond) personality i8 0 {
+entry:
+  br i1 undef, label %exit, label %continue
+
+exit:
+  ret void
+
+continue:
+  invoke void @sink() to label %normal unwind label %exception
+
+exception:
+  ; Note: EH pads are not candidates for region entry points.
+  %cleanup = landingpad i8 cleanup
+  ret void
+
+normal:
+  call void @sideeffect(i32 0)
+  call void @sideeffect(i32 1)
+  ret void
+}
+
+; CHECK-LABEL: define {{.*}}@foo.cold.1(
+; CHECK: sideeffect(i32 0)
+; CHECK: sideeffect(i32 1)
+; CHECK: sink
+
+; CHECK-LABEL: define {{.*}}@bar.cold.1(
+; CHECK: sideeffect(i32 0)
+; CHECK: sideeffect(i32 1)
+
+declare void @sideeffect(i32)
+
+declare void @sink() cold
+
+declare void @llvm.donothing() nounwind readnone

test/Transforms/HotColdSplit/extraction-subregion-breaks-phis.ll

@@ -0,0 +1,63 @@
+; RUN: opt -S -hotcoldsplit < %s | FileCheck %s
+
+target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-apple-macosx10.14.0"
+
+; CHECK-LABEL: define {{.*}}@foo(
+; CHECK: call {{.*}}@foo.cold.1(
+; CHECK: unreachable
+
+; CHECK-LABEL: define {{.*}}@foo.cold.1(
+; CHECK: switch i32 undef, label %sw.epilog.i
+define void @foo(i32 %QMM) {
+entry:
+  switch i32 %QMM, label %entry.if.end16_crit_edge [
+    i32 1, label %if.then
+  ]
+
+entry.if.end16_crit_edge:                         ; preds = %entry
+  br label %if.end16
+
+if.then:                                          ; preds = %entry
+  br i1 undef, label %cond.true.i.i, label %_ZN10StringView8popFrontEv.exit.i
+
+cond.true.i.i:                                    ; preds = %if.then
+  ret void
+
+_ZN10StringView8popFrontEv.exit.i:                ; preds = %if.then
+  switch i32 undef, label %sw.epilog.i [
+    i32 81, label %if.end16
+    i32 82, label %sw.bb4.i
+    i32 83, label %sw.bb8.i
+    i32 84, label %sw.bb12.i
+    i32 65, label %if.end16
+    i32 66, label %sw.bb20.i
+    i32 67, label %sw.bb24.i
+    i32 68, label %sw.bb28.i
+  ]
+
+sw.bb4.i:                                         ; preds = %_ZN10StringView8popFrontEv.exit.i
+  br label %if.end16
+
+sw.bb8.i:                                         ; preds = %_ZN10StringView8popFrontEv.exit.i
+  br label %if.end16
+
+sw.bb12.i:                                        ; preds = %_ZN10StringView8popFrontEv.exit.i
+  br label %if.end16
+
+sw.bb20.i:                                        ; preds = %_ZN10StringView8popFrontEv.exit.i
+  br label %if.end16
+
+sw.bb24.i:                                        ; preds = %_ZN10StringView8popFrontEv.exit.i
+  br label %if.end16
+
+sw.bb28.i:                                        ; preds = %_ZN10StringView8popFrontEv.exit.i
+  br label %if.end16
+
+sw.epilog.i:                                      ; preds = %_ZN10StringView8popFrontEv.exit.i
+  br label %if.end16
+
+if.end16:                                         ; preds = %sw.epilog.i, %sw.bb28.i, %sw.bb24.i, %sw.bb20.i, %sw.bb12.i, %sw.bb8.i, %sw.bb4.i, %_ZN10StringView8popFrontEv.exit.i, %_ZN10StringView8popFrontEv.exit.i, %entry.if.end16_crit_edge
+  %0 = phi i8 [ 0, %entry.if.end16_crit_edge ], [ 0, %_ZN10StringView8popFrontEv.exit.i ], [ 0, %_ZN10StringView8popFrontEv.exit.i ], [ 1, %sw.bb4.i ], [ 2, %sw.bb8.i ], [ 3, %sw.bb12.i ], [ 1, %sw.bb20.i ], [ 2, %sw.bb24.i ], [ 3, %sw.bb28.i ], [ 0, %sw.epilog.i ]
+  unreachable
+}

test/Transforms/HotColdSplit/forward-dfs-reaches-marked-block.ll

@@ -0,0 +1,29 @@
+; RUN: opt -hotcoldsplit -S < %s | FileCheck %s
+
+target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-apple-macosx10.14.0"
+
+; CHECK-LABEL: define {{.*}}@fun
+; CHECK: call {{.*}}@fun.cold.1(
+define void @fun() {
+entry:
+  br i1 undef, label %if.then, label %if.else
+
+if.then:
+  ; This will be marked by the inverse DFS on sink-predecesors.
+  br label %sink
+
+sink:
+  call void @sink()
+
+  ; Do not allow the forward-DFS on sink-successors to mark the block again.
+  br i1 undef, label %if.then, label %if.then.exit
+
+if.then.exit:
+  ret void
+
+if.else:
+  ret void
+}
+
+declare void @sink() cold

test/Transforms/HotColdSplit/mark-the-whole-func-cold.ll

@@ -0,0 +1,64 @@
+; RUN: opt -S -hotcoldsplit < %s | FileCheck %s
+
+; Source:
+; 
+; extern __attribute__((cold)) void sink();
+; extern void sideeffect(int);
+; void foo(int cond1, int cond2) {
+;     if (cond1) {
+;         if (cond2) {
+;             sideeffect(0);
+;         } else {
+;             sideeffect(1);
+;         }
+;         sink();
+;     } else {
+;         sideeffect(2);
+;     }
+;     sink();
+; }
+
+target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-apple-macosx10.14.0"
+
+; CHECK: define {{.*}}@_Z3fooii{{.*}}#[[outlined_func_attr:[0-9]+]]
+; CHECK-NOT: _Z3fooii.cold
+; CHECK: attributes #[[outlined_func_attr]] = { {{.*}}minsize
+define void @_Z3fooii(i32, i32) {
+  %3 = alloca i32, align 4
+  %4 = alloca i32, align 4
+  store i32 %0, i32* %3, align 4
+  store i32 %1, i32* %4, align 4
+  %5 = load i32, i32* %3, align 4
+  %6 = icmp ne i32 %5, 0
+  br i1 %6, label %7, label %13
+
+; <label>:7:                                      ; preds = %2
+  %8 = load i32, i32* %4, align 4
+  %9 = icmp ne i32 %8, 0
+  br i1 %9, label %10, label %11
+
+; <label>:10:                                     ; preds = %7
+  call void @_Z10sideeffecti(i32 0)
+  br label %12
+
+; <label>:11:                                     ; preds = %7
+  call void @_Z10sideeffecti(i32 1)
+  br label %12
+
+; <label>:12:                                     ; preds = %11, %10
+  call void @_Z4sinkv() #3
+  br label %14
+
+; <label>:13:                                     ; preds = %2
+  call void @_Z10sideeffecti(i32 2)
+  br label %14
+
+; <label>:14:                                     ; preds = %13, %12
+  call void @_Z4sinkv() #3
+  ret void
+}
+
+declare void @_Z10sideeffecti(i32)
+
+declare void @_Z4sinkv() cold

test/Transforms/HotColdSplit/noreturn.ll

@@ -0,0 +1,73 @@
+; RUN: opt -hotcoldsplit -S < %s | FileCheck %s
+
+target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-apple-macosx10.14.0"
+
+%struct.__jmp_buf_tag = type { [8 x i64], i32, %struct.__sigset_t }
+%struct.__sigset_t = type { [16 x i64] }
+
+; Don't outline noreturn calls which aren't explicitly marked cold.
+
+; CHECK-LABEL: define {{.*}}@foo(
+; CHECK-NOT: foo.cold.1
+define void @foo(i32, %struct.__jmp_buf_tag*) {
+  %3 = icmp eq i32 %0, 0
+  tail call void @_Z10sideeffectv()
+  br i1 %3, label %5, label %4
+
+; <label>:4:                                      ; preds = %2
+  tail call void @longjmp(%struct.__jmp_buf_tag* %1, i32 0)
+  unreachable
+
+; <label>:5:                                      ; preds = %2
+  ret void
+}
+
+; Do outline noreturn calls marked cold.
+
+; CHECK-LABEL: define {{.*}}@bar(
+; CHECK: call {{.*}}@bar.cold.1(
+define void @bar(i32) {
+  %2 = icmp eq i32 %0, 0
+  tail call void @_Z10sideeffectv()
+  br i1 %2, label %sink, label %exit
+
+sink:
+  tail call void @_Z10sideeffectv()
+  tail call void @_Z10sideeffectv()
+  tail call void @_Z10sideeffectv()
+  call void @llvm.trap()
+  unreachable
+
+exit:
+  ret void
+}
+
+; Do outline noreturn calls preceded by a cold call.
+
+; CHECK-LABEL: define {{.*}}@baz(
+; CHECK: call {{.*}}@baz.cold.1(
+define void @baz(i32, %struct.__jmp_buf_tag*) {
+  %3 = icmp eq i32 %0, 0
+  tail call void @_Z10sideeffectv()
+  br i1 %3, label %5, label %4
+
+; <label>:4:                                      ; preds = %2
+  call void @sink()
+  tail call void @longjmp(%struct.__jmp_buf_tag* %1, i32 0)
+  unreachable
+
+; <label>:5:                                      ; preds = %2
+  ret void
+}
+
+; CHECK-LABEL: define {{.*}}@bar.cold.1(
+; CHECK: call {{.*}}@llvm.trap(
+
+declare void @sink() cold
+
+declare void @llvm.trap() noreturn cold
+
+declare void @_Z10sideeffectv()
+
+declare void @longjmp(%struct.__jmp_buf_tag*, i32) noreturn nounwind

test/Transforms/HotColdSplit/outline-cold-asm.ll

@@ -0,0 +1,27 @@
+; RUN: opt -hotcoldsplit -S < %s | FileCheck %s
+
+target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-apple-macosx10.14.0"
+
+; CHECK-LABEL: define {{.*}}@fun(
+; CHECK: call {{.*}}@fun.cold.1(
+
+; CHECK-LABEL: define {{.*}}@fun.cold.1(
+; CHECK: asm ""
+
+define void @fun() {
+entry:
+  br i1 undef, label %if.then, label %if.else
+
+if.then:
+  ret void
+
+if.else:
+  call void asm "", ""()
+  call void @sink()
+  call void @sink()
+  call void @sink()
+  ret void
+}
+
+declare void @sink() cold