[coro] Use swift mangling for resume functions

[aschwaighofer]

Summary

The resume partial functions generated for swift suspend points will now
use a Swift mangling suffix.

Await resume partial functions will use the suffix 'TQ'[0-9]+'_' (e.g "...TQ0_")
and suspend resume partial functions will use the suffix 'TY'[0-9]+'_'
(e.g "...TY1_").

[nate_chandler]

lgtm

llvm/lib/Transforms/Coroutines/CoroSplit.cpp

static void splitAsyncCoroutine(Function &F, coro::Shape &Shape,
   auto NextF = std::next(F.getIterator());
 
   // Create a continuation function for each of the suspend points.
   Clones.reserve(Shape.CoroSuspends.size());
   for (size_t Idx = 0, End = Shape.CoroSuspends.size(); Idx != End; ++Idx) {
     auto *Suspend = cast<CoroSuspendAsyncInst>(Shape.CoroSuspends[Idx]);
 
     // Create the clone declaration.
+    auto resumeNameSuffix = ".resume.";
+    auto projectionFunctionName =
+        Suspend->getAsyncContextProjectionFunction()->getName();
+    bool useSwiftMangling = false;
+    if (projectionFunctionName.equals("__swift_async_resume_project_context")) {
+      resumeNameSuffix = "TQ";
+      useSwiftMangling = true;
+    } else if (projectionFunctionName.equals(
+                   "__swift_async_resume_get_context")) {
+      resumeNameSuffix = "TY";
+      useSwiftMangling = true;
+    }
     auto *Continuation = createCloneDeclaration(
-        F, Shape, ".resume." + Twine(Idx), NextF, Suspend);
+        F, Shape,
+        useSwiftMangling ? resumeNameSuffix + Twine(Idx) + "_"
+                         : resumeNameSuffix + Twine(Idx),
+        NextF, Suspend);
     Clones.push_back(Continuation);
 
     // Insert a branch to a new return block immediately before the suspend
     // point.
     auto *SuspendBB = Suspend->getParent();
     auto *NewSuspendBB = SuspendBB->splitBasicBlock(Suspend);
     auto *Branch = cast<BranchInst>(SuspendBB->getTerminator());
 

llvm/test/Transforms/Coroutines/coro-async.ll

define swiftcc void @my_async_function.my_other_async_function_fp.apply(i8* %fnPtr, i8* %async.ctxt, %async.task* %task, %async.actor* %actor) {
   %callee = bitcast i8* %fnPtr to void(i8*, %async.task*, %async.actor*)*
   tail call swiftcc void %callee(i8* %async.ctxt, %async.task* %task, %async.actor* %actor)
   ret void
 }
 
 declare void @some_user(i64)
 declare void @some_may_write(i64*)
 
+define i8* @__swift_async_resume_project_context(i8* %ctxt) {
+entry:
+  %resume_ctxt_addr = bitcast i8* %ctxt to i8**
+  %resume_ctxt = load i8*, i8** %resume_ctxt_addr, align 8
+  ret i8* %resume_ctxt
+}
+
 define i8* @resume_context_projection(i8* %ctxt) {
 entry:
   %resume_ctxt_addr = bitcast i8* %ctxt to i8**
   %resume_ctxt = load i8*, i8** %resume_ctxt_addr, align 8
   ret i8* %resume_ctxt
 }
 
 
entry:
   %callee_context.return_to_caller.addr = getelementptr inbounds %async.ctxt, %async.ctxt* %callee_context.0, i32 0, i32 1
   %return_to_caller.addr = bitcast void(i8*, %async.task*, %async.actor*)** %callee_context.return_to_caller.addr to i8**
   %resume.func_ptr = call i8* @llvm.coro.async.resume()
   store i8* %resume.func_ptr, i8** %return_to_caller.addr
 
   ; store caller context into callee context
   %callee_context.caller_context.addr = getelementptr inbounds %async.ctxt, %async.ctxt* %callee_context.0, i32 0, i32 0
   store i8* %async.ctxt, i8** %callee_context.caller_context.addr
-  %resume_proj_fun = bitcast i8*(i8*)* @resume_context_projection to i8*
+  %resume_proj_fun = bitcast i8*(i8*)* @__swift_async_resume_project_context to i8*
   %callee = bitcast void(i8*, %async.task*, %async.actor*)* @asyncSuspend to i8*
   %res = call {i8*, i8*, i8*} (i32, i8*, i8*, ...) @llvm.coro.suspend.async(i32 0,
                                                   i8* %resume.func_ptr,
                                                   i8* %resume_proj_fun,
                                                   void (i8*, i8*, %async.task*, %async.actor*)* @my_async_function.my_other_async_function_fp.apply,
                                                   i8* %callee, i8* %callee_context, %async.task* %task, %async.actor *%actor), !dbg !5
 
   call void @llvm.coro.async.context.dealloc(i8* %callee_context)

 ; CHECK:   tail call void @some_may_write(i64* nonnull %proj.1)
 ; CHECK:   [[TASK:%.*]] = bitcast %async.task* %task to i8*
 ; CHECK:   [[CALLEE_CTXT:%.*]] = tail call i8* @llvm.coro.async.context.alloc(i8* [[TASK]], i8* bitcast (<{ i32, i32 }>* @my_other_async_function_fp to i8*))
 ; CHECK:   [[CALLEE_CTXT_SPILL:%.*]] = getelementptr inbounds i8, i8* %async.ctxt, i64 160
 ; CHECK:   [[CAST2:%.*]] = bitcast i8* [[CALLEE_CTXT_SPILL]] to i8**
 ; CHECK:   store i8* [[CALLEE_CTXT]], i8** [[CAST2]]
 ; CHECK:   [[TYPED_RETURN_TO_CALLER_ADDR:%.*]] = getelementptr inbounds i8, i8* [[CALLEE_CTXT]], i64 8
 ; CHECK:   [[RETURN_TO_CALLER_ADDR:%.*]] = bitcast i8* [[TYPED_RETURN_TO_CALLER_ADDR]] to i8**
-; CHECK:   store i8* bitcast (void (i8*, i8*, i8*)* @my_async_function.resume.0 to i8*), i8** [[RETURN_TO_CALLER_ADDR]]
+; CHECK:   store i8* bitcast (void (i8*, i8*, i8*)* @my_async_functionTQ0_ to i8*), i8** [[RETURN_TO_CALLER_ADDR]]
 ; CHECK:   [[CALLER_CONTEXT_ADDR:%.*]] = bitcast i8* [[CALLEE_CTXT]] to i8**
 ; CHECK:   store i8* %async.ctxt, i8** [[CALLER_CONTEXT_ADDR]]
 ; CHECK:   tail call swiftcc void @asyncSuspend(i8* [[CALLEE_CTXT]], %async.task* %task, %async.actor* %actor)
 ; CHECK:   ret void
 ; CHECK: }
 
-; CHECK-LABEL: define internal swiftcc void @my_async_function.resume.0(i8* nocapture readonly swiftasync %0, i8* %1, i8* nocapture readnone %2)
+; CHECK-LABEL: define internal swiftcc void @my_async_functionTQ0_(i8* nocapture readonly swiftasync %0, i8* %1, i8* nocapture readnone %2)
 ; CHECK-SAME: !dbg ![[SP2:[0-9]+]] {
 ; CHECK: entryresume.0:
 ; CHECK:   [[CALLER_CONTEXT_ADDR:%.*]] = bitcast i8* %0 to i8**
 ; CHECK:   [[CALLER_CONTEXT:%.*]] = load i8*, i8** [[CALLER_CONTEXT_ADDR]]
 ; CHECK:   [[FRAME_PTR:%.*]] = getelementptr inbounds i8, i8* [[CALLER_CONTEXT]], i64 128
 ; CHECK:   [[CALLEE_CTXT_SPILL_ADDR:%.*]] = getelementptr inbounds i8, i8* [[CALLER_CONTEXT]], i64 160
 ; CHECK:   [[CAST1:%.*]] = bitcast i8* [[CALLEE_CTXT_SPILL_ADDR]] to i8**
 ; CHECK:   [[CALLEE_CTXT_RELOAD:%.*]] = load i8*, i8** [[CAST1]]

 define swiftcc void @top_level_caller(i8* %ctxt, i8* %task, i8* %actor) {
   %prepare = call i8* @llvm.coro.prepare.async(i8* bitcast (void (i8*, %async.task*,  %async.actor*)* @my_async_function to i8*))
   %f = bitcast i8* %prepare to void (i8*, i8*, i8*)*
   call swiftcc void %f(i8* %ctxt, i8* %task, i8* %actor)
   ret void
 }
 
 ; CHECK-LABEL: define swiftcc void @top_level_caller(i8* %ctxt, i8* %task, i8* %actor)
-; CHECK: store i8* bitcast (void (i8*, i8*, i8*)* @my_async_function.resume.0
+; CHECK: store i8* bitcast (void (i8*, i8*, i8*)* @my_async_functionTQ0_
 ; CHECK: store i8* %ctxt
 ; CHECK: tail call swiftcc void @asyncSuspend
 ; CHECK: ret void
 
 @dont_crash_on_cf_fp = constant <{ i32, i32 }>
   <{ i32 trunc ( ; Relative pointer to async function
        i64 sub (
          i64 ptrtoint (void (i8*, %async.task*, %async.actor*)* @my_async_function to i64),

 ; CHECK: ![[SP1]] = distinct !DISubprogram(name: "my_async_function",
 ; CHECK-SAME:                              linkageName: "my_async_function",
 ; CHECK-SAME:                              scopeLine: 1
 !1 = distinct !DISubprogram(name: "my_async_function",
                             linkageName: "my_async_function",
                             scope: !2, file: !3, line: 1, type: !4,
                             scopeLine: 1, spFlags: DISPFlagDefinition, unit: !2)
 ; CHECK: ![[SP2]] = distinct !DISubprogram(name: "my_async_function",
-; CHECK-SAME:                              linkageName: "my_async_function.resume.0",
+; CHECK-SAME:                              linkageName: "my_async_functionTQ0_",
 ; CHECK-SAME:                              scopeLine: 2
 !2 = distinct !DICompileUnit(language: DW_LANG_Swift, file: !3, emissionKind: FullDebug)
 !3 = !DIFile(filename: "/tmp/1.swift", directory: "/")
 !4 = !DISubroutineType(types: !{})
 !5 = !DILocation(line: 2, column: 0, scope: !1)
 
 ; CHECK: ![[SP3]] = distinct !DISubprogram(name: "my_async_function2",
 ; CHECK-SAME:                              linkageName: "my_async_function2",