[AArch64] Fix mismatch in prologue and epilogue for funclets on Windows

The generated code for a funclet can have an add to sp in the epilogue
for which there is no corresponding sub in the prologue.

This patch removes the early return from emitPrologue that was
preventing the sub to sp, and instead conditionalizes the appropriate
parts of the rest of the function.

Fixes https://bugs.llvm.org/show_bug.cgi?id=45345

Differential Revision: https://reviews.llvm.org/D77015

(cherry picked from commit 522b4c4b88a5606b0074926e8658e7fede97c230)

1 files changed, 62 insertions, 0 deletions

diff --git a/llvm/test/CodeGen/AArch64/funclet-match-add-sub-stack.ll b/llvm/test/CodeGen/AArch64/funclet-match-add-sub-stack.ll
new file mode 100644
index 00000000000..67e9c49675c
--- /dev/null
+++ b/llvm/test/CodeGen/AArch64/funclet-match-add-sub-stack.ll
@@ -0,0 +1,62 @@
+; RUN: llc -o - %s -mtriple=aarch64-windows | FileCheck %s
+; Check that the stack bump around a funclet is computed correctly in both the
+; prologue and epilogue in the case we have a MaxCallFrameSize > 0 and are doing alloca
+target datalayout = "e-m:w-p:64:64-i32:32-i64:64-i128:128-n32:64-S128"
+target triple = "aarch64-pc-windows-msvc19.25.28611"
+
+; // requires passing arguments on the stack
+; void test2(void*, int, int, int, int, int, int, int, int);
+;
+; // function with the funclet being checked
+; void test1(size_t bytes)
+; {
+;   // alloca forces a separate callee save bump and stack bump
+;   void *data = _alloca(bytes);
+;   try {
+;     test2(data, 0, 1, 2, 3, 4, 5, 6, 7);
+;   } catch (...) {
+;     // the funclet being checked
+;   }
+; }
+
+; CHECK-LABEL: ?catch$2@?0??test1@@YAX_K@Z@4HA
+; CHECK: sub sp, sp, #16
+; CHECK: add sp, sp, #16
+; Function Attrs: uwtable
+define dso_local void @"?test1@@YAX_K@Z"(i64 %0) #0 personality i8* bitcast (i32 (...)* @__CxxFrameHandler3 to i8*) {
+  %2 = alloca i64, align 8
+  %3 = alloca i8*, align 8
+  store i64 %0, i64* %2, align 8
+  %4 = load i64, i64* %2, align 8
+  %5 = alloca i8, i64 %4, align 16
+  store i8* %5, i8** %3, align 8
+  %6 = load i8*, i8** %3, align 8
+  invoke void @"?test2@@YAXPEAXHHHHHHHH@Z"(i8* %6, i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7)
+          to label %13 unwind label %7
+
+7:                                                ; preds = %1
+  %8 = catchswitch within none [label %9] unwind to caller
+
+9:                                                ; preds = %7
+  %10 = catchpad within %8 [i8* null, i32 64, i8* null]
+  catchret from %10 to label %11
+
+11:                                               ; preds = %9
+  br label %12
+
+12:                                               ; preds = %11, %13
+  ret void
+
+13:                                               ; preds = %1
+  br label %12
+}
+
+declare dso_local void @"?test2@@YAXPEAXHHHHHHHH@Z"(i8*, i32, i32, i32, i32, i32, i32, i32, i32) #1
+
+declare dso_local i32 @__CxxFrameHandler3(...)
+
+attributes #0 = { uwtable }
+
+!llvm.module.flags = !{!0}
+
+!0 = !{i32 1, !"wchar_size", i32 2}