Apply workaround for Failed to evaluate function length in SEH unwind…

… info in aarch64
msys2 · Oct 3, 2023 · 1d30b39 · 1d30b39
1 parent a6610a1
commit 1d30b39
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diff --git a/mingw-w64-clang/0005-aarch64-unwind-seh.patch b/mingw-w64-clang/0005-aarch64-unwind-seh.patch
@@ -0,0 +1,75 @@
+From cef120a2e5abba06c1d7a699a4fd4a17e488d6af Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Martin=20Storsj=C3=B6?= <martin@martin.st>
+Date: Sun, 1 Oct 2023 00:08:23 +0300
+Subject: [PATCH] [AArch64] Disable loop alignment for Windows targets
+
+This should fix #66912. When emitting SEH unwind info, we need to
+be able to calculate the exact length of functions before alignments
+are fixed. Until that limitation is overcome, just disable all
+loop alignment on Windows targets.
+---
+ llvm/lib/MC/MCWin64EH.cpp                     |  3 +++
+ .../Target/AArch64/AArch64ISelLowering.cpp    |  7 ++++++-
+ llvm/test/CodeGen/AArch64/sched-loop-align.ll | 21 +++++++++++++++++++
+ 3 files changed, 30 insertions(+), 1 deletion(-)
+ create mode 100644 llvm/test/CodeGen/AArch64/sched-loop-align.ll
+
+diff --git a/lib/MC/MCWin64EH.cpp b/lib/MC/MCWin64EH.cpp
+index a2d61da722af870..bb3492bec8aad8a 100644
+--- a/lib/MC/MCWin64EH.cpp
++++ b/lib/MC/MCWin64EH.cpp
+@@ -1402,6 +1402,9 @@ static void ARM64EmitUnwindInfo(MCStreamer &streamer, WinEH::FrameInfo *info,
+     // here, but we'd have to emit the pdata, the xdata header, and the
+     // epilogue scopes later, since they depend on whether the we need to
+     // split the unwind data.
++    //
++    // If this is fixed, remove code in AArch64ISelLowering.cpp that
++    // disables loop alignment on Windows.
+     RawFuncLength = GetAbsDifference(streamer, info->FuncletOrFuncEnd,
+                                      info->Begin);
+   }
+diff --git a/lib/Target/AArch64/AArch64ISelLowering.cpp b/lib/Target/AArch64/AArch64ISelLowering.cpp
+index 932b36587f0694e..46064bc7e46783f 100644
+--- a/lib/Target/AArch64/AArch64ISelLowering.cpp
++++ b/lib/Target/AArch64/AArch64ISelLowering.cpp
+@@ -1051,7 +1051,12 @@ AArch64TargetLowering::AArch64TargetLowering(const TargetMachine &TM,
+   // Set required alignment.
+   setMinFunctionAlignment(Align(4));
+   // Set preferred alignments.
+-  setPrefLoopAlignment(STI.getPrefLoopAlignment());
++
++  // Don't align loops on Windows. The SEH unwind info generation needs to
++  // know the exact length of functions before the alignments have been
++  // expanded.
++  if (!Subtarget->isTargetWindows())
++    setPrefLoopAlignment(STI.getPrefLoopAlignment());
+   setMaxBytesForAlignment(STI.getMaxBytesForLoopAlignment());
+   setPrefFunctionAlignment(STI.getPrefFunctionAlignment());
+
+diff --git a/test/CodeGen/AArch64/sched-loop-align.ll b/test/CodeGen/AArch64/sched-loop-align.ll
+new file mode 100644
+index 000000000000000..5b8e42c2790a439
+--- /dev/null
++++ b/test/CodeGen/AArch64/sched-loop-align.ll
+@@ -0,0 +1,21 @@
++; RUN: llc < %s -mtriple=aarch64-windows | FileCheck %s --check-prefix=WINDOWS
++; RUN: llc < %s -mtriple=aarch64-linux | FileCheck %s --check-prefix=LINUX
++
++define dso_local void @b() #0 {
++entry:
++  br label %for.cond
++
++for.cond:
++  tail call void @a()
++  br label %for.cond
++}
++
++declare dso_local void @a(...)
++
++attributes #0 = { noreturn nounwind uwtable "tune-cpu"="cortex-a53" }
++
++; LINUX-LABEL: b:
++; LINUX: .p2align 4
++
++; WINDOWS-LABEL: b:
++; WINDOWS-NOT: .p2align
diff --git a/mingw-w64-clang/PKGBUILD b/mingw-w64-clang/PKGBUILD
@@ -27,7 +27,7 @@ _version=17.0.1
 _rc=
 _tag=llvmorg-${_version}${_rc}
 pkgver=${_version}${_rc/-/}
-pkgrel=1
+pkgrel=2
 pkgdesc="C language family frontend for LLVM (mingw-w64)"
 arch=('any')
 mingw_arch=('mingw32' 'mingw64' 'ucrt64' 'clang64' 'clang32' 'clangarm64')
@@ -63,7 +63,8 @@ source=("${_url}/llvm-${pkgver}.src.tar.xz"{,.sig}
         "0004-enable-emutls-for-mingw.patch"
         "0101-link-pthread-with-mingw.patch"
         "0102-Rename-flang-new-flang-experimental-exec-to-flang.patch"
-        "0303-ignore-new-bfd-options.patch")
+        "0303-ignore-new-bfd-options.patch"
+        "0005-aarch64-unwind-seh.patch")
 # Some patch notes :)
 #0001-0099 -> llvm
 #0101-0199 -> clang
@@ -89,7 +90,8 @@ sha256sums=('6acbd59b0a5156b61e82157915ee962a56e13d97aa5fcaa959b68809290893d1'
             '5f86e542dd1ec92b2fe06ee59061c3e23512df7bafabe82206f2b7d80b81836b'
             '715cb8862753854b2d9256e0b70003e2d1f57083d83eaeaf5a095fc72b8a4e26'
             '2770cadf8ccf6b31aece6aee8f76dceb71e6e9d01fdf3be74c3743480ce34899'
-            'de631ab199a6fe83b3f695350bffaad067a2f95fc2ba9c8fe57dc85665d3653c')
+            'de631ab199a6fe83b3f695350bffaad067a2f95fc2ba9c8fe57dc85665d3653c'
+            '23b92a36f1623c3bd03fac831457597fc28276b9fd442cff6c962500e8cbbbc4')
 validpgpkeys=('B6C8F98282B944E3B0D5C2530FC3042E345AD05D'  # Hans Wennborg, Google.
               '474E22316ABF4785A88C6E8EA2C794A986419D8A'  # Tom Stellard
               'D574BD5D1D0E98895E3BF90044F2485E45D59042') # Tobias Hieta
@@ -124,7 +126,8 @@ prepare() {
   # Patch llvm
   cd "${srcdir}/llvm"
   apply_patch_with_msg \
-    "0001-Fix-GetHostTriple-for-mingw-w64-in-msys.patch"
+    "0001-Fix-GetHostTriple-for-mingw-w64-in-msys.patch" \
+    "0005-aarch64-unwind-seh.patch"
 
   if (( ! _clangprefix )); then
     apply_patch_with_msg \