[DirectX] fix illegal behavior flag in module flags.

For DXIL which is based on llvm 3.7, max supported behavior flag for module flags is 6.
The commit will check all module flags, for behavior flag > 6, change it to 2 (Warning).

This is to fix the behavior flag part for #96912.

Author: python3kgae

llvm/lib/Target/DirectX/DXILPrepare.cpp

@@ -116,6 +116,31 @@ static void removeStringFunctionAttributes(Function &F,
   F.removeRetAttrs(DeadAttrs);
 }
 
+static void cleanModuleFlags(Module &M) {
+  NamedMDNode *MDFlags = M.getModuleFlagsMetadata();
+  if (!MDFlags)
+    return;
+
+  SmallVector<llvm::Module::ModuleFlagEntry> FlagEntries;
+  M.getModuleFlagsMetadata(FlagEntries);
+  bool Updated = false;
+  for (auto &Flag : FlagEntries) {
+    // llvm 3.7 only supports behavior up to AppendUnique.
+    if (Flag.Behavior <= Module::ModFlagBehavior::AppendUnique)
+      continue;
+    Flag.Behavior = Module::ModFlagBehavior::Warning;
+    Updated = true;
+  }
+
+  if (!Updated)
+    return;
+
+  MDFlags->eraseFromParent();
+
+  for (auto &Flag : FlagEntries)
+    M.addModuleFlag(Flag.Behavior, Flag.Key->getString(), Flag.Val);
+}
+
 class DXILPrepareModule : public ModulePass {
 
   static Value *maybeGenerateBitcast(IRBuilder<> &Builder,
@@ -213,6 +238,8 @@ class DXILPrepareModule : public ModulePass {
         }
       }
     }
+    // Remove flags not for DXIL.
+    cleanModuleFlags(M);
     return true;
   }
 

llvm/test/CodeGen/DirectX/clean-module-flags.ll

@@ -0,0 +1,20 @@
+; RUN: opt -S -dxil-prepare < %s | FileCheck %s
+
+; Make sure behavior flag > 6 is fixed.
+; CHECK-NOT: !{i32 7, !"frame-pointer", i32 2}
+; CHECK: !{i32 2, !"Dwarf Version", i32 4}
+; CHECK: !{i32 2, !"Debug Info Version", i32 3}
+
+; Function Attrs: nounwind memory(none)
+define void @main() local_unnamed_addr #0 {
+entry:
+  ret void
+}
+
+attributes #0 = { nounwind memory(none) }
+!llvm.module.flags = !{!0, !1, !2, !3}
+
+!0 = !{i32 1, !"wchar_size", i32 4}
+!1 = !{i32 7, !"frame-pointer", i32 2}
+!2 = !{i32 7, !"Dwarf Version", i32 4}
+!3 = !{i32 2, !"Debug Info Version", i32 3}

llvm/test/CodeGen/DirectX/clean-module-flags2.ll

@@ -0,0 +1,17 @@
+; RUN: opt -S -dxil-prepare < %s | FileCheck %s
+
+; CHECK: define void @main()
+; Make sure behavior flag > 6 is fixed.
+; CHECK-NOT:{i32 7, !"frame-pointer", i32 2}
+
+; Function Attrs: nounwind memory(none)
+define void @main() local_unnamed_addr #0 {
+entry:
+  ret void
+}
+
+attributes #0 = { nounwind memory(none) }
+!llvm.module.flags = !{!0, !1}
+
+!0 = !{i32 1, !"wchar_size", i32 4}
+!1 = !{i32 7, !"frame-pointer", i32 2}

llvm/test/tools/dxil-dis/di-compile-unit.ll

@@ -13,5 +13,5 @@ target triple = "dxil-unknown-shadermodel6.7-library"
 ; CHECK: !0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "Some Compiler", isOptimized: true, runtimeVersion: 0, emissionKind: 1, enums: !2)
 ; CHECK: !1 = !DIFile(filename: "di-compile-unit.src", directory: "/some-path")
 ; CHECK: !2 = !{}
-; CHECK: !3 = !{i32 7, !"Dwarf Version", i32 2}
-; CHECK: !4 = !{i32 2, !"Debug Info Version", i32 3}
+; CHECK: !{i32 2, !"Dwarf Version", i32 2}
+; CHECK: !{i32 2, !"Debug Info Version", i32 3}

llvm/test/tools/dxil-dis/di-subprogram.ll

@@ -12,8 +12,8 @@ target triple = "dxil-unknown-shadermodel6.7-library"
 !1 = !DIFile(filename: "some-source", directory: "some-path")
 !2 = !{}
 
-; CHECK: !3 = !{i32 7, !"Dwarf Version", i32 2}
-!3 = !{i32 7, !"Dwarf Version", i32 2}
+; CHECK: !3 = !{i32 2, !"Dwarf Version", i32 4}
+!3 = !{i32 2, !"Dwarf Version", i32 4}
 ; CHECK: !4 = !{i32 2, !"Debug Info Version", i32 3}
 !4 = !{i32 2, !"Debug Info Version", i32 3}
 

llvm/test/tools/dxil-dis/di-subrange.ll

@@ -4,7 +4,7 @@ target triple = "dxil-unknown-shadermodel6.7-library"
 !llvm.module.flags = !{!0, !1}
 !llvm.dbg.cu = !{!2}
 
-!0 = !{i32 7, !"Dwarf Version", i32 2}
+!0 = !{i32 2, !"Dwarf Version", i32 4}
 !1 = !{i32 2, !"Debug Info Version", i32 3}
 !2 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !3, producer: "xyz", isOptimized: true, runtimeVersion: 0, emissionKind: 1, retainedTypes: !4)
 !3 = !DIFile(filename: "input.hlsl", directory: "/some/path")
@@ -17,7 +17,7 @@ target triple = "dxil-unknown-shadermodel6.7-library"
 ; CHECK: !llvm.module.flags = !{!0, !1}
 ; CHECK: !llvm.dbg.cu = !{!2}
 
-; CHECK: !0 = !{i32 7, !"Dwarf Version", i32 2}
+; CHECK: !0 = !{i32 2, !"Dwarf Version", i32 4}
 ; CHECK: !1 = !{i32 2, !"Debug Info Version", i32 3}
 ; CHECK: !2 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !3, producer: "xyz", isOptimized: true, runtimeVersion: 0, emissionKind: 1, retainedTypes: !4)
 ; CHECK: !3 = !DIFile(filename: "input.hlsl", directory: "/some/path")