llvm-reduce: Fix losing callsite attributes when removing arguments

The attribute APIs make this cumbersome. There seem to be missing
overloads using AttrBuilder for the function attrs. Plus there doesn't
seem to be a direct way to set the function attrs on the call.

Author: arsenm

llvm/test/tools/llvm-reduce/reduce-arguments-x86_intrcc.ll

@@ -20,7 +20,7 @@ declare x86_intrcc void @extern_decl(ptr byval(i32), i32, i32)
 
 ; INTERESTING-LABEL: void @callsite(
 ; INTERESTING: call
-; REDUCED: call x86_intrcc void @func(ptr %k, i32 %other.keep)
+; REDUCED: call x86_intrcc void @func(ptr byval(i32) %k, i32 %other.keep)
 define void @callsite(ptr %k, i32 %other.keep, i32 %other.drop) {
   call x86_intrcc void @func(ptr byval(i32) %k, i32 %other.keep, i32 %other.drop)
   ret void

llvm/test/tools/llvm-reduce/remove-argument-preserve-attributes.ll

@@ -0,0 +1,55 @@
+; Check that when removing arguments, existing callsite attributes are preserved
+
+; RUN: llvm-reduce --abort-on-invalid-reduction --delta-passes=arguments --test FileCheck --test-arg --check-prefixes=INTERESTING --test-arg %s --test-arg --input-file %s -o %t
+; RUN: FileCheck --check-prefixes=RESULT %s < %t
+
+; INTERESTING-LABEL: define void @callee0(
+define void @callee0(ptr %interesting0, ptr %interesting1, i32 %uninteresting2) {
+  ret void
+}
+
+; INTERESTING-LABEL: define void @callee1(
+define void @callee1(ptr byval(i64) %interesting0, ptr %interesting1, i32 %uninteresting2) {
+  ret void
+}
+
+; INTERESTING-LABEL: define void @caller0(
+
+; INTERESTING: byval
+; INTERESTING-SAME: "some-attr"
+
+; INTERESTING: byval
+; INTERESTING-SAME: "more-attr"
+
+; RESULT-LABEL: define void @caller0(ptr %val0) {
+; RESULT: call void @callee0(ptr byval(i32) %val0, ptr "some-attr" %alloca0) #0
+; RESULT: call void @callee1(ptr byval(i64) %alloca1, ptr "more-attr" %alloca1) #1
+define void @caller0(ptr %val0, i32 %val1) {
+  %alloca0 = alloca i32
+  %alloca1 = alloca i64
+  call void @callee0(ptr byval(i32) %val0, ptr "some-attr" %alloca0, i32 %val1) nounwind memory(none) "a-func-attr"
+  call void @callee1(ptr byval(i64) %alloca1, ptr "more-attr" %alloca1, i32 9) "val-func-attr="="something"
+  ret void
+}
+
+; RESULT-LABEL: define ptr @callee2() {
+; RESULT-NEXT: ret ptr null
+define ptr @callee2(ptr %val0, i32 %b) {
+  store i32 %b, ptr %val0
+  ret ptr %val0
+}
+
+; Make sure ret attributes are preserved
+; INTERESTING: define ptr @caller1(
+; INTERESTING: call
+
+; RESULT-LABEL: define ptr @caller1() {
+; RESULT: %ret = call align 4 "ret-attr" ptr @callee2()
+
+define ptr @caller1(ptr %val0, i32 %val1) {
+  %ret = call align 4 "ret-attr" ptr @callee2(ptr %val0, i32 %val1)
+  ret ptr %ret
+}
+
+; RESULT: attributes #0 = { nounwind memory(none) "a-func-attr" }
+; RESULT: attributes #1 = { "val-func-attr="="something" }

llvm/tools/llvm-reduce/deltas/ReduceArguments.cpp

@@ -39,6 +39,8 @@ static bool callingConvRequiresArgument(const Function &F,
 /// Goes over OldF calls and replaces them with a call to NewF
 static void replaceFunctionCalls(Function &OldF, Function &NewF,
                                  const std::set<int> &ArgIndexesToKeep) {
+  LLVMContext &Ctx = OldF.getContext();
+
   const auto &Users = OldF.users();
   for (auto I = Users.begin(), E = Users.end(); I != E; )
     if (auto *CI = dyn_cast<CallInst>(*I++)) {
@@ -47,12 +49,30 @@ static void replaceFunctionCalls(Function &OldF, Function &NewF,
       if (CI->getCalledFunction() != &OldF)
         continue;
       SmallVector<Value *, 8> Args;
-      for (auto ArgI = CI->arg_begin(), E = CI->arg_end(); ArgI != E; ++ArgI)
-        if (ArgIndexesToKeep.count(ArgI - CI->arg_begin()))
+      SmallVector<AttrBuilder, 8> ArgAttrs;
+
+      for (auto ArgI = CI->arg_begin(), E = CI->arg_end(); ArgI != E; ++ArgI) {
+        unsigned ArgIdx = ArgI - CI->arg_begin();
+        if (ArgIndexesToKeep.count(ArgIdx)) {
           Args.push_back(*ArgI);
+          ArgAttrs.emplace_back(Ctx, CI->getParamAttributes(ArgIdx));
+        }
+      }
 
+      // FIXME: Losing bundles, fast math flags and metadata
       CallInst *NewCI = CallInst::Create(&NewF, Args);
       NewCI->setCallingConv(NewF.getCallingConv());
+
+      AttrBuilder CallSiteAttrs(Ctx, CI->getAttributes().getFnAttrs());
+      NewCI->setAttributes(
+          AttributeList::get(Ctx, AttributeList::FunctionIndex, CallSiteAttrs));
+      NewCI->addRetAttrs(AttrBuilder(Ctx, CI->getRetAttributes()));
+
+      unsigned AttrIdx = 0;
+      for (auto ArgI = NewCI->arg_begin(), E = NewCI->arg_end(); ArgI != E;
+           ++ArgI, ++AttrIdx)
+        NewCI->addParamAttrs(AttrIdx, ArgAttrs[AttrIdx]);
+
       if (!CI->use_empty())
         CI->replaceAllUsesWith(NewCI);
       ReplaceInstWithInst(CI, NewCI);