FIX: do not ignore a return value if array/vector/struct type

This should solve issues #53 and #54.
Thanks Shaobo for reporting the problem.

src/DsaLocal.cc

@@ -1214,8 +1214,12 @@ void IntraBlockBuilder::visitIntToPtrInst(IntToPtrInst &I) {
 
 void IntraBlockBuilder::visitReturnInst(ReturnInst &RI) {
   Value *v = RI.getReturnValue();
-  if (!v || isSkip(*v))
+
+  // We don't skip the return value if its type is a
+  // struct/vector/array because it can contain pointers inside.
+  if (!v || (isSkip(*v) && !isa<CompositeType>(RI.getReturnValue()->getType()))) {
     return;
+  }
 
   sea_dsa::Cell c = valueCell(*v);
   if (c.isNull())

tests/c/test-ret-struct.c

@@ -0,0 +1,22 @@
+#include <assert.h> 
+
+int* A;
+
+typedef struct {
+  int* a;
+  long b;
+} S;
+
+S foo() {
+  S x = {A, 2L};
+  assert(1);
+  return x;
+}
+
+int main() {
+  int a = 1;
+  A = &a;
+  S y = foo();
+  assert(*(y.a) == 1);
+  return 0;
+}

tests/expected_graphs/test-ret-struct.c.main.mem.dot

@@ -0,0 +1,38 @@
+digraph unnamed {
+	graph [center=true, ratio=true, bgcolor=lightgray, fontname=Helvetica];
+	node  [fontname=Helvetica, fontsize=11];
+
+	Node0x7f9ac0506130 [shape=record,label="{\{0:i32*\}:MR|{<s0>\<0, unknown\>}}"];
+	Node0x7f9ac0506210 [shape=record,label="{\{void\}:}"];
+	Node0x7f9ac05062a0 [shape=record,label="{\{void\}:}"];
+	Node0x7f9ac05063a0 [shape=record,label="{\{void\}:}"];
+	Node0x7f9ac0506480 [shape=record,label="{\{0:i32\}:SM}"];
+	Node0x7f9ac05066c0 [shape=record,label="{\{0:i32*,8:i64\}:SMR|{<s0>\<0, unknown\>}}"];
+	Node0x7f9ac0506880 [shape=record,label="{\{0:i32*,8:i64\}:SMR|{<s0>\<0, unknown\>}}"];
+	Node0x7f9ac0506a40 [shape=record,label="{\{0:i32\}:SMR}"];
+	Node0x7f9ac040c638 [shape=plaintext, label ="  %4 = call \{ i32*, i64 \} @foo()"];
+	Node0x7f9ac040c638 -> Node0x7f9ac0506880[arrowtail=tee,label="0",fontsize=8,color=purple];
+	Node0x7f9ac0500048 [shape=plaintext, label ="  %8 = getelementptr inbounds \{ i32*, i64 \}, \{ i32*, i64 \}* %5, i32 0, i32 1"];
+	Node0x7f9ac0500048 -> Node0x7f9ac05066c0[arrowtail=tee,label="8",fontsize=8,color=purple];
+	Node0x7f9ac040b088 [shape=plaintext, label =".str.1"];
+	Node0x7f9ac040b088 -> Node0x7f9ac05063a0[arrowtail=tee,label="0",fontsize=8,color=purple];
+	Node0x7f9ac040ac38 [shape=plaintext, label ="A"];
+	Node0x7f9ac040ac38 -> Node0x7f9ac0506130[arrowtail=tee,label="0",fontsize=8,color=purple];
+	Node0x7f9ac040c7b8 [shape=plaintext, label ="  %7 = extractvalue \{ i32*, i64 \} %4, 0"];
+	Node0x7f9ac040c7b8 -> Node0x7f9ac0506a40[arrowtail=tee,label="0",fontsize=8,color=purple];
+	Node0x7f9ac040c3c8 [shape=plaintext, label ="  %1 = alloca i32, align 4"];
+	Node0x7f9ac040c3c8 -> Node0x7f9ac0506480[arrowtail=tee,label="0",fontsize=8,color=purple];
+	Node0x7f9ac040c428 [shape=plaintext, label ="  %2 = alloca i32, align 4"];
+	Node0x7f9ac040c428 -> Node0x7f9ac0506a40[arrowtail=tee,label="0",fontsize=8,color=purple];
+	Node0x7f9ac040c488 [shape=plaintext, label ="  %3 = alloca %struct.S, align 8"];
+	Node0x7f9ac040c488 -> Node0x7f9ac05066c0[arrowtail=tee,label="0",fontsize=8,color=purple];
+	Node0x7f9ac05002a8 [shape=plaintext, label ="  %11 = load i32*, i32** %10, align 8"];
+	Node0x7f9ac05002a8 -> Node0x7f9ac0506a40[arrowtail=tee,label="0",fontsize=8,color=purple];
+	Node0x7f9ac040afa8 [shape=plaintext, label =".str"];
+	Node0x7f9ac040afa8 -> Node0x7f9ac05062a0[arrowtail=tee,label="0",fontsize=8,color=purple];
+	Node0x7f9ac040aeb8 [shape=plaintext, label ="__func__.main"];
+	Node0x7f9ac040aeb8 -> Node0x7f9ac0506210[arrowtail=tee,label="0",fontsize=8,color=purple];
+	Node0x7f9ac0506130:s0 -> Node0x7f9ac0506a40[arrowtail=tee,label="0",fontsize=8];
+	Node0x7f9ac05066c0:s0 -> Node0x7f9ac0506a40[arrowtail=tee,label="0",fontsize=8];
+	Node0x7f9ac0506880:s0 -> Node0x7f9ac0506a40[arrowtail=tee,label="0",fontsize=8];
+}

tests/test-ret-struct.ll

@@ -0,0 +1,90 @@
+; RUN: %seadsa  %butd_dsa --sea-dsa-dot %s --sea-dsa-dot-outdir=%T/test-ret-struct.ll
+; RUN: %cmp-graphs %tests/test-ret-struct.c.main.mem.dot %T/test-ret-struct.ll/main.mem.dot | OutputCheck %s -d --comment=";"
+; CHECK: ^OK$
+
+
+; ModuleID = 'test-shaobo.1.c'
+source_filename = "test-shaobo.1.c"
+target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-apple-macosx10.14.0"
+
+%struct.S = type { i32*, i64 }
+
+@A = common global i32* null, align 8
+@__func__.main = private unnamed_addr constant [5 x i8] c"main\00", align 1
+@.str = private unnamed_addr constant [16 x i8] c"test-shaobo.1.c\00", align 1
+@.str.1 = private unnamed_addr constant [12 x i8] c"*(y.a) == 1\00", align 1
+
+; Function Attrs: noinline nounwind optnone ssp uwtable
+define { i32*, i64 } @foo() #0 {
+  %1 = alloca %struct.S, align 8
+  %2 = alloca %struct.S, align 8
+  %3 = getelementptr inbounds %struct.S, %struct.S* %2, i32 0, i32 0
+  %4 = load i32*, i32** @A, align 8
+  store i32* %4, i32** %3, align 8
+  %5 = getelementptr inbounds %struct.S, %struct.S* %2, i32 0, i32 1
+  store i64 2, i64* %5, align 8
+  %6 = bitcast %struct.S* %1 to i8*
+  %7 = bitcast %struct.S* %2 to i8*
+  call void @llvm.memcpy.p0i8.p0i8.i64(i8* %6, i8* %7, i64 16, i32 8, i1 false)
+  %8 = bitcast %struct.S* %1 to { i32*, i64 }*
+  %9 = load { i32*, i64 }, { i32*, i64 }* %8, align 8
+  ret { i32*, i64 } %9
+}
+
+; Function Attrs: argmemonly nounwind
+declare void @llvm.memcpy.p0i8.p0i8.i64(i8* nocapture writeonly, i8* nocapture readonly, i64, i32, i1) #1
+
+; Function Attrs: noinline nounwind optnone ssp uwtable
+define i32 @main() #0 {
+  %1 = alloca i32, align 4
+  %2 = alloca i32, align 4
+  %3 = alloca %struct.S, align 8
+  store i32 0, i32* %1, align 4
+  store i32 1, i32* %2, align 4
+  store i32* %2, i32** @A, align 8
+  %4 = call { i32*, i64 } @foo()
+  %5 = bitcast %struct.S* %3 to { i32*, i64 }*
+  %6 = getelementptr inbounds { i32*, i64 }, { i32*, i64 }* %5, i32 0, i32 0
+  %7 = extractvalue { i32*, i64 } %4, 0
+  store i32* %7, i32** %6, align 8
+  %8 = getelementptr inbounds { i32*, i64 }, { i32*, i64 }* %5, i32 0, i32 1
+  %9 = extractvalue { i32*, i64 } %4, 1
+  store i64 %9, i64* %8, align 8
+  %10 = getelementptr inbounds %struct.S, %struct.S* %3, i32 0, i32 0
+  %11 = load i32*, i32** %10, align 8
+  %12 = load i32, i32* %11, align 4
+  %13 = icmp eq i32 %12, 1
+  %14 = xor i1 %13, true
+  %15 = zext i1 %14 to i32
+  %16 = sext i32 %15 to i64
+  %17 = icmp ne i64 %16, 0
+  br i1 %17, label %18, label %20
+
+; <label>:18:                                     ; preds = %0
+  call void @__assert_rtn(i8* getelementptr inbounds ([5 x i8], [5 x i8]* @__func__.main, i32 0, i32 0), i8* getelementptr inbounds ([16 x i8], [16 x i8]* @.str, i32 0, i32 0), i32 20, i8* getelementptr inbounds ([12 x i8], [12 x i8]* @.str.1, i32 0, i32 0)) #3
+  unreachable
+                                                  ; No predecessors!
+  br label %21
+
+; <label>:20:                                     ; preds = %0
+  br label %21
+
+; <label>:21:                                     ; preds = %20, %19
+  ret i32 0
+}
+
+; Function Attrs: noreturn
+declare void @__assert_rtn(i8*, i8*, i32, i8*) #2
+
+attributes #0 = { noinline nounwind optnone ssp uwtable "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="penryn" "target-features"="+cx16,+fxsr,+mmx,+sse,+sse2,+sse3,+sse4.1,+ssse3,+x87" "unsafe-fp-math"="false" "use-soft-float"="false" }
+attributes #1 = { argmemonly nounwind }
+attributes #2 = { noreturn "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="true" "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="penryn" "target-features"="+cx16,+fxsr,+mmx,+sse,+sse2,+sse3,+sse4.1,+ssse3,+x87" "unsafe-fp-math"="false" "use-soft-float"="false" }
+attributes #3 = { noreturn }
+
+!llvm.module.flags = !{!0, !1}
+!llvm.ident = !{!2}
+
+!0 = !{i32 1, !"wchar_size", i32 4}
+!1 = !{i32 7, !"PIC Level", i32 2}
+!2 = !{!"clang version 5.0.0 (tags/RELEASE_500/final)"}