Merge pull request #10933 from aschwaighofer/swift-4.0-branch-07-1100-2017-fix_alignment_indirect_byval_args

[4.0] IRGen: Make sure to use the C function type's alignment for indirect byval arguments

Author: najacque

lib/IRGen/GenCall.cpp

@@ -976,8 +976,9 @@ llvm::Type *SignatureExpansion::expandExternalSignatureTypes() {
       auto paramTy = getSILFuncConventions().getSILType(param);
       auto &paramTI = cast<FixedTypeInfo>(IGM.getTypeInfo(paramTy));
       if (AI.getIndirectByVal())
-        addByvalArgumentAttributes(IGM, Attrs, getCurParamIndex(),
-                                   paramTI.getFixedAlignment());
+        addByvalArgumentAttributes(
+            IGM, Attrs, getCurParamIndex(),
+            Alignment(AI.getIndirectAlign().getQuantity()));
       addPointerParameter(paramTI.getStorageType());
       break;
     }
@@ -1851,6 +1852,16 @@ static void externalizeArguments(IRGenFunction &IGF, const Callee &callee,
       auto &ti = cast<LoadableTypeInfo>(IGF.getTypeInfo(paramType));
       Address addr = ti.allocateStack(IGF, paramType, false,
                                       "indirect-temporary").getAddress();
+      // Set at least the alignment the ABI expects.
+      if (AI.getIndirectByVal()) {
+        auto ABIAlign = AI.getIndirectAlign();
+        if (ABIAlign > addr.getAlignment()) {
+          auto *AS = cast<llvm::AllocaInst>(addr.getAddress());
+          AS->setAlignment(ABIAlign.getQuantity());
+          addr = Address(addr.getAddress(), Alignment(ABIAlign.getQuantity()));
+        }
+      }
+
       ti.initialize(IGF, in, addr);
 
       out.add(addr.getAddress());

test/IRGen/Inputs/c_functions.h

@@ -9,3 +9,14 @@ static inline void test_my_log() {
   __attribute__((internal_linkage)) static const char fmt[] = "foobar";
   use(fmt);
 }
+
+extern void useInt(unsigned int);
+
+typedef struct {
+    unsigned int val[8];
+} a_thing;
+
+static inline void log_a_thing(const a_thing thing) {
+ useInt(thing.val[0]);
+ useInt(thing.val[7]);
+}

test/IRGen/abitypes.swift

@@ -107,7 +107,7 @@ class Foo {
   }
 
   // Ensure that MyRect is passed as an indirect-byval on x86_64 because we run out of registers for direct arguments
-  // x86_64-macosx: define hidden float @_T08abitypes3FooC25getXFromRectIndirectByVal{{[_0-9a-zA-Z]*}}FTo(i8*, i8*, float, float, float, float, float, float, float, %TSC6MyRectV* byval align 4) unnamed_addr {{.*}} {
+  // x86_64-macosx: define hidden float @_T08abitypes3FooC25getXFromRectIndirectByVal{{[_0-9a-zA-Z]*}}FTo(i8*, i8*, float, float, float, float, float, float, float, %TSC6MyRectV* byval align 8) unnamed_addr {{.*}} {
   dynamic func getXFromRectIndirectByVal(_: Float, second _: Float, 
                                        third _: Float, fourth _: Float,
                                        fifth _: Float, sixth _: Float,
@@ -120,8 +120,8 @@ class Foo {
   // x86_64-macosx: define hidden swiftcc float @_T08abitypes3FooC25getXFromRectIndirectSwift{{[_0-9a-zA-Z]*}}F(i64, i64, %T8abitypes3FooC* swiftself) {{.*}} {
   func getXFromRectIndirectSwift(_ r: MyRect) -> Float {
     let f : Float = 1.0
-    // x86_64-macosx: [[TEMP:%.*]] = alloca [[TEMPTYPE:%.*]], align 4
-    // x86_64-macosx: [[RESULT:%.*]] = call float bitcast (void ()* @objc_msgSend to float (i8*, i8*, float, float, float, float, float, float, float, [[TEMPTYPE]]*)*)(i8* %{{.*}}, i8* %{{.*}}, float 1.000000e+00, float 1.000000e+00, float 1.000000e+00, float 1.000000e+00, float 1.000000e+00, float 1.000000e+00, float 1.000000e+00, [[TEMPTYPE]]* byval align 4 [[TEMP]])
+    // x86_64-macosx: [[TEMP:%.*]] = alloca [[TEMPTYPE:%.*]], align 8
+    // x86_64-macosx: [[RESULT:%.*]] = call float bitcast (void ()* @objc_msgSend to float (i8*, i8*, float, float, float, float, float, float, float, [[TEMPTYPE]]*)*)(i8* %{{.*}}, i8* %{{.*}}, float 1.000000e+00, float 1.000000e+00, float 1.000000e+00, float 1.000000e+00, float 1.000000e+00, float 1.000000e+00, float 1.000000e+00, [[TEMPTYPE]]* byval align 8 [[TEMP]])
     // x86_64-macosx: ret float [[RESULT]]
     return getXFromRectIndirectByVal(f, second: f, third: f, fourth: f, fifth: f, sixth: f, seventh: f, withRect: r);
   }

test/IRGen/c_functions.swift

@@ -12,3 +12,14 @@ func testOverloaded() {
   // CHECK: call void @{{.*}}test_my_log
   test_my_log()
 } // CHECK: {{^}$}}
+
+func test_indirect_by_val_alignment() {
+  let x = a_thing()
+  log_a_thing(x)
+}
+
+// CHECK-LABEL: define hidden swiftcc void  @_T011c_functions30test_indirect_by_val_alignmentyyF()
+// CHECK: %indirect-temporary = alloca %TSC7a_thingV, align [[ALIGN:[0-9]+]]
+// CHECK: [[CAST:%.*]] = bitcast %TSC7a_thingV* %indirect-temporary to %struct.a_thing*
+// CHECK: call void @log_a_thing(%struct.a_thing* byval align [[ALIGN]] [[CAST]])
+// CHECK: define internal void @log_a_thing(%struct.a_thing* byval align [[ALIGN]]