[X86] Fix stack alignment for MCU target (Clang part), by Anton Nadolskiy.

aturetsk · aturetsk · commit db6655fd902a · 2016-02-10T11:58:46.000Z
This patch fixes stack alignments for MCU (should be aligned to 4 bytes). Differential Revision: http://reviews.llvm.org/D15647 llvm-svn: 260376
diff --git a/clang/include/clang/Basic/TargetInfo.h b/clang/include/clang/Basic/TargetInfo.h
@@ -940,6 +940,9 @@ class TargetInfo : public RefCountedBase<TargetInfo> {
     return false;
   }
 
+  /// \brief Whether target allows to overalign ABI-specified prefered alignment
+  virtual bool allowsLargerPreferedTypeAlignment() const { return true; }
+
 protected:
   virtual uint64_t getPointerWidthV(unsigned AddrSpace) const {
     return PointerWidth;
diff --git a/clang/lib/AST/ASTContext.cpp b/clang/lib/AST/ASTContext.cpp
@@ -1904,8 +1904,8 @@ unsigned ASTContext::getPreferredTypeAlign(const Type *T) const {
   if (T->isMemberPointerType())
     return getPreferredTypeAlign(getPointerDiffType().getTypePtr());
 
-  if (Target->getTriple().getArch() == llvm::Triple::xcore)
-    return ABIAlign;  // Never overalign on XCore.
+  if (!Target->allowsLargerPreferedTypeAlignment())
+    return ABIAlign;
 
   // Double and long long should be naturally aligned if possible.
   if (const ComplexType *CT = T->getAs<ComplexType>())
diff --git a/clang/lib/Basic/Targets.cpp b/clang/lib/Basic/Targets.cpp
@@ -3807,6 +3807,8 @@ class MicrosoftX86_32TargetInfo : public WindowsX86_32TargetInfo {
       : WindowsX86_32TargetInfo(Triple) {
     LongDoubleWidth = LongDoubleAlign = 64;
     LongDoubleFormat = &llvm::APFloat::IEEEdouble;
+    DataLayoutString =
+        "e-m:e-p:32:32-i64:32-f64:32-f128:32-n8:16:32-a:0:32-S32";
   }
   void getTargetDefines(const LangOptions &Opts,
                         MacroBuilder &Builder) const override {
@@ -3926,6 +3928,10 @@ class MCUX86_32TargetInfo : public X86_32TargetInfo {
     Builder.defineMacro("__iamcu");
     Builder.defineMacro("__iamcu__");
   }
+
+  bool allowsLargerPreferedTypeAlignment() const override {
+    return false;
+  }
 };
 
 // RTEMS Target
@@ -7491,6 +7497,9 @@ class XCoreTargetInfo : public TargetInfo {
     // R0=ExceptionPointerRegister R1=ExceptionSelectorRegister
     return (RegNo < 2)? RegNo : -1;
   }
+  bool allowsLargerPreferedTypeAlignment() const override {
+    return false;
+  }
 };
 
 const Builtin::Info XCoreTargetInfo::BuiltinInfo[] = {
diff --git a/clang/test/CodeGen/iamcu-abi.c b/clang/test/CodeGen/iamcu-abi.c
@@ -0,0 +1,38 @@
+// RUN: %clang_cc1 -triple i386-pc-elfiamcu -emit-llvm -o - %s | FileCheck %s
+
+// CHECK: target datalayout = "e-m:e-p:32:32-i64:32-f64:32-f128:32-n8:16:32-a:0:32-S32"
+// CHECK: target triple = "i386-pc-elfiamcu"
+
+
+void food(double *d);
+void fooll(long long *ll);
+void fooull(unsigned long long *ull);
+void foold(long double *ld);
+
+// CHECK-LABEL: define void @testdouble()
+// CHECK: alloca double, align 4
+void testdouble() {
+  double d = 2.0;
+  food(&d);
+}
+
+// CHECK-LABEL: define void @testlonglong()
+// CHECK: alloca i64, align 4
+void testlonglong() {
+  long long ll = 2;
+  fooll(&ll);
+}
+
+// CHECK-LABEL: define void @testunsignedlonglong()
+// CHECK: alloca i64, align 4
+void testunsignedlonglong() {
+  unsigned long long ull = 2;
+  fooull(&ull);	
+}
+
+// CHECK-LABEL: define void @testlongdouble()
+// CHECK: alloca double, align 4
+void testlongdouble() {
+  long double ld = 2.0;
+  foold(&ld);
+}

Original file line number	Diff line number	Diff line change
`@@ -940,6 +940,9 @@ class TargetInfo : public RefCountedBase<TargetInfo> {`
`940`	`940`	`return false;`
`941`	`941`	`}`
`942`	`942`
	`943`	`+ /// \brief Whether target allows to overalign ABI-specified prefered alignment`
	`944`	`+ virtual bool allowsLargerPreferedTypeAlignment() const { return true; }`
	`945`	`+`
`943`	`946`	`protected:`
`944`	`947`	`virtual uint64_t getPointerWidthV(unsigned AddrSpace) const {`
`945`	`948`	`return PointerWidth;`