From 8284fd6acaa356a0aa0becd1e3888efb348cd23c Mon Sep 17 00:00:00 2001
From: Andrey Turetskiy <andrey.turetskiy@gmail.com>
Date: Wed, 10 Feb 2016 11:58:46 +0000
Subject: [PATCH] [X86] Fix stack alignment for MCU target (Clang part), by
 Anton Nadolskiy.

This patch fixes stack alignments for MCU (should be aligned to 4 bytes).

Differential Revision: http://reviews.llvm.org/D15647



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@260376 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/clang/Basic/TargetInfo.h |  3 +++
 lib/AST/ASTContext.cpp           |  4 ++--
 lib/Basic/Targets.cpp            |  9 ++++++++
 test/CodeGen/iamcu-abi.c         | 38 ++++++++++++++++++++++++++++++++
 4 files changed, 52 insertions(+), 2 deletions(-)
 create mode 100644 test/CodeGen/iamcu-abi.c

diff --git a/include/clang/Basic/TargetInfo.h b/include/clang/Basic/TargetInfo.h
index dd5039898d..0d832f5f7f 100644
--- a/include/clang/Basic/TargetInfo.h
+++ b/include/clang/Basic/TargetInfo.h
@@ -940,6 +940,9 @@ public:
     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/lib/AST/ASTContext.cpp b/lib/AST/ASTContext.cpp
index 06fb46e2f7..eba35786e8 100644
--- a/lib/AST/ASTContext.cpp
+++ b/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/lib/Basic/Targets.cpp b/lib/Basic/Targets.cpp
index 3788a82a5f..5501ceb702 100644
--- a/lib/Basic/Targets.cpp
+++ b/lib/Basic/Targets.cpp
@@ -3807,6 +3807,8 @@ public:
       : 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 @@ public:
     Builder.defineMacro("__iamcu");
     Builder.defineMacro("__iamcu__");
   }
+
+  bool allowsLargerPreferedTypeAlignment() const override {
+    return false;
+  }
 };
 
 // RTEMS Target
@@ -7491,6 +7497,9 @@ public:
     // R0=ExceptionPointerRegister R1=ExceptionSelectorRegister
     return (RegNo < 2)? RegNo : -1;
   }
+  bool allowsLargerPreferedTypeAlignment() const override {
+    return false;
+  }
 };
 
 const Builtin::Info XCoreTargetInfo::BuiltinInfo[] = {
diff --git a/test/CodeGen/iamcu-abi.c b/test/CodeGen/iamcu-abi.c
new file mode 100644
index 0000000000..897d475d49
--- /dev/null
+++ b/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);
+}
-- 
2.40.0