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-rw-r--r--clang/lib/CodeGen/CodeGenFunction.cpp7
-rw-r--r--clang/test/CodeGen/stackrealign-main.c19
2 files changed, 26 insertions, 0 deletions
diff --git a/clang/lib/CodeGen/CodeGenFunction.cpp b/clang/lib/CodeGen/CodeGenFunction.cpp
index 030101d2f4e..d3b1bd77dc4 100644
--- a/clang/lib/CodeGen/CodeGenFunction.cpp
+++ b/clang/lib/CodeGen/CodeGenFunction.cpp
@@ -979,6 +979,13 @@ void CodeGenFunction::StartFunction(GlobalDecl GD,
if (FD->isMain())
Fn->addFnAttr(llvm::Attribute::NoRecurse);
+ // If a custom alignment is used, force realigning to this alignment on
+ // any main function which certainly will need it.
+ if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(D))
+ if ((FD->isMain() || FD->isMSVCRTEntryPoint()) &&
+ CGM.getCodeGenOpts().StackAlignment)
+ Fn->addFnAttr("stackrealign");
+
llvm::BasicBlock *EntryBB = createBasicBlock("entry", CurFn);
// Create a marker to make it easy to insert allocas into the entryblock
diff --git a/clang/test/CodeGen/stackrealign-main.c b/clang/test/CodeGen/stackrealign-main.c
new file mode 100644
index 00000000000..10b21bf548d
--- /dev/null
+++ b/clang/test/CodeGen/stackrealign-main.c
@@ -0,0 +1,19 @@
+// RUN: %clang_cc1 -triple i386-unknown-unknown -emit-llvm -o - -mstack-alignment=64 %s | FileCheck %s
+
+// CHECK-LABEL: define void @other()
+// CHECK: [[OTHER:#[0-9]+]]
+// CHECK: {
+void other(void) {}
+
+// CHECK-LABEL: define i32 @main(
+// CHECK: [[MAIN:#[0-9]+]]
+// CHECK: {
+int main(int argc, char **argv) {
+ other();
+ return 0;
+}
+
+// CHECK: attributes [[OTHER]] = { noinline nounwind optnone
+// CHECK-NOT: "stackrealign"
+// CHECK: }
+// CHECK: attributes [[MAIN]] = { noinline nounwind optnone {{.*}}"stackrealign"{{.*}} }
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