[PATCH] D78125: [AVR] Use the correct address space for non-prototyped function calls

[Ayke via Phabricator via cfe-commits]

aykevl created this revision.
aykevl added reviewers: dylanmckay, rjmccall, MaskRay.
aykevl added a project: LLVM.
Herald added subscribers: cfe-commits, Jim.
Herald added a project: clang.
aykevl edited the summary of this revision.

Some function declarations like this:

  void foo();

do not have a type declaration, for that you'd use:

  void foo(void);

Clang internally bitcasts the variadic function declaration to a function pointer, but doesn't use the correct address space on AVR. This commit fixes that.

This fix is necessary to let Clang compile compiler-rt for AVR.

---

Two remarks on this diff:

1. I wasn't sure whether there is a way to set the address space on a function. I at least couldn't seem to get it to work. If it is possible to set the address space, I think the fix is slightly wrong and should somehow get the address space from the function declaration instead of using `getProgramAddressSpace` (please let me know how or where to find this information).
2. I hoped there was a test file already where I could include this test, but at least CodeGen/address-space.c seemed a bit too complex to also test with AVR (for example, `int` is 16-bit on AVR).


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D78125

Files:
  clang/lib/CodeGen/CGExpr.cpp
  clang/test/CodeGen/address-space-avr.c


Index: clang/test/CodeGen/address-space-avr.c
===================================================================
--- /dev/null
+++ clang/test/CodeGen/address-space-avr.c
@@ -0,0 +1,9 @@
+// RUN: %clang_cc1 -triple avr -emit-llvm < %s | FileCheck %s
+
+// CHECK: define void @bar() addrspace(1)
+// CHECK: call addrspace(1) void bitcast (void (...) addrspace(1)* @foo to void (i16) addrspace(1)*)(i16 3)
+// CHECK: declare void @foo(...) addrspace(1)
+void foo();
+void bar(void) {
+	foo(3);
+}
Index: clang/lib/CodeGen/CGExpr.cpp
===================================================================
--- clang/lib/CodeGen/CGExpr.cpp
+++ clang/lib/CodeGen/CGExpr.cpp
@@ -5048,7 +5048,8 @@
   // to the function type.
   if (isa<FunctionNoProtoType>(FnType) || Chain) {
     llvm::Type *CalleeTy = getTypes().GetFunctionType(FnInfo);
-    CalleeTy = CalleeTy->getPointerTo();
+    int AS = getTypes().getDataLayout().getProgramAddressSpace();
+    CalleeTy = CalleeTy->getPointerTo(AS);
 
     llvm::Value *CalleePtr = Callee.getFunctionPointer();
     CalleePtr = Builder.CreateBitCast(CalleePtr, CalleeTy, "callee.knr.cast");


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