Add a new ABI to support cmse_nonsecure_call

This commit adds a new ABI to be selected via `extern
"C-cmse-nonsecure-call"` on function pointers in order for the compiler to
apply the corresponding cmse_nonsecure_call callsite attribute.
For Armv8-M targets supporting TrustZone-M, this will perform a
non-secure function call by saving, clearing and calling a non-secure
function pointer using the BLXNS instruction.

See the page on the unstable book for details.

Signed-off-by: Hugues de Valon <hugues.devalon@arm.com>

1 files changed, 8 insertions, 0 deletions

diff --git a/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp b/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp
index 1d89fc80496..4118e930745 100644
--- a/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp
+++ b/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp
@@ -216,6 +216,14 @@ extern "C" void LLVMRustAddCallSiteAttribute(LLVMValueRef Instr, unsigned Index,
   Call->addAttribute(Index, Attr);
 }
 
+extern "C" void LLVMRustAddCallSiteAttrString(LLVMValueRef Instr, unsigned Index,
+                                              const char *Name) {
+  CallBase *Call = unwrap<CallBase>(Instr);
+  Attribute Attr = Attribute::get(Call->getContext(), Name);
+  Call->addAttribute(Index, Attr);
+}
+
+
 extern "C" void LLVMRustAddAlignmentCallSiteAttr(LLVMValueRef Instr,
                                                  unsigned Index,
                                                  uint32_t Bytes) {