[clang] 932ca85 - libclc: remove __attribute__((assume)) for clspv targets (#92126)

[via cfe-commits]

Author: Romaric Jodin
Date: 2024-05-17T06:13:32-07:00
New Revision: 932ca85680db5e4579306f37e55746097fb8ec7f

URL: https://github.com/llvm/llvm-project/commit/932ca85680db5e4579306f37e55746097fb8ec7f
DIFF: https://github.com/llvm/llvm-project/commit/932ca85680db5e4579306f37e55746097fb8ec7f.diff

LOG: libclc: remove __attribute__((assume)) for clspv targets (#92126)

Instead add a proper attribute in clang, and add convert it to function
metadata to keep the information in the IR. The goal is to remove the
dependency on __attribute__((assume)) that should have not be there in
the first place.

Ref https://github.com/llvm/llvm-project/pull/84934

Added: 
    clang/test/CodeGen/clspv_libclc_builtin.c

Modified: 
    clang/docs/ReleaseNotes.rst
    clang/include/clang/Basic/Attr.td
    clang/include/clang/Basic/AttrDocs.td
    clang/lib/CodeGen/CodeGenFunction.cpp
    clang/test/Misc/pragma-attribute-supported-attributes-list.test
    libclc/generic/include/clc/clcfunc.h

Removed: 
    


################################################################################
diff  --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 40e41c940b6af..9799f878d7d72 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -403,6 +403,10 @@ Attribute Changes in Clang
 - Clang now warns that the ``exclude_from_explicit_instantiation`` attribute
   is ignored when applied to a local class or a member thereof.
 
+- The ``clspv_libclc_builtin`` attribute has been added to allow clspv
+  (`OpenCL-C to Vulkan SPIR-V compiler <https://github.com/google/clspv>`_) to identify functions coming from libclc
+  (`OpenCL-C builtin library <https://libclc.llvm.org>`_).
+
 Improvements to Clang's diagnostics
 -----------------------------------
 - Clang now applies syntax highlighting to the code snippets it

diff  --git a/clang/include/clang/Basic/Attr.td b/clang/include/clang/Basic/Attr.td
index 52552ba488560..38ee8356583be 100644
--- a/clang/include/clang/Basic/Attr.td
+++ b/clang/include/clang/Basic/Attr.td
@@ -4561,3 +4561,10 @@ def CodeAlign: StmtAttr {
     static constexpr int MaximumAlignment = 4096;
   }];
 }
+
+def ClspvLibclcBuiltin: InheritableAttr {
+  let Spellings = [Clang<"clspv_libclc_builtin">];
+  let Subjects = SubjectList<[Function]>;
+  let Documentation = [ClspvLibclcBuiltinDoc];
+  let SimpleHandler = 1;
+}

diff  --git a/clang/include/clang/Basic/AttrDocs.td b/clang/include/clang/Basic/AttrDocs.td
index f351822ac74bd..b48aaf65558ac 100644
--- a/clang/include/clang/Basic/AttrDocs.td
+++ b/clang/include/clang/Basic/AttrDocs.td
@@ -8087,3 +8087,17 @@ requirement:
   }
   }];
 }
+
+def ClspvLibclcBuiltinDoc : Documentation {
+  let Category = DocCatFunction;
+  let Content = [{
+Attribute used by `clspv`_ (OpenCL-C to Vulkan SPIR-V compiler) to identify functions coming from `libclc`_ (OpenCL-C builtin library).
+
+.. code-block:: c
+
+  void __attribute__((clspv_libclc_builtin)) libclc_builtin() {}
+
+.. _`clspv`: https://github.com/google/clspv
+.. _`libclc`: https://libclc.llvm.org
+}];
+}

diff  --git a/clang/lib/CodeGen/CodeGenFunction.cpp b/clang/lib/CodeGen/CodeGenFunction.cpp
index 34dc0bd5c15bc..04abdadd95379 100644
--- a/clang/lib/CodeGen/CodeGenFunction.cpp
+++ b/clang/lib/CodeGen/CodeGenFunction.cpp
@@ -985,6 +985,11 @@ void CodeGenFunction::StartFunction(GlobalDecl GD, QualType RetTy,
     EmitKernelMetadata(FD, Fn);
   }
 
+  if (FD && FD->hasAttr<ClspvLibclcBuiltinAttr>()) {
+    Fn->setMetadata("clspv_libclc_builtin",
+                    llvm::MDNode::get(getLLVMContext(), {}));
+  }
+
   // If we are checking function types, emit a function type signature as
   // prologue data.
   if (FD && SanOpts.has(SanitizerKind::Function)) {

diff  --git a/clang/test/CodeGen/clspv_libclc_builtin.c b/clang/test/CodeGen/clspv_libclc_builtin.c
new file mode 100644
index 0000000000000..ada2555c79e5b
--- /dev/null
+++ b/clang/test/CodeGen/clspv_libclc_builtin.c
@@ -0,0 +1,6 @@
+// RUN: %clang_cc1 -triple spir -emit-llvm %s -o - | FileCheck %s
+
+// CHECK: @foo()
+// CHECK-SAME: !clspv_libclc_builtin
+
+void __attribute__((clspv_libclc_builtin)) foo() {}

diff  --git a/clang/test/Misc/pragma-attribute-supported-attributes-list.test b/clang/test/Misc/pragma-attribute-supported-attributes-list.test
index 318bfb2df2a7a..fd0e6d71baa80 100644
--- a/clang/test/Misc/pragma-attribute-supported-attributes-list.test
+++ b/clang/test/Misc/pragma-attribute-supported-attributes-list.test
@@ -48,6 +48,7 @@
 // CHECK-NEXT: Capability (SubjectMatchRule_record, SubjectMatchRule_type_alias)
 // CHECK-NEXT: CarriesDependency (SubjectMatchRule_variable_is_parameter, SubjectMatchRule_objc_method, SubjectMatchRule_function)
 // CHECK-NEXT: Cleanup (SubjectMatchRule_variable_is_local)
+// CHECK-NEXT: ClspvLibclcBuiltin (SubjectMatchRule_function)
 // CHECK-NEXT: CmseNSEntry (SubjectMatchRule_function)
 // CHECK-NEXT: Cold (SubjectMatchRule_function)
 // CHECK-NEXT: Common (SubjectMatchRule_variable)

diff  --git a/libclc/generic/include/clc/clcfunc.h b/libclc/generic/include/clc/clcfunc.h
index ad9eb23f29333..086d780b97085 100644
--- a/libclc/generic/include/clc/clcfunc.h
+++ b/libclc/generic/include/clc/clcfunc.h
@@ -7,8 +7,7 @@
 #if defined(CLC_SPIRV) || defined(CLC_SPIRV64)
 #define _CLC_DEF
 #elif defined(CLC_CLSPV) || defined(CLC_CLSPV64)
-#define _CLC_DEF                                                               \
-  __attribute__((noinline)) __attribute__((assume("clspv_libclc_builtin")))
+#define _CLC_DEF __attribute__((noinline)) __attribute__((clspv_libclc_builtin))
 #else
 #define _CLC_DEF __attribute__((always_inline))
 #endif