[libc-commits] [llvm] [libc] [openmp] [NVPTX][NFC] Change naming for global objects for ctor / dtor handling (PR #72137)

[Joseph Huber via libc-commits]

https://github.com/jhuber6 created https://github.com/llvm/llvm-project/pull/72137

Summary:
To mimic standard ctor / dtor handling, we emit a bunch of globals for
function pointers that were marked as being a constructor or destructor.
These were previously emitted with `__` syntax. Realistically, we want
symbol names that are not targetable from user code so they cannot
conflict. Normally, this is done with `.`, but NVPTX cannot support
these names. This patch changes it to use `$` which seems to be the
NVPTX equivalent for "This is an internal symbol".


>From 07d514678e4a09ecbca2460d1ba69dd9d6fe6788 Mon Sep 17 00:00:00 2001
From: Joseph Huber <huberjn at outlook.com>
Date: Mon, 13 Nov 2023 11:02:18 -0600
Subject: [PATCH] [NVPTX][NFC] Change naming for global objects for ctor / dtor
 handling

Summary:
To mimic standard ctor / dtor handling, we emit a bunch of globals for
function pointers that were marked as being a constructor or destructor.
These were previously emitted with `__` syntax. Realistically, we want
symbol names that are not targetable from user code so they cannot
conflict. Normally, this is done with `.`, but NVPTX cannot support
these names. This patch changes it to use `$` which seems to be the
NVPTX equivalent for "This is an internal symbol".
---
 libc/utils/gpu/loader/nvptx/Loader.cpp        |  8 ++++----
 llvm/test/CodeGen/NVPTX/lower-ctor-dtor.ll    | 20 +++++++++----------
 .../plugins-nextgen/cuda/src/rtl.cpp          |  6 +++---
 3 files changed, 17 insertions(+), 17 deletions(-)

diff --git a/libc/utils/gpu/loader/nvptx/Loader.cpp b/libc/utils/gpu/loader/nvptx/Loader.cpp
index 5388f287063b7f9..1370fcc60e9790f 100644
--- a/libc/utils/gpu/loader/nvptx/Loader.cpp
+++ b/libc/utils/gpu/loader/nvptx/Loader.cpp
@@ -66,15 +66,15 @@ Expected<void *> get_ctor_dtor_array(const void *image, const size_t size,
       handle_error(toString(name_or_err.takeError()).c_str());
 
     // Search for all symbols that contain a constructor or destructor.
-    if (!name_or_err->starts_with("__init_array_object_") &&
-        !name_or_err->starts_with("__fini_array_object_"))
+    if (!name_or_err->starts_with("$init_array_object$") &&
+        !name_or_err->starts_with("$fini_array_object$"))
       continue;
 
     uint16_t priority;
-    if (name_or_err->rsplit('_').second.getAsInteger(10, priority))
+    if (name_or_err->rsplit('$').second.getAsInteger(10, priority))
       handle_error("Invalid priority for constructor or destructor");
 
-    if (name_or_err->starts_with("__init"))
+    if (name_or_err->starts_with("$init"))
       ctors.emplace_back(std::make_pair(name_or_err->data(), priority));
     else
       dtors.emplace_back(std::make_pair(name_or_err->data(), priority));
diff --git a/llvm/test/CodeGen/NVPTX/lower-ctor-dtor.ll b/llvm/test/CodeGen/NVPTX/lower-ctor-dtor.ll
index f8b3b4b9b8c4467..6e636b9918a4fe7 100644
--- a/llvm/test/CodeGen/NVPTX/lower-ctor-dtor.ll
+++ b/llvm/test/CodeGen/NVPTX/lower-ctor-dtor.ll
@@ -17,23 +17,23 @@
 ; CHECK-NOT: @llvm.global_ctors
 ; CHECK-NOT: @llvm.global_dtors
 
-; CHECK: @__init_array_object_foo_[[HASH:[0-9a-f]+]]_1 = protected addrspace(4) constant ptr @foo, section ".init_array.1"
-; CHECK: @__fini_array_object_bar_[[HASH:[0-9a-f]+]]_1 = protected addrspace(4) constant ptr @bar, section ".fini_array.1"
-; CHECK: @llvm.used = appending global [2 x ptr] [ptr addrspacecast (ptr addrspace(4) @__init_array_object_foo_[[HASH]]_1 to ptr), ptr addrspacecast (ptr addrspace(4) @__fini_array_object_bar_[[HASH]]_1 to ptr)], section "llvm.metadata"
+; CHECK: @"$init_array_object$foo$[[HASH:[0-9a-f]+]]$1" = protected addrspace(4) constant ptr @foo, section ".init_array.1"
+; CHECK: @"$fini_array_object$bar$[[HASH:[0-9a-f]+]]$1" = protected addrspace(4) constant ptr @bar, section ".fini_array.1"
+; CHECK: @llvm.used = appending global [2 x ptr] [ptr addrspacecast (ptr addrspace(4) @"$init_array_object$foo$[[HASH]]$1" to ptr), ptr addrspacecast (ptr addrspace(4) @"$fini_array_object$bar$[[HASH]]$1" to ptr)], section "llvm.metadata"
 ; CHECK: @__fini_array_start = weak protected addrspace(1) global ptr null
 ; CHECK: @__fini_array_end = weak protected addrspace(1) global ptr null
 
-; GLOBAL: @__init_array_object_foo_unique_id_1 = protected addrspace(4) constant ptr @foo, section ".init_array.1"
-; GLOBAL: @__fini_array_object_bar_unique_id_1 = protected addrspace(4) constant ptr @bar, section ".fini_array.1"
-; GLOBAL: @llvm.used = appending global [2 x ptr] [ptr addrspacecast (ptr addrspace(4) @__init_array_object_foo_unique_id_1 to ptr), ptr addrspacecast (ptr addrspace(4) @__fini_array_object_bar_unique_id_1 to ptr)], section "llvm.metadata"
+; GLOBAL: @"$init_array_object$foo$unique_id$1" = protected addrspace(4) constant ptr @foo, section ".init_array.1"
+; GLOBAL: @"$fini_array_object$bar$unique_id$1" = protected addrspace(4) constant ptr @bar, section ".fini_array.1"
+; GLOBAL: @llvm.used = appending global [2 x ptr] [ptr addrspacecast (ptr addrspace(4) @"$init_array_object$foo$unique_id$1" to ptr), ptr addrspacecast (ptr addrspace(4) @"$fini_array_object$bar$unique_id$1" to ptr)], section "llvm.metadata"
 ; GLOBAL: @__fini_array_start = weak protected addrspace(1) global ptr null
 ; GLOBAL: @__fini_array_end = weak protected addrspace(1) global ptr null
 
-; KERNEL: @__init_array_object_foo_[[HASH:[0-9a-f]+]]_1 = protected addrspace(4) constant ptr @foo, section ".init_array.1"
-; KERNEL: @__fini_array_object_bar_[[HASH:[0-9a-f]+]]_1 = protected addrspace(4) constant ptr @bar, section ".fini_array.1"
+; KERNEL: @"$init_array_object$foo$[[HASH:[0-9a-f]+]]$1" = protected addrspace(4) constant ptr @foo, section ".init_array.1"
+; KERNEL: @"$fini_array_object$bar$[[HASH:[0-9a-f]+]]$1" = protected addrspace(4) constant ptr @bar, section ".fini_array.1"
 
-; VISIBILITY: .visible .const .align 8 .u64 __init_array_object_foo_[[HASH:[0-9a-f]+]]_1 = foo;
-; VISIBILITY: .visible .const .align 8 .u64 __fini_array_object_bar_[[HASH:[0-9a-f]+]]_1 = bar;
+; VISIBILITY: .visible .const .align 8 .u64 $init_array_object$foo$[[HASH:[0-9a-f]+]]$1 = foo;
+; VISIBILITY: .visible .const .align 8 .u64 $fini_array_object$bar$[[HASH:[0-9a-f]+]]$1 = bar;
 
 define internal void @foo() {
   ret void
diff --git a/openmp/libomptarget/plugins-nextgen/cuda/src/rtl.cpp b/openmp/libomptarget/plugins-nextgen/cuda/src/rtl.cpp
index a6e28574a7f08e3..1d9425caa1ae45b 100644
--- a/openmp/libomptarget/plugins-nextgen/cuda/src/rtl.cpp
+++ b/openmp/libomptarget/plugins-nextgen/cuda/src/rtl.cpp
@@ -1077,12 +1077,12 @@ struct CUDADeviceTy : public GenericDeviceTy {
       if (!NameOrErr)
         return NameOrErr.takeError();
 
-      if (!NameOrErr->starts_with(IsCtor ? "__init_array_object_"
-                                         : "__fini_array_object_"))
+      if (!NameOrErr->starts_with(IsCtor ? "$init_array_object$"
+                                         : "$fini_array_object$"))
         continue;
 
       uint16_t Priority;
-      if (NameOrErr->rsplit('_').second.getAsInteger(10, Priority))
+      if (NameOrErr->rsplit('$').second.getAsInteger(10, Priority))
         return Plugin::error("Invalid priority for constructor or destructor");
 
       Funcs.emplace_back(*NameOrErr, Priority);