[clang] [llvm] Global constructors/destructors are globals (PR #93914)

via cfe-commits cfe-commits at lists.llvm.org
Thu May 30 19:06:27 PDT 2024


llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang-codegen

Author: Alex Voicu (AlexVlx)

<details>
<summary>Changes</summary>

Currently the payload for global ctors/dtors is passed as an unqualified pointer, which relies on the target being reasonable regarding what AS 0 means, and also is overly conservative. This change correctly places the payload in the target's global AS, and does the same thing for the `global_ctors`/`global_dtors` arrays.

---
Full diff: https://github.com/llvm/llvm-project/pull/93914.diff


9 Files Affected:

- (modified) clang/lib/CodeGen/CodeGenModule.cpp (+6-5) 
- (modified) clang/test/CodeGen/asan-constructor.c (+2) 
- (modified) clang/test/CodeGen/attr-retain.c (-1) 
- (modified) clang/test/CodeGenCUDA/llvm-used.cu (+1-1) 
- (modified) clang/test/CodeGenCXX/cxx0x-initializer-stdinitializerlist.cpp (+2-1) 
- (modified) clang/test/CodeGenCXX/static-member-variable-explicit-specialization.cpp (+5-1) 
- (modified) clang/test/OpenMP/amdgcn_target_global_constructor.cpp (+2-2) 
- (modified) llvm/lib/Transforms/Utils/ModuleUtils.cpp (+6-7) 
- (modified) llvm/test/tools/llvm-reduce/remove-ifunc-program-addrspace.ll (+2-2) 


``````````diff
diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index c2314c3a57d33..b59c5c52783e9 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -2047,9 +2047,9 @@ void CodeGenModule::EmitCtorList(CtorList &Fns, const char *GlobalName) {
   llvm::Type *CtorPFTy = llvm::PointerType::get(CtorFTy,
       TheModule.getDataLayout().getProgramAddressSpace());
 
-  // Get the type of a ctor entry, { i32, void ()*, i8* }.
-  llvm::StructType *CtorStructTy = llvm::StructType::get(
-      Int32Ty, CtorPFTy, VoidPtrTy);
+  // Get the type of a ctor entry, { i32, program void ()*, global i8* }.
+  llvm::StructType *CtorStructTy =
+      llvm::StructType::get(Int32Ty, CtorPFTy, GlobalsInt8PtrTy);
 
   // Construct the constructor and destructor arrays.
   ConstantInitBuilder builder(*this);
@@ -2061,14 +2061,15 @@ void CodeGenModule::EmitCtorList(CtorList &Fns, const char *GlobalName) {
     if (I.AssociatedData)
       ctor.add(I.AssociatedData);
     else
-      ctor.addNullPointer(VoidPtrTy);
+      ctor.addNullPointer(GlobalsInt8PtrTy);
     ctor.finishAndAddTo(ctors);
   }
 
   auto list =
     ctors.finishAndCreateGlobal(GlobalName, getPointerAlign(),
                                 /*constant*/ false,
-                                llvm::GlobalValue::AppendingLinkage);
+                                llvm::GlobalValue::AppendingLinkage,
+                                GlobalsInt8PtrTy->getAddressSpace());
 
   // The LTO linker doesn't seem to like it when we set an alignment
   // on appending variables.  Take it off as a workaround.
diff --git a/clang/test/CodeGen/asan-constructor.c b/clang/test/CodeGen/asan-constructor.c
index 762bf0778565d..41212d45a5c63 100644
--- a/clang/test/CodeGen/asan-constructor.c
+++ b/clang/test/CodeGen/asan-constructor.c
@@ -1,5 +1,7 @@
 // RUN: %clang_cc1 -fsanitize=address -emit-llvm -o - %s | FileCheck %s
 // RUN: %clang_cc1 -triple wasm32-unknown-emscripten -fsanitize=address -emit-llvm -o - %s | FileCheck %s --check-prefix=EMSCRIPTEN
+// RUN: %clang_cc1 -triple amdgcn-amd-amdhsa -fsanitize=address -emit-llvm -o - %s | FileCheck %s --check-prefix=GLOBALAS
 
 // CHECK: @llvm.global_ctors = appending global [1 x { i32, ptr, ptr }] [{ i32, ptr, ptr } { i32 1, ptr @asan.module_ctor, ptr null }]
 // EMSCRIPTEN: @llvm.global_ctors = appending global [1 x { i32, ptr, ptr }] [{ i32, ptr, ptr } { i32 50, ptr @asan.module_ctor, ptr null }]
+// GLOBALAS: @llvm.global_ctors = appending addrspace(1) global [1 x { i32, ptr, ptr addrspace(1) }] [{ i32, ptr, ptr addrspace(1) } { i32 1, ptr @asan.module_ctor, ptr addrspace(1) null }]
diff --git a/clang/test/CodeGen/attr-retain.c b/clang/test/CodeGen/attr-retain.c
index fc41be76f9d0a..6a9869c00392d 100644
--- a/clang/test/CodeGen/attr-retain.c
+++ b/clang/test/CodeGen/attr-retain.c
@@ -11,7 +11,6 @@
 
 // CHECK:      @llvm.used = appending global [8 x ptr] [ptr @c0, ptr @foo.l0, ptr @f0, ptr @f2, ptr @g0, ptr @g1, ptr @g3, ptr @g4], section "llvm.metadata"
 // CHECK:      @llvm.compiler.used = appending global [3 x ptr] [ptr @f2, ptr @g3, ptr @g4], section "llvm.metadata"
-
 const int c0 __attribute__((retain)) = 42;
 
 void foo(void) {
diff --git a/clang/test/CodeGenCUDA/llvm-used.cu b/clang/test/CodeGenCUDA/llvm-used.cu
index c39111dd48036..9f22dabde3c2d 100644
--- a/clang/test/CodeGenCUDA/llvm-used.cu
+++ b/clang/test/CodeGenCUDA/llvm-used.cu
@@ -1,7 +1,7 @@
 // RUN: %clang_cc1 -emit-llvm %s -o - -fcuda-is-device -triple nvptx64-unknown-unknown | FileCheck %s
 
 
-// Make sure we emit the proper addrspacecast for llvm.used.  PR22383 exposed an
+// Make sure we emit the proper addrspacecast for llvm.used. PR22383 exposed an
 // issue where we were generating a bitcast instead of an addrspacecast.
 
 // CHECK: @llvm.compiler.used = appending global [1 x ptr] [ptr addrspacecast (ptr addrspace(1) @a to ptr)], section "llvm.metadata"
diff --git a/clang/test/CodeGenCXX/cxx0x-initializer-stdinitializerlist.cpp b/clang/test/CodeGenCXX/cxx0x-initializer-stdinitializerlist.cpp
index aa2f078a5fb0c..2e22192e8b388 100644
--- a/clang/test/CodeGenCXX/cxx0x-initializer-stdinitializerlist.cpp
+++ b/clang/test/CodeGenCXX/cxx0x-initializer-stdinitializerlist.cpp
@@ -90,7 +90,8 @@ std::initializer_list<int> thread_local x = {1, 2, 3, 4};
 // AMDGCN: @[[REFTMP1:.*]] = private addrspace(4) constant [2 x i32] [i32 42, i32 43], align 4
 // AMDGCN: @[[REFTMP2:.*]] = private addrspace(4) constant [3 x %{{.*}}] [%{{.*}} { i32 1 }, %{{.*}} { i32 2 }, %{{.*}} { i32 3 }], align 4
 
-// CHECK: appending global
+// X86: appending global
+// AMDGCN: appending addrspace(1) global
 
 // thread_local initializer:
 // X86-LABEL: define internal void @__cxx_global_var_init
diff --git a/clang/test/CodeGenCXX/static-member-variable-explicit-specialization.cpp b/clang/test/CodeGenCXX/static-member-variable-explicit-specialization.cpp
index 46c4c4d391769..58055130cd708 100644
--- a/clang/test/CodeGenCXX/static-member-variable-explicit-specialization.cpp
+++ b/clang/test/CodeGenCXX/static-member-variable-explicit-specialization.cpp
@@ -1,6 +1,8 @@
 // RUN: %clang_cc1 %s -std=c++1y -triple=x86_64-pc-linux -emit-llvm -o - | FileCheck --check-prefix=ELF --check-prefix=ALL %s
 // RUN: %clang_cc1 %s -std=c++1y -triple=x86_64-apple-darwin -emit-llvm -o - | FileCheck --check-prefix=MACHO --check-prefix=ALL %s
 // RUN: %clang_cc1 %s -std=c++1y -triple=x86_64-pc-linux -emit-llvm -fdeclspec -DSELECTANY -o - | FileCheck --check-prefix=ELF-SELECTANY %s
+// RUN: %clang_cc1 %s -std=c++1y -triple=amdgcn-amd-amdhsa -emit-llvm -o - | FileCheck --check-prefix=GLOBALAS-ELF %s
+// RUN: %clang_cc1 %s -std=c++1y -triple=amdgcn-amd-amdhsa -emit-llvm -fdeclspec -DSELECTANY -o - | FileCheck --check-prefix=GLOBALAS-ELF-SELECTANY %s
 
 #ifdef SELECTANY
 struct S {
@@ -12,6 +14,7 @@ int f();
 
 // ELF-SELECTANY: @llvm.global_ctors = appending global [1 x { i32, ptr, ptr }] [{ i32, ptr, ptr } { i32 65535, ptr @__cxx_global_var_init, ptr @selectany }]
 // ELF-SELECTANY: @llvm.used = appending global [1 x ptr] [ptr @selectany]
+// GLOBALAS-ELF-SELECTANY: @llvm.global_ctors = appending addrspace(1) global [1 x { i32, ptr, ptr addrspace(1) }] [{ i32, ptr, ptr addrspace(1) } { i32 65535, ptr @__cxx_global_var_init, ptr addrspace(1) @selectany }]
 int __declspec(selectany) selectany = f();
 
 #else
@@ -30,6 +33,7 @@ template<> int A<char>::a;
 template<> int A<bool>::a = 10;
 
 // ALL: @llvm.global_ctors = appending global [16 x { i32, ptr, ptr }]
+// GLOBALAS-ELF: @llvm.global_ctors = appending addrspace(1) global [16 x { i32, ptr, ptr addrspace(1) }]
 
 // ELF:  [{ i32, ptr, ptr } { i32 65535, ptr @[[unordered:[^,]*]], ptr @_ZN1AIsE1aE },
 // MACHO: [{ i32, ptr, ptr } { i32 65535, ptr @[[unordered:[^,]*]], ptr null },
@@ -73,7 +77,7 @@ template<> int A<bool>::a = 10;
 // MACHO: { i32, ptr, ptr } { i32 65535, ptr @[[unordered22:[^,]*]], ptr null },
 
 // ELF:  { i32, ptr, ptr } { i32 65535, ptr @[[unordered21:[^,]*]], ptr @_ZN4Fib2ILi5EE1aE },
-// MACHO: { i32, ptr, ptr } { i32 65535, ptr @[[unordered21:[^,]*]], ptr null }, 
+// MACHO: { i32, ptr, ptr } { i32 65535, ptr @[[unordered21:[^,]*]], ptr null },
 
 // ALL:  { i32, ptr, ptr } { i32 65535, ptr @_GLOBAL__sub_I_static_member_variable_explicit_specialization.cpp, ptr null }]
 
diff --git a/clang/test/OpenMP/amdgcn_target_global_constructor.cpp b/clang/test/OpenMP/amdgcn_target_global_constructor.cpp
index 80a5067b357a2..fe414b59588c0 100644
--- a/clang/test/OpenMP/amdgcn_target_global_constructor.cpp
+++ b/clang/test/OpenMP/amdgcn_target_global_constructor.cpp
@@ -21,8 +21,8 @@ S A;
 
 #endif
 //.
-// CHECK: @llvm.global_ctors = appending global [1 x { i32, ptr, ptr }] [{ i32, ptr, ptr } { i32 65535, ptr @_GLOBAL__sub_I_amdgcn_target_global_constructor.cpp, ptr null }]
-// CHECK: @llvm.global_dtors = appending global [1 x { i32, ptr, ptr }] [{ i32, ptr, ptr } { i32 65535, ptr @__dtor_A, ptr null }]
+// CHECK: @llvm.global_ctors = appending addrspace(1) global [1 x { i32, ptr, ptr addrspace(1) }] [{ i32, ptr, ptr addrspace(1) } { i32 65535, ptr @_GLOBAL__sub_I_amdgcn_target_global_constructor.cpp, ptr addrspace(1) null }]
+// CHECK: @llvm.global_dtors = appending addrspace(1) global [1 x { i32, ptr, ptr addrspace(1) }] [{ i32, ptr, ptr addrspace(1) } { i32 65535, ptr @__dtor_A, ptr addrspace(1) null }]
 //.
 // CHECK-LABEL: define {{[^@]+}}@__cxx_global_var_init
 // CHECK-SAME: () #[[ATTR0:[0-9]+]] {
diff --git a/llvm/lib/Transforms/Utils/ModuleUtils.cpp b/llvm/lib/Transforms/Utils/ModuleUtils.cpp
index 122279160cc7e..7151cc869bc95 100644
--- a/llvm/lib/Transforms/Utils/ModuleUtils.cpp
+++ b/llvm/lib/Transforms/Utils/ModuleUtils.cpp
@@ -30,6 +30,8 @@ static void appendToGlobalArray(StringRef ArrayName, Module &M, Function *F,
                                 int Priority, Constant *Data) {
   IRBuilder<> IRB(M.getContext());
   FunctionType *FnTy = FunctionType::get(IRB.getVoidTy(), false);
+  PointerType *GlobalsInt8PtrTy = PointerType::get(
+      M.getContext(), M.getDataLayout().getDefaultGlobalsAddressSpace());
 
   // Get the current set of static global constructors and add the new ctor
   // to the list.
@@ -47,15 +49,15 @@ static void appendToGlobalArray(StringRef ArrayName, Module &M, Function *F,
   } else {
     EltTy = StructType::get(IRB.getInt32Ty(),
                             PointerType::get(FnTy, F->getAddressSpace()),
-                            IRB.getPtrTy());
+                            GlobalsInt8PtrTy);
   }
 
   // Build a 3 field global_ctor entry.  We don't take a comdat key.
   Constant *CSVals[3];
   CSVals[0] = IRB.getInt32(Priority);
   CSVals[1] = F;
-  CSVals[2] = Data ? ConstantExpr::getPointerCast(Data, IRB.getPtrTy())
-                   : Constant::getNullValue(IRB.getPtrTy());
+  CSVals[2] = Data ? ConstantExpr::getPointerCast(Data, GlobalsInt8PtrTy)
+                   : Constant::getNullValue(GlobalsInt8PtrTy);
   Constant *RuntimeCtorInit =
       ConstantStruct::get(EltTy, ArrayRef(CSVals, EltTy->getNumElements()));
 
@@ -437,12 +439,9 @@ bool llvm::lowerGlobalIFuncUsersAsGlobalCtor(
 
   InitBuilder.CreateRetVoid();
 
-  PointerType *ConstantDataTy = PointerType::get(Ctx, 0);
-
   // TODO: Is this the right priority? Probably should be before any other
   // constructors?
   const int Priority = 10;
-  appendToGlobalCtors(M, NewCtor, Priority,
-                      ConstantPointerNull::get(ConstantDataTy));
+  appendToGlobalCtors(M, NewCtor, Priority, nullptr);
   return UnhandledUsers;
 }
diff --git a/llvm/test/tools/llvm-reduce/remove-ifunc-program-addrspace.ll b/llvm/test/tools/llvm-reduce/remove-ifunc-program-addrspace.ll
index e275d61764b21..7ddab0b6a815e 100644
--- a/llvm/test/tools/llvm-reduce/remove-ifunc-program-addrspace.ll
+++ b/llvm/test/tools/llvm-reduce/remove-ifunc-program-addrspace.ll
@@ -15,8 +15,8 @@ define void @existing_ctor() addrspace(1) {
 
 ; CHECK-FINAL: [[TABLE:@[0-9]+]] = internal addrspace(2) global [6 x ptr addrspace(1)] poison, align 8
 
-; CHECK-FINAL: @llvm.global_ctors = appending addrspace(2) global [2 x { i32, ptr addrspace(1), ptr }] [{ i32, ptr addrspace(1), ptr } { i32 0, ptr addrspace(1) @existing_ctor, ptr null }, { i32, ptr addrspace(1), ptr } { i32 10, ptr addrspace(1) [[TABLE_CTOR:@[0-9]+]], ptr null }]
- at llvm.global_ctors = appending global [1 x { i32, ptr addrspace(1), ptr }] [{ i32, ptr addrspace(1), ptr } { i32 0, ptr addrspace(1) @existing_ctor, ptr null }]
+; CHECK-FINAL: @llvm.global_ctors = appending addrspace(2) global [2 x { i32, ptr addrspace(1), ptr addrspace(2) }] [{ i32, ptr addrspace(1), ptr addrspace(2) } { i32 0, ptr addrspace(1) @existing_ctor, ptr addrspace(2) null }, { i32, ptr addrspace(1), ptr addrspace(2) } { i32 10, ptr addrspace(1) [[TABLE_CTOR:@[0-9]+]], ptr addrspace(2) null }]
+ at llvm.global_ctors = appending global [1 x { i32, ptr addrspace(1), ptr addrspace(2) }] [{ i32, ptr addrspace(1), ptr addrspace(2) } { i32 0, ptr addrspace(1) @existing_ctor, ptr addrspace(2) null }]
 
 
 

``````````

</details>


https://github.com/llvm/llvm-project/pull/93914


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