zequanwu created this revision.
zequanwu added reviewers: pcc, aaron.ballman, rnk, rsmith.
Herald added subscribers: dexonsmith, jdoerfert, hiraditya.
zequanwu requested review of this revision.
Herald added projects: clang, LLVM.
Herald added subscribers: llvm-commits, cfe-commits.
Functions or variables with this attribute will not have
local_unnamed_addr/unnamed_addr in IR. So, they will show up in
address-significant table.
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D98295
Files:
clang/include/clang/Basic/Attr.td
clang/include/clang/Basic/AttrDocs.td
clang/lib/CodeGen/CodeGenModule.cpp
clang/test/CodeGenCXX/attr-addrsig.cpp
clang/test/Misc/pragma-attribute-supported-attributes-list.test
clang/test/Sema/attr-addrsig.c
llvm/include/llvm/IR/GlobalValue.h
llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
llvm/lib/IR/AsmWriter.cpp
llvm/lib/IR/Core.cpp
llvm/lib/Transforms/IPO/GlobalOpt.cpp
Index: llvm/lib/Transforms/IPO/GlobalOpt.cpp
===================================================================
--- llvm/lib/Transforms/IPO/GlobalOpt.cpp
+++ llvm/lib/Transforms/IPO/GlobalOpt.cpp
@@ -2107,9 +2107,11 @@
return false;
bool Changed = false;
- if (!GS.IsCompared && !GV.hasGlobalUnnamedAddr()) {
- auto NewUnnamedAddr = GV.hasLocalLinkage() ? GlobalValue::UnnamedAddr::Global
- : GlobalValue::UnnamedAddr::Local;
+ if (!GS.IsCompared && !GV.hasGlobalUnnamedAddr() &&
+ GV.getUnnamedAddr() != GlobalValue::UnnamedAddr::Addrsig) {
+ auto NewUnnamedAddr = GV.hasLocalLinkage()
+ ? GlobalValue::UnnamedAddr::Global
+ : GlobalValue::UnnamedAddr::Local;
if (NewUnnamedAddr != GV.getUnnamedAddr()) {
GV.setUnnamedAddr(NewUnnamedAddr);
NumUnnamed++;
Index: llvm/lib/IR/Core.cpp
===================================================================
--- llvm/lib/IR/Core.cpp
+++ llvm/lib/IR/Core.cpp
@@ -1991,6 +1991,7 @@
LLVMUnnamedAddr LLVMGetUnnamedAddress(LLVMValueRef Global) {
switch (unwrap<GlobalValue>(Global)->getUnnamedAddr()) {
+ case GlobalVariable::UnnamedAddr::Addrsig:
case GlobalVariable::UnnamedAddr::None:
return LLVMNoUnnamedAddr;
case GlobalVariable::UnnamedAddr::Local:
Index: llvm/lib/IR/AsmWriter.cpp
===================================================================
--- llvm/lib/IR/AsmWriter.cpp
+++ llvm/lib/IR/AsmWriter.cpp
@@ -3487,6 +3487,7 @@
static StringRef getUnnamedAddrEncoding(GlobalVariable::UnnamedAddr UA) {
switch (UA) {
+ case GlobalVariable::UnnamedAddr::Addrsig:
case GlobalVariable::UnnamedAddr::None:
return "";
case GlobalVariable::UnnamedAddr::Local:
Index: llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
===================================================================
--- llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -1117,6 +1117,7 @@
static unsigned getEncodedUnnamedAddr(const GlobalValue &GV) {
switch (GV.getUnnamedAddr()) {
+ case GlobalValue::UnnamedAddr::Addrsig:
case GlobalValue::UnnamedAddr::None: return 0;
case GlobalValue::UnnamedAddr::Local: return 2;
case GlobalValue::UnnamedAddr::Global: return 1;
Index: llvm/include/llvm/IR/GlobalValue.h
===================================================================
--- llvm/include/llvm/IR/GlobalValue.h
+++ llvm/include/llvm/IR/GlobalValue.h
@@ -188,6 +188,7 @@
unsigned getAddressSpace() const;
enum class UnnamedAddr {
+ Addrsig,
None,
Local,
Global,
@@ -203,7 +204,8 @@
/// table. It should probably not be used in optimizations, as the value may
/// have uses outside the module; use hasGlobalUnnamedAddr() instead.
bool hasAtLeastLocalUnnamedAddr() const {
- return getUnnamedAddr() != UnnamedAddr::None;
+ return getUnnamedAddr() != UnnamedAddr::Addrsig &&
+ getUnnamedAddr() != UnnamedAddr::None;
}
UnnamedAddr getUnnamedAddr() const {
@@ -212,6 +214,8 @@
void setUnnamedAddr(UnnamedAddr Val) { UnnamedAddrVal = unsigned(Val); }
static UnnamedAddr getMinUnnamedAddr(UnnamedAddr A, UnnamedAddr B) {
+ if (A == UnnamedAddr::Addrsig || B == UnnamedAddr::Addrsig)
+ return UnnamedAddr::Addrsig;
if (A == UnnamedAddr::None || B == UnnamedAddr::None)
return UnnamedAddr::None;
if (A == UnnamedAddr::Local || B == UnnamedAddr::Local)
Index: clang/test/Sema/attr-addrsig.c
===================================================================
--- /dev/null
+++ clang/test/Sema/attr-addrsig.c
@@ -0,0 +1,8 @@
+// RUN: %clang_cc1 -verify -fsyntax-only %s
+
+__attribute__((addrsig)) int i;
+
+__attribute__((addrsig)) void f();
+__attribute__((addrsig)) void g() {}
+
+struct __attribute__((addrsig)) A {}; // expected-warning {{'addrsig' attribute only applies to functions and variables}}
Index: clang/test/Misc/pragma-attribute-supported-attributes-list.test
===================================================================
--- clang/test/Misc/pragma-attribute-supported-attributes-list.test
+++ clang/test/Misc/pragma-attribute-supported-attributes-list.test
@@ -10,6 +10,7 @@
// CHECK-NEXT: AVRSignal (SubjectMatchRule_function)
// CHECK-NEXT: AbiTag (SubjectMatchRule_record_not_is_union, SubjectMatchRule_variable, SubjectMatchRule_function, SubjectMatchRule_namespace)
// CHECK-NEXT: AcquireHandle (SubjectMatchRule_function, SubjectMatchRule_type_alias, SubjectMatchRule_variable_is_parameter)
+// CHECK-NEXT: Addrsig (SubjectMatchRule_function, SubjectMatchRule_variable)
// CHECK-NEXT: Alias (SubjectMatchRule_function, SubjectMatchRule_variable_is_global)
// CHECK-NEXT: AlignValue (SubjectMatchRule_variable, SubjectMatchRule_type_alias)
// CHECK-NEXT: AllocSize (SubjectMatchRule_function)
Index: clang/test/CodeGenCXX/attr-addrsig.cpp
===================================================================
--- /dev/null
+++ clang/test/CodeGenCXX/attr-addrsig.cpp
@@ -0,0 +1,61 @@
+// RUN: %clang_cc1 -S -emit-llvm %s -triple x86_64-unknown-linux-gnu -O2 -o - | FileCheck %s
+
+// CHECK: @i1 = {{.*}}unnamed_addr
+// CHECK-NEXT: @i2 = {{.*}}unnamed_addr
+int i1;
+int i2 = 0;
+
+// CHECK-NOT: @i3 = {{.*}}unnamed_addr
+// CHECK-NOT: @i4 = {{.*}}unnamed_addr
+[[clang::addrsig]] int i3;
+[[clang::addrsig]] int i4 = 0;
+
+// CHECK-DAG: declare void @_Z2f1i{{.*}}unnamed_addr
+void f1(int i);
+// CHECK-DAG: define dso_local i32 @_Z2f2i{{.*}}unnamed_addr
+int f2(int i) {
+ f1(i);
+ return i * 2;
+}
+
+// CHECK-NOT: @_Z3f1v{{.*}}unnamed_addr
+[[clang::addrsig]] void f3(int i);
+void f3(int i);
+// CHECK-NOT: @_Z4f1v{{.*}}unnamed_addr
+[[clang::addrsig]] int f4(int i) {
+ f3(i);
+ return i * 2;
+}
+
+
+// CHECK-DAG: declare void @_ZN1AC1Ev{{.*}}unnamed_addr
+// CHECK-DAG: declare void @_ZN1AD1Ev{{.*}}unnamed_addr
+// CHECK-DAG: declare void @_ZN1A2f1Ev{{.*}}unnamed_addr
+// CHECK-DAG: declare void @_ZN1A2f2Ev{{.*}}unnamed_addr
+
+// CHECK-DAG: declare void @_ZN1BC1Ev({{.*}}) #1
+// CHECK-DAG: declare void @_ZN1BD1Ev({{.*}}) #3
+// CHECK-DAG: declare void @_ZN1B2f1Ev({{.*}}) #1
+// CHECK-DAG: declare void @_ZN1B2f2Ev({{.*}}) #1
+struct A {
+ A();
+ ~A();
+ void f1();
+ virtual void f2();
+};
+
+struct B {
+ [[clang::addrsig]] B();
+ [[clang::addrsig]] ~B();
+ [[clang::addrsig]] void f1();
+ [[clang::addrsig]] virtual void f2();
+};
+
+void test() {
+ A a;
+ B b;
+ a.f1();
+ a.f2();
+ b.f1();
+ b.f2();
+}
Index: clang/lib/CodeGen/CodeGenModule.cpp
===================================================================
--- clang/lib/CodeGen/CodeGenModule.cpp
+++ clang/lib/CodeGen/CodeGenModule.cpp
@@ -2054,6 +2054,9 @@
if (MD->isVirtual())
F->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
+ if (FD->hasAttr<AddrsigAttr>())
+ F->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Addrsig);
+
// Don't emit entries for function declarations in the cross-DSO mode. This
// is handled with better precision by the receiving DSO. But if jump tables
// are non-canonical then we need type metadata in order to produce the local
@@ -4294,6 +4297,9 @@
if (D->hasAttr<AnnotateAttr>())
AddGlobalAnnotations(D, GV);
+ if (D->hasAttr<AddrsigAttr>())
+ GV->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Addrsig);
+
// Set the llvm linkage type as appropriate.
llvm::GlobalValue::LinkageTypes Linkage =
getLLVMLinkageVarDefinition(D, GV->isConstant());
Index: clang/include/clang/Basic/AttrDocs.td
===================================================================
--- clang/include/clang/Basic/AttrDocs.td
+++ clang/include/clang/Basic/AttrDocs.td
@@ -443,6 +443,18 @@
}];
}
+def AddrsigDocs : Documentation {
+ let Category = DocCatFunction;
+ let Content = [{
+Functions or variables attached with ``addrsig`` will be put into the
+address-significant table, which disables identical code folding (ICF) on
+setions in it (only useful when linking with lld). For the COFF port of lld, the
+default icf (``/OPT:safeicf``) will fold code sections regardless the existance
+of address-significant table. So, ``/OPT:safeicf`` is needed if you don't want
+code sections folding when they are in the table.
+ }];
+}
+
def AssertCapabilityDocs : Documentation {
let Category = DocCatFunction;
let Heading = "assert_capability, assert_shared_capability";
Index: clang/include/clang/Basic/Attr.td
===================================================================
--- clang/include/clang/Basic/Attr.td
+++ clang/include/clang/Basic/Attr.td
@@ -1345,6 +1345,13 @@
let SimpleHandler = 1;
}
+def Addrsig : InheritableAttr {
+ let Spellings = [Clang<"addrsig">];
+ let Documentation = [AddrsigDocs];
+ let Subjects = SubjectList<[Function, Var]>;
+ let SimpleHandler = 1;
+}
+
def FastCall : DeclOrTypeAttr {
let Spellings = [GCC<"fastcall">, Keyword<"__fastcall">,
Keyword<"_fastcall">];
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