First step in fixing PR8927:
Add a unnamed_addr bit to global variables and functions. This will be used
to indicate that the address is not significant and therefore the constant
or function can be merged with others.
If an optimization pass can show that an address is not used, it can set this.
Examples of things that can have this set by the FE are globals created to
hold string literals and C++ constructors.
Adding unnamed_addr to a non-const global should have no effect unless
an optimization can transform that global into a constant.
Aliases are not allowed to have unnamed_addr since I couldn't figure
out any use for it.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123063 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/docs/BitCodeFormat.html b/docs/BitCodeFormat.html
index d8ddc2b..0b8747c 100644
--- a/docs/BitCodeFormat.html
+++ b/docs/BitCodeFormat.html
@@ -922,6 +922,9 @@
<li><i>threadlocal</i>: If present and non-zero, indicates that the variable
is <tt>thread_local</tt></li>
+<li><i>unnamed_addr</i>: If present and non-zero, indicates that the variable
+has <tt>unnamed_addr<tt></li>
+
</ul>
</div>
@@ -975,6 +978,10 @@
<li><i>gc</i>: If present and nonzero, the 1-based garbage collector
index in the table of
<a href="#MODULE_CODE_GCNAME">MODULE_CODE_GCNAME</a> entries.</li>
+
+<li><i>unnamed_addr</i>: If present and non-zero, indicates that the function
+has <tt>unnamed_addr<tt></li>
+
</ul>
</div>
diff --git a/docs/LangRef.html b/docs/LangRef.html
index 2114412..2121fc6 100644
--- a/docs/LangRef.html
+++ b/docs/LangRef.html
@@ -846,6 +846,10 @@
region of memory, and all memory objects in LLVM are accessed through
pointers.</p>
+<p>Global variables can be marked with <tt>unnamed_addr</tt> which indicates
+ that the address is not significant, only the content. Constants marked
+ like this can be merged if they have the same content.</p>
+
<p>A global variable may be declared to reside in a target-specific numbered
address space. For targets that support them, address spaces may affect how
optimizations are performed and/or what target instructions are used to
@@ -885,7 +889,8 @@
<p>LLVM function definitions consist of the "<tt>define</tt>" keyword, an
optional <a href="#linkage">linkage type</a>, an optional
<a href="#visibility">visibility style</a>, an optional
- <a href="#callingconv">calling convention</a>, a return type, an optional
+ <a href="#callingconv">calling convention</a>,
+ an optional <tt>unnamed_addr</tt> attribute, a return type, an optional
<a href="#paramattrs">parameter attribute</a> for the return type, a function
name, a (possibly empty) argument list (each with optional
<a href="#paramattrs">parameter attributes</a>), optional
@@ -896,7 +901,8 @@
<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
optional <a href="#linkage">linkage type</a>, an optional
<a href="#visibility">visibility style</a>, an optional
- <a href="#callingconv">calling convention</a>, a return type, an optional
+ <a href="#callingconv">calling convention</a>,
+ an optional <tt>unnamed_addr</tt> attribute, a return type, an optional
<a href="#paramattrs">parameter attribute</a> for the return type, a function
name, a possibly empty list of arguments, an optional alignment, and an
optional <a href="#gc">garbage collector name</a>.</p>
@@ -922,6 +928,9 @@
specified, the function is forced to have at least that much alignment. All
alignments must be a power of 2.</p>
+<p>If the <tt>unnamed_addr</tt> attribute is given, the address is know to not
+ be significant and two identical functions can be merged</p>.
+
<h5>Syntax:</h5>
<pre class="doc_code">
define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
diff --git a/include/llvm/GlobalValue.h b/include/llvm/GlobalValue.h
index 68cb8e2..ccadc1c 100644
--- a/include/llvm/GlobalValue.h
+++ b/include/llvm/GlobalValue.h
@@ -60,7 +60,8 @@
GlobalValue(const Type *ty, ValueTy vty, Use *Ops, unsigned NumOps,
LinkageTypes linkage, const Twine &Name)
: Constant(ty, vty, Ops, NumOps), Parent(0),
- Linkage(linkage), Visibility(DefaultVisibility), Alignment(0) {
+ Linkage(linkage), Visibility(DefaultVisibility), Alignment(0),
+ UnnamedAddr(0) {
setName(Name);
}
@@ -70,6 +71,7 @@
LinkageTypes Linkage : 5; // The linkage of this global
unsigned Visibility : 2; // The visibility style of this global
unsigned Alignment : 16; // Alignment of this symbol, must be power of two
+ unsigned UnnamedAddr : 1; // This value's address is not significant
std::string Section; // Section to emit this into, empty mean default
public:
~GlobalValue() {
@@ -81,6 +83,9 @@
}
void setAlignment(unsigned Align);
+ bool hasUnnamedAddr() const { return UnnamedAddr; }
+ void setUnnamedAddr(bool Val) { UnnamedAddr = Val; }
+
VisibilityTypes getVisibility() const { return VisibilityTypes(Visibility); }
bool hasDefaultVisibility() const { return Visibility == DefaultVisibility; }
bool hasHiddenVisibility() const { return Visibility == HiddenVisibility; }
diff --git a/lib/AsmParser/LLLexer.cpp b/lib/AsmParser/LLLexer.cpp
index eb5b0f9..857fa1e 100644
--- a/lib/AsmParser/LLLexer.cpp
+++ b/lib/AsmParser/LLLexer.cpp
@@ -509,6 +509,7 @@
KEYWORD(default);
KEYWORD(hidden);
KEYWORD(protected);
+ KEYWORD(unnamed_addr);
KEYWORD(extern_weak);
KEYWORD(external);
KEYWORD(thread_local);
diff --git a/lib/AsmParser/LLParser.cpp b/lib/AsmParser/LLParser.cpp
index 68f7946..5c33d65 100644
--- a/lib/AsmParser/LLParser.cpp
+++ b/lib/AsmParser/LLParser.cpp
@@ -194,7 +194,8 @@
// The Global variable production with no name can have many different
// optional leading prefixes, the production is:
// GlobalVar ::= OptionalLinkage OptionalVisibility OptionalThreadLocal
- // OptionalAddrSpace ('constant'|'global') ...
+ // OptionalAddrSpace OptionalUnNammedAddr
+ // ('constant'|'global') ...
case lltok::kw_private: // OptionalLinkage
case lltok::kw_linker_private: // OptionalLinkage
case lltok::kw_linker_private_weak: // OptionalLinkage
@@ -682,9 +683,9 @@
/// ParseGlobal
/// ::= GlobalVar '=' OptionalLinkage OptionalVisibility OptionalThreadLocal
-/// OptionalAddrSpace GlobalType Type Const
+/// OptionalAddrSpace OptionalUnNammedAddr GlobalType Type Const
/// ::= OptionalLinkage OptionalVisibility OptionalThreadLocal
-/// OptionalAddrSpace GlobalType Type Const
+/// OptionalAddrSpace OptionalUnNammedAddr GlobalType Type Const
///
/// Everything through visibility has been parsed already.
///
@@ -692,12 +693,13 @@
unsigned Linkage, bool HasLinkage,
unsigned Visibility) {
unsigned AddrSpace;
- bool ThreadLocal, IsConstant;
+ bool ThreadLocal, IsConstant, UnnamedAddr;
LocTy TyLoc;
PATypeHolder Ty(Type::getVoidTy(Context));
if (ParseOptionalToken(lltok::kw_thread_local, ThreadLocal) ||
ParseOptionalAddrSpace(AddrSpace) ||
+ ParseOptionalToken(lltok::kw_unnamed_addr, UnnamedAddr) ||
ParseGlobalType(IsConstant) ||
ParseType(Ty, TyLoc))
return true;
@@ -755,6 +757,7 @@
GV->setLinkage((GlobalValue::LinkageTypes)Linkage);
GV->setVisibility((GlobalValue::VisibilityTypes)Visibility);
GV->setThreadLocal(ThreadLocal);
+ GV->setUnnamedAddr(UnnamedAddr);
// Parse attributes on the global.
while (Lex.getKind() == lltok::comma) {
@@ -2657,7 +2660,7 @@
/// FunctionHeader
/// ::= OptionalLinkage OptionalVisibility OptionalCallingConv OptRetAttrs
-/// Type GlobalName '(' ArgList ')' OptFuncAttrs OptSection
+/// OptUnnamedAddr Type GlobalName '(' ArgList ')' OptFuncAttrs OptSection
/// OptionalAlign OptGC
bool LLParser::ParseFunctionHeader(Function *&Fn, bool isDefine) {
// Parse the linkage.
@@ -2665,6 +2668,7 @@
unsigned Linkage;
unsigned Visibility, RetAttrs;
+ bool UnnamedAddr;
CallingConv::ID CC;
PATypeHolder RetType(Type::getVoidTy(Context));
LocTy RetTypeLoc = Lex.getLoc();
@@ -2672,6 +2676,7 @@
ParseOptionalVisibility(Visibility) ||
ParseOptionalCallingConv(CC) ||
ParseOptionalAttrs(RetAttrs, 1) ||
+ ParseOptionalToken(lltok::kw_unnamed_addr, UnnamedAddr) ||
ParseType(RetType, RetTypeLoc, true /*void allowed*/))
return true;
@@ -2841,6 +2846,7 @@
Fn->setVisibility((GlobalValue::VisibilityTypes)Visibility);
Fn->setCallingConv(CC);
Fn->setAttributes(PAL);
+ Fn->setUnnamedAddr(UnnamedAddr);
Fn->setAlignment(Alignment);
Fn->setSection(Section);
if (!GC.empty()) Fn->setGC(GC.c_str());
diff --git a/lib/AsmParser/LLToken.h b/lib/AsmParser/LLToken.h
index 72128c9..576da19 100644
--- a/lib/AsmParser/LLToken.h
+++ b/lib/AsmParser/LLToken.h
@@ -42,6 +42,7 @@
kw_linkonce, kw_linkonce_odr, kw_weak, kw_weak_odr, kw_appending,
kw_dllimport, kw_dllexport, kw_common, kw_available_externally,
kw_default, kw_hidden, kw_protected,
+ kw_unnamed_addr,
kw_extern_weak,
kw_external, kw_thread_local,
kw_zeroinitializer,
diff --git a/lib/Bitcode/Reader/BitcodeReader.cpp b/lib/Bitcode/Reader/BitcodeReader.cpp
index e8b998e..7a71b26 100644
--- a/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -1422,7 +1422,8 @@
break;
}
// GLOBALVAR: [pointer type, isconst, initid,
- // linkage, alignment, section, visibility, threadlocal]
+ // linkage, alignment, section, visibility, threadlocal,
+ // unnamed_addr]
case bitc::MODULE_CODE_GLOBALVAR: {
if (Record.size() < 6)
return Error("Invalid MODULE_CODE_GLOBALVAR record");
@@ -1449,6 +1450,10 @@
if (Record.size() > 7)
isThreadLocal = Record[7];
+ bool UnnamedAddr = false;
+ if (Record.size() > 8)
+ UnnamedAddr = Record[8];
+
GlobalVariable *NewGV =
new GlobalVariable(*TheModule, Ty, isConstant, Linkage, 0, "", 0,
isThreadLocal, AddressSpace);
@@ -1457,6 +1462,7 @@
NewGV->setSection(Section);
NewGV->setVisibility(Visibility);
NewGV->setThreadLocal(isThreadLocal);
+ NewGV->setUnnamedAddr(UnnamedAddr);
ValueList.push_back(NewGV);
@@ -1466,7 +1472,7 @@
break;
}
// FUNCTION: [type, callingconv, isproto, linkage, paramattr,
- // alignment, section, visibility, gc]
+ // alignment, section, visibility, gc, unnamed_addr]
case bitc::MODULE_CODE_FUNCTION: {
if (Record.size() < 8)
return Error("Invalid MODULE_CODE_FUNCTION record");
@@ -1499,6 +1505,10 @@
return Error("Invalid GC ID");
Func->setGC(GCTable[Record[8]-1].c_str());
}
+ bool UnnamedAddr = false;
+ if (Record.size() > 9)
+ UnnamedAddr = Record[9];
+ Func->setUnnamedAddr(UnnamedAddr);
ValueList.push_back(Func);
// If this is a function with a body, remember the prototype we are
diff --git a/lib/Bitcode/Writer/BitcodeWriter.cpp b/lib/Bitcode/Writer/BitcodeWriter.cpp
index 7b6b843..702a611 100644
--- a/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ b/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -404,7 +404,8 @@
unsigned AbbrevToUse = 0;
// GLOBALVAR: [type, isconst, initid,
- // linkage, alignment, section, visibility, threadlocal]
+ // linkage, alignment, section, visibility, threadlocal,
+ // unnamed_addr]
Vals.push_back(VE.getTypeID(GV->getType()));
Vals.push_back(GV->isConstant());
Vals.push_back(GV->isDeclaration() ? 0 :
@@ -413,9 +414,11 @@
Vals.push_back(Log2_32(GV->getAlignment())+1);
Vals.push_back(GV->hasSection() ? SectionMap[GV->getSection()] : 0);
if (GV->isThreadLocal() ||
- GV->getVisibility() != GlobalValue::DefaultVisibility) {
+ GV->getVisibility() != GlobalValue::DefaultVisibility ||
+ GV->hasUnnamedAddr()) {
Vals.push_back(getEncodedVisibility(GV));
Vals.push_back(GV->isThreadLocal());
+ Vals.push_back(GV->hasUnnamedAddr());
} else {
AbbrevToUse = SimpleGVarAbbrev;
}
@@ -427,7 +430,7 @@
// Emit the function proto information.
for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
// FUNCTION: [type, callingconv, isproto, paramattr,
- // linkage, alignment, section, visibility, gc]
+ // linkage, alignment, section, visibility, gc, unnamed_addr]
Vals.push_back(VE.getTypeID(F->getType()));
Vals.push_back(F->getCallingConv());
Vals.push_back(F->isDeclaration());
@@ -437,6 +440,7 @@
Vals.push_back(F->hasSection() ? SectionMap[F->getSection()] : 0);
Vals.push_back(getEncodedVisibility(F));
Vals.push_back(F->hasGC() ? GCMap[F->getGC()] : 0);
+ Vals.push_back(F->hasUnnamedAddr());
unsigned AbbrevToUse = 0;
Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
diff --git a/lib/VMCore/AsmWriter.cpp b/lib/VMCore/AsmWriter.cpp
index 7a1b7dd..3fefbbc 100644
--- a/lib/VMCore/AsmWriter.cpp
+++ b/lib/VMCore/AsmWriter.cpp
@@ -1459,6 +1459,7 @@
if (GV->isThreadLocal()) Out << "thread_local ";
if (unsigned AddressSpace = GV->getType()->getAddressSpace())
Out << "addrspace(" << AddressSpace << ") ";
+ if (GV->hasUnnamedAddr()) Out << "unnamed_addr ";
Out << (GV->isConstant() ? "constant " : "global ");
TypePrinter.print(GV->getType()->getElementType(), Out);
@@ -1589,6 +1590,8 @@
Attributes RetAttrs = Attrs.getRetAttributes();
if (RetAttrs != Attribute::None)
Out << Attribute::getAsString(Attrs.getRetAttributes()) << ' ';
+ if (F->hasUnnamedAddr())
+ Out << "unnamed_addr ";
TypePrinter.print(F->getReturnType(), Out);
Out << ' ';
WriteAsOperandInternal(Out, F, &TypePrinter, &Machine, F->getParent());
diff --git a/lib/VMCore/Verifier.cpp b/lib/VMCore/Verifier.cpp
index 2b87619..58ec6fe 100644
--- a/lib/VMCore/Verifier.cpp
+++ b/lib/VMCore/Verifier.cpp
@@ -484,6 +484,7 @@
"Aliasee cannot be NULL!", &GA);
Assert1(GA.getType() == GA.getAliasee()->getType(),
"Alias and aliasee types should match!", &GA);
+ Assert1(!GA.hasUnnamedAddr(), "Alias cannot have unnamed_addr!", &GA);
if (!isa<GlobalValue>(GA.getAliasee())) {
const ConstantExpr *CE = dyn_cast<ConstantExpr>(GA.getAliasee());
diff --git a/test/Assembler/unnamed-addr.ll b/test/Assembler/unnamed-addr.ll
new file mode 100644
index 0000000..a4828c3
--- /dev/null
+++ b/test/Assembler/unnamed-addr.ll
@@ -0,0 +1,18 @@
+; RUN: llvm-as < %s | llvm-dis | FileCheck %s
+
+%struct.foobar = type { i32 }
+
+@bar.d = internal unnamed_addr constant %struct.foobar zeroinitializer, align 4
+@foo.d = internal constant %struct.foobar zeroinitializer, align 4
+
+define unnamed_addr i32 @main() nounwind ssp {
+entry:
+ %call2 = tail call i32 @zed(%struct.foobar* @foo.d, %struct.foobar* @bar.d) nounwind
+ ret i32 0
+}
+
+declare i32 @zed(%struct.foobar*, %struct.foobar*)
+
+; CHECK: @bar.d = internal unnamed_addr constant %struct.foobar zeroinitializer, align 4
+; CHECK: @foo.d = internal constant %struct.foobar zeroinitializer, align 4
+; CHECK: define unnamed_addr i32 @main() nounwind ssp {
diff --git a/unittests/VMCore/VerifierTest.cpp b/unittests/VMCore/VerifierTest.cpp
index 1173b2d..55ce144 100644
--- a/unittests/VMCore/VerifierTest.cpp
+++ b/unittests/VMCore/VerifierTest.cpp
@@ -10,8 +10,11 @@
#include "llvm/Constants.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Function.h"
+#include "llvm/GlobalAlias.h"
+#include "llvm/GlobalVariable.h"
#include "llvm/Instructions.h"
#include "llvm/LLVMContext.h"
+#include "llvm/Module.h"
#include "llvm/ADT/OwningPtr.h"
#include "llvm/Analysis/Verifier.h"
#include "gtest/gtest.h"
@@ -41,5 +44,22 @@
EXPECT_TRUE(verifyFunction(*F, ReturnStatusAction));
}
+TEST(VerifierTest, AliasUnnamedAddr) {
+ LLVMContext &C = getGlobalContext();
+ Module M("M", C);
+ const Type *Ty = Type::getInt8Ty(C);
+ Constant *Init = Constant::getNullValue(Ty);
+ GlobalVariable *Aliasee = new GlobalVariable(M, Ty, true,
+ GlobalValue::ExternalLinkage,
+ Init, "foo");
+ GlobalAlias *GA = new GlobalAlias(Type::getInt8PtrTy(C),
+ GlobalValue::ExternalLinkage,
+ "bar", Aliasee, &M);
+ GA->setUnnamedAddr(true);
+ std::string Error;
+ EXPECT_TRUE(verifyModule(M, ReturnStatusAction, &Error));
+ EXPECT_TRUE(StringRef(Error).startswith("Alias cannot have unnamed_addr"));
+}
+
}
}