Add a new "available_externally" linkage type. This is intended
to support C99 inline, GNU extern inline, etc. Related bugzilla's
include PR3517, PR3100, & PR2933. Nothing uses this yet, but it
appears to work.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@68940 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/docs/LangRef.html b/docs/LangRef.html
index 457a56a..8ec1123 100644
--- a/docs/LangRef.html
+++ b/docs/LangRef.html
@@ -509,6 +509,17 @@
'<tt>static</tt>' keyword in C.
</dd>
+ <dt><tt><b><a name="available_externally">available_externally</a></b></tt>:
+ </dt>
+
+ <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
+ into the object file corresponding to the LLVM module. They exist to
+ allow inlining and other optimizations to take place given knowledge of the
+ definition of the global, which is known to be somewhere outside the module.
+ Globals with <tt>available_externally</tt> linkage are allowed to be discarded
+ at will, and are otherwise the same as <tt>linkonce_odr</tt>. This linkage
+ type is only allowed on definitions, not declarations.</dd>
+
<dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
<dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
@@ -554,10 +565,10 @@
<dt><tt><b><a name="linkage_linkonce">linkonce_odr</a></b></tt>: </dt>
<dt><tt><b><a name="linkage_weak">weak_odr</a></b></tt>: </dt>
- <dd>Some languages allow inequivalent globals to be merged, such as two
+ <dd>Some languages allow differing globals to be merged, such as two
functions with different semantics. Other languages, such as <tt>C++</tt>,
ensure that only equivalent globals are ever merged (the "one definition
- rule" - <tt>odr</tt>). Such languages can use the <tt>linkonce_odr</tt>
+ rule" - "ODR"). Such languages can use the <tt>linkonce_odr</tt>
and <tt>weak_odr</tt> linkage types to indicate that the global will only
be merged with equivalent globals. These linkage types are otherwise the
same as their non-<tt>odr</tt> versions.
diff --git a/include/llvm/CodeGen/MachineFunctionPass.h b/include/llvm/CodeGen/MachineFunctionPass.h
index 95bb2bf..6b5e64a 100644
--- a/include/llvm/CodeGen/MachineFunctionPass.h
+++ b/include/llvm/CodeGen/MachineFunctionPass.h
@@ -24,8 +24,9 @@
namespace llvm {
+ // FIXME: This pass should declare that the pass does not invalidate any LLVM
+ // passes.
struct MachineFunctionPass : public FunctionPass {
-
explicit MachineFunctionPass(intptr_t ID) : FunctionPass(ID) {}
explicit MachineFunctionPass(void *ID) : FunctionPass(ID) {}
@@ -36,14 +37,7 @@
virtual bool runOnMachineFunction(MachineFunction &MF) = 0;
public:
- // FIXME: This pass should declare that the pass does not invalidate any LLVM
- // passes.
- bool runOnFunction(Function &F) {
- return runOnMachineFunction(MachineFunction::get(&F));
- }
-
-private:
- virtual void virtfn(); // out of line virtual fn to give class a home.
+ bool runOnFunction(Function &F);
};
} // End llvm namespace
diff --git a/include/llvm/GlobalValue.h b/include/llvm/GlobalValue.h
index e6a82ef..50c613e 100644
--- a/include/llvm/GlobalValue.h
+++ b/include/llvm/GlobalValue.h
@@ -31,6 +31,7 @@
/// @brief An enumeration for the kinds of linkage for global values.
enum LinkageTypes {
ExternalLinkage = 0,///< Externally visible function
+ AvailableExternallyLinkage, ///< Available for inspection, not emission.
LinkOnceAnyLinkage, ///< Keep one copy of function when linking (inline)
LinkOnceODRLinkage, ///< Same, but only replaced by something equivalent.
WeakAnyLinkage, ///< Keep one copy of named function when linking (weak)
@@ -109,6 +110,9 @@
}
bool hasExternalLinkage() const { return Linkage == ExternalLinkage; }
+ bool hasAvailableExternallyLinkage() const {
+ return Linkage == AvailableExternallyLinkage;
+ }
bool hasLinkOnceLinkage() const {
return Linkage == LinkOnceAnyLinkage || Linkage == LinkOnceODRLinkage;
}
@@ -119,7 +123,8 @@
bool hasInternalLinkage() const { return Linkage == InternalLinkage; }
bool hasPrivateLinkage() const { return Linkage == PrivateLinkage; }
bool hasLocalLinkage() const {
- return Linkage == InternalLinkage || Linkage == PrivateLinkage;
+ return Linkage == InternalLinkage || Linkage == PrivateLinkage ||
+ Linkage == AvailableExternallyLinkage;
}
bool hasDLLImportLinkage() const { return Linkage == DLLImportLinkage; }
bool hasDLLExportLinkage() const { return Linkage == DLLExportLinkage; }
@@ -141,9 +146,10 @@
}
/// isWeakForLinker - Whether the definition of this global may be replaced at
- /// link time, whether the replacement is equivalent to the original or not.
+ /// link time.
bool isWeakForLinker() const {
- return (Linkage == WeakAnyLinkage ||
+ return (Linkage == AvailableExternallyLinkage ||
+ Linkage == WeakAnyLinkage ||
Linkage == WeakODRLinkage ||
Linkage == LinkOnceAnyLinkage ||
Linkage == LinkOnceODRLinkage ||
diff --git a/lib/AsmParser/LLLexer.cpp b/lib/AsmParser/LLLexer.cpp
index d4815d8..b227af2 100644
--- a/lib/AsmParser/LLLexer.cpp
+++ b/lib/AsmParser/LLLexer.cpp
@@ -487,6 +487,7 @@
KEYWORD(private);
KEYWORD(internal);
+ KEYWORD(available_externally);
KEYWORD(linkonce);
KEYWORD(linkonce_odr);
KEYWORD(weak);
diff --git a/lib/AsmParser/LLParser.cpp b/lib/AsmParser/LLParser.cpp
index 177161e..d92957a 100644
--- a/lib/AsmParser/LLParser.cpp
+++ b/lib/AsmParser/LLParser.cpp
@@ -764,6 +764,9 @@
case lltok::kw_weak_odr: Res = GlobalValue::WeakODRLinkage; break;
case lltok::kw_linkonce: Res = GlobalValue::LinkOnceAnyLinkage; break;
case lltok::kw_linkonce_odr: Res = GlobalValue::LinkOnceODRLinkage; break;
+ case lltok::kw_available_externally:
+ Res = GlobalValue::AvailableExternallyLinkage;
+ break;
case lltok::kw_appending: Res = GlobalValue::AppendingLinkage; break;
case lltok::kw_dllexport: Res = GlobalValue::DLLExportLinkage; break;
case lltok::kw_common: Res = GlobalValue::CommonLinkage; break;
diff --git a/lib/AsmParser/LLToken.h b/lib/AsmParser/LLToken.h
index 35cb4db..d8bd38a 100644
--- a/lib/AsmParser/LLToken.h
+++ b/lib/AsmParser/LLToken.h
@@ -37,7 +37,7 @@
kw_global, kw_constant,
kw_private, kw_internal, kw_linkonce, kw_linkonce_odr, kw_weak, kw_weak_odr,
- kw_appending, kw_dllimport, kw_dllexport, kw_common,
+ kw_appending, kw_dllimport, kw_dllexport, kw_common,kw_available_externally,
kw_default, kw_hidden, kw_protected,
kw_extern_weak,
kw_external, kw_thread_local,
diff --git a/lib/Bitcode/Reader/BitcodeReader.cpp b/lib/Bitcode/Reader/BitcodeReader.cpp
index 6f91dda..8079acd 100644
--- a/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -70,6 +70,7 @@
case 9: return GlobalValue::PrivateLinkage;
case 10: return GlobalValue::WeakODRLinkage;
case 11: return GlobalValue::LinkOnceODRLinkage;
+ case 12: return GlobalValue::AvailableExternallyLinkage;
}
}
diff --git a/lib/Bitcode/Writer/BitcodeWriter.cpp b/lib/Bitcode/Writer/BitcodeWriter.cpp
index c836d39..1937c7e 100644
--- a/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ b/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -287,6 +287,7 @@
case GlobalValue::PrivateLinkage: return 9;
case GlobalValue::WeakODRLinkage: return 10;
case GlobalValue::LinkOnceODRLinkage: return 11;
+ case GlobalValue::AvailableExternallyLinkage: return 12;
}
}
diff --git a/lib/CodeGen/AsmPrinter/AsmPrinter.cpp b/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
index d19e9af..0979ced 100644
--- a/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ b/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
@@ -443,7 +443,9 @@
}
// Ignore debug and non-emitted data.
- if (GV->getSection() == "llvm.metadata") return true;
+ if (GV->getSection() == "llvm.metadata" ||
+ GV->hasAvailableExternallyLinkage())
+ return true;
if (!GV->hasAppendingLinkage()) return false;
diff --git a/lib/CodeGen/AsmPrinter/DwarfWriter.cpp b/lib/CodeGen/AsmPrinter/DwarfWriter.cpp
index d59609b..4582f4a 100644
--- a/lib/CodeGen/AsmPrinter/DwarfWriter.cpp
+++ b/lib/CodeGen/AsmPrinter/DwarfWriter.cpp
@@ -3519,6 +3519,9 @@
///
void EmitEHFrame(const FunctionEHFrameInfo &EHFrameInfo) {
Function::LinkageTypes linkage = EHFrameInfo.function->getLinkage();
+
+ assert(!EHFrameInfo.function->hasAvailableExternallyLinkage() &&
+ "Should not emit 'available externally' functions at all");
Asm->SwitchToTextSection(TAI->getDwarfEHFrameSection());
diff --git a/lib/CodeGen/MachineFunction.cpp b/lib/CodeGen/MachineFunction.cpp
index bd7105f..18a040e 100644
--- a/lib/CodeGen/MachineFunction.cpp
+++ b/lib/CodeGen/MachineFunction.cpp
@@ -38,8 +38,14 @@
static AnnotationID MF_AID(
AnnotationManager::getID("CodeGen::MachineCodeForFunction"));
-// Out of line virtual function to home classes.
-void MachineFunctionPass::virtfn() {}
+bool MachineFunctionPass::runOnFunction(Function &F) {
+ // Do not codegen any 'available_externally' functions at all, they have
+ // definitions outside the translation unit.
+ if (F.hasAvailableExternallyLinkage())
+ return false;
+
+ return runOnMachineFunction(MachineFunction::get(&F));
+}
namespace {
struct VISIBILITY_HIDDEN Printer : public MachineFunctionPass {
diff --git a/lib/Linker/LinkModules.cpp b/lib/Linker/LinkModules.cpp
index 0ca4e10..4a15d88 100644
--- a/lib/Linker/LinkModules.cpp
+++ b/lib/Linker/LinkModules.cpp
@@ -480,9 +480,10 @@
} else if (Src->isWeakForLinker()) {
// At this point we know that Dest has LinkOnce, External*, Weak, Common,
// or DLL* linkage.
- if ((Dest->hasLinkOnceLinkage() &&
- (Src->hasWeakLinkage() || Src->hasCommonLinkage())) ||
- Dest->hasExternalWeakLinkage()) {
+ if (Dest->hasExternalWeakLinkage() ||
+ Dest->hasAvailableExternallyLinkage() ||
+ (Dest->hasLinkOnceLinkage() &&
+ (Src->hasWeakLinkage() || Src->hasCommonLinkage()))) {
LinkFromSrc = true;
LT = Src->getLinkage();
} else {
diff --git a/lib/Target/CppBackend/CPPBackend.cpp b/lib/Target/CppBackend/CPPBackend.cpp
index 8262408..e89d5f9 100644
--- a/lib/Target/CppBackend/CPPBackend.cpp
+++ b/lib/Target/CppBackend/CPPBackend.cpp
@@ -294,6 +294,8 @@
Out << "GlobalValue::InternalLinkage"; break;
case GlobalValue::PrivateLinkage:
Out << "GlobalValue::PrivateLinkage"; break;
+ case GlobalValue::AvailableExternallyLinkage:
+ Out << "GlobalValue::AvailableExternallyLinkage "; break;
case GlobalValue::LinkOnceAnyLinkage:
Out << "GlobalValue::LinkOnceAnyLinkage "; break;
case GlobalValue::LinkOnceODRLinkage:
diff --git a/lib/VMCore/AsmWriter.cpp b/lib/VMCore/AsmWriter.cpp
index b1bf42e..e4dd9d6 100644
--- a/lib/VMCore/AsmWriter.cpp
+++ b/lib/VMCore/AsmWriter.cpp
@@ -1225,6 +1225,9 @@
switch (LT) {
case GlobalValue::PrivateLinkage: Out << "private "; break;
case GlobalValue::InternalLinkage: Out << "internal "; break;
+ case GlobalValue::AvailableExternallyLinkage:
+ Out << "available_externally ";
+ break;
case GlobalValue::LinkOnceAnyLinkage: Out << "linkonce "; break;
case GlobalValue::LinkOnceODRLinkage: Out << "linkonce_odr "; break;
case GlobalValue::WeakAnyLinkage: Out << "weak "; break;
diff --git a/test/CodeGen/Generic/externally_available.ll b/test/CodeGen/Generic/externally_available.ll
new file mode 100644
index 0000000..73b6b98
--- /dev/null
+++ b/test/CodeGen/Generic/externally_available.ll
@@ -0,0 +1,10 @@
+; RUN: llvm-as < %s | llc | not grep test_
+
+; test_function should not be emitted to the .s file.
+define available_externally i32 @test_function() {
+ ret i32 4
+}
+
+; test_global should not be emitted to the .s file.
+@test_global = available_externally global i32 4
+
diff --git a/test/Transforms/GlobalDCE/externally_available.ll b/test/Transforms/GlobalDCE/externally_available.ll
new file mode 100644
index 0000000..ccdf7e1
--- /dev/null
+++ b/test/Transforms/GlobalDCE/externally_available.ll
@@ -0,0 +1,10 @@
+; RUN: llvm-as < %s | opt -globaldce | llvm-dis | not grep test_
+
+; test_function should not be emitted to the .s file.
+define available_externally i32 @test_function() {
+ ret i32 4
+}
+
+; test_global should not be emitted to the .s file.
+@test_global = available_externally global i32 4
+
diff --git a/test/Transforms/Inline/externally_available.ll b/test/Transforms/Inline/externally_available.ll
new file mode 100644
index 0000000..68f7d65
--- /dev/null
+++ b/test/Transforms/Inline/externally_available.ll
@@ -0,0 +1,16 @@
+; RUN: llvm-as < %s | opt -inline -constprop | llvm-dis > %t
+; RUN: not grep test_function %t
+; RUN: grep {ret i32 5} %t
+
+
+; test_function should not be emitted to the .s file.
+define available_externally i32 @test_function() {
+ ret i32 4
+}
+
+
+define i32 @result() {
+ %A = call i32 @test_function()
+ %B = add i32 %A, 1
+ ret i32 %B
+}
\ No newline at end of file
diff --git a/test/Transforms/InstCombine/odr-linkage.ll b/test/Transforms/InstCombine/odr-linkage.ll
new file mode 100644
index 0000000..96f8833
--- /dev/null
+++ b/test/Transforms/InstCombine/odr-linkage.ll
@@ -0,0 +1,19 @@
+; RUN: llvm-as < %s | opt -instcombine | llvm-dis | grep {ret i32 10}
+
+@g1 = available_externally constant i32 1
+@g2 = linkonce_odr constant i32 2
+@g3 = weak_odr constant i32 3
+@g4 = internal constant i32 4
+
+define i32 @test() {
+ %A = load i32* @g1
+ %B = load i32* @g2
+ %C = load i32* @g3
+ %D = load i32* @g4
+
+ %a = add i32 %A, %B
+ %b = add i32 %a, %C
+ %c = add i32 %b, %D
+ ret i32 %c
+}
+
\ No newline at end of file
diff --git a/tools/llvm-nm/llvm-nm.cpp b/tools/llvm-nm/llvm-nm.cpp
index 3449510..324e0f6 100644
--- a/tools/llvm-nm/llvm-nm.cpp
+++ b/tools/llvm-nm/llvm-nm.cpp
@@ -69,7 +69,6 @@
}
static char TypeCharForSymbol(GlobalValue &GV) {
- /* FIXME: what to do with private linkage? */
if (GV.isDeclaration()) return 'U';
if (GV.hasLinkOnceLinkage()) return 'C';
if (GV.hasCommonLinkage()) return 'C';
@@ -87,8 +86,11 @@
}
static void DumpSymbolNameForGlobalValue(GlobalValue &GV) {
+ // Private linkage and available_externally linkage don't exist in symtab.
+ if (GV.hasPrivateLinkage() || GV.hasAvailableExternallyLinkage()) return;
+
const std::string SymbolAddrStr = " "; // Not used yet...
- char TypeChar = TypeCharForSymbol (GV);
+ char TypeChar = TypeCharForSymbol(GV);
if ((TypeChar != 'U') && UndefinedOnly)
return;
if ((TypeChar == 'U') && DefinedOnly)
@@ -96,17 +98,17 @@
if (GV.hasLocalLinkage () && ExternalOnly)
return;
if (OutputFormat == posix) {
- std::cout << GV.getName () << " " << TypeCharForSymbol (GV) << " "
+ std::cout << GV.getName () << " " << TypeCharForSymbol(GV) << " "
<< SymbolAddrStr << "\n";
} else if (OutputFormat == bsd) {
- std::cout << SymbolAddrStr << " " << TypeCharForSymbol (GV) << " "
+ std::cout << SymbolAddrStr << " " << TypeCharForSymbol(GV) << " "
<< GV.getName () << "\n";
} else if (OutputFormat == sysv) {
std::string PaddedName (GV.getName ());
while (PaddedName.length () < 20)
PaddedName += " ";
std::cout << PaddedName << "|" << SymbolAddrStr << "| "
- << TypeCharForSymbol (GV)
+ << TypeCharForSymbol(GV)
<< " | | | |\n";
}
}
@@ -122,10 +124,10 @@
<< "Name Value Class Type"
<< " Size Line Section\n";
}
- std::for_each (M->begin (), M->end (), DumpSymbolNameForGlobalValue);
- std::for_each (M->global_begin (), M->global_end (),
+ std::for_each (M->begin(), M->end(), DumpSymbolNameForGlobalValue);
+ std::for_each (M->global_begin(), M->global_end(),
DumpSymbolNameForGlobalValue);
- std::for_each (M->alias_begin (), M->alias_end (),
+ std::for_each (M->alias_begin(), M->alias_end(),
DumpSymbolNameForGlobalValue);
}