Decouple dllexport/dllimport from linkage
Representing dllexport/dllimport as distinct linkage types prevents using
these attributes on templates and inline functions.
Instead of introducing further mixed linkage types to include linkonce and
weak ODR, the old import/export linkage types are replaced with a new
separate visibility-like specifier:
define available_externally dllimport void @f() {}
@Var = dllexport global i32 1, align 4
Linkage for dllexported globals and functions is now equal to their linkage
without dllexport. Imported globals and functions must be either
declarations with external linkage, or definitions with
AvailableExternallyLinkage.
llvm-svn: 199218
diff --git a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
index 39a0dfa..81ed803b 100644
--- a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -80,8 +80,8 @@
case 2: return GlobalValue::AppendingLinkage;
case 3: return GlobalValue::InternalLinkage;
case 4: return GlobalValue::LinkOnceAnyLinkage;
- case 5: return GlobalValue::DLLImportLinkage;
- case 6: return GlobalValue::DLLExportLinkage;
+ case 5: return GlobalValue::ExternalLinkage; // Obsolete DLLImportLinkage
+ case 6: return GlobalValue::ExternalLinkage; // Obsolete DLLExportLinkage
case 7: return GlobalValue::ExternalWeakLinkage;
case 8: return GlobalValue::CommonLinkage;
case 9: return GlobalValue::PrivateLinkage;
@@ -102,6 +102,16 @@
}
}
+static GlobalValue::DLLStorageClassTypes
+GetDecodedDLLStorageClass(unsigned Val) {
+ switch (Val) {
+ default: // Map unknown values to default.
+ case 0: return GlobalValue::DefaultStorageClass;
+ case 1: return GlobalValue::DLLImportStorageClass;
+ case 2: return GlobalValue::DLLExportStorageClass;
+ }
+}
+
static GlobalVariable::ThreadLocalMode GetDecodedThreadLocalMode(unsigned Val) {
switch (Val) {
case 0: return GlobalVariable::NotThreadLocal;
@@ -193,6 +203,13 @@
}
}
+static void UpgradeDLLImportExportLinkage(llvm::GlobalValue *GV, unsigned Val) {
+ switch (Val) {
+ case 5: GV->setDLLStorageClass(GlobalValue::DLLImportStorageClass); break;
+ case 6: GV->setDLLStorageClass(GlobalValue::DLLExportStorageClass); break;
+ }
+}
+
namespace llvm {
namespace {
/// @brief A class for maintaining the slot number definition
@@ -1797,7 +1814,7 @@
}
// GLOBALVAR: [pointer type, isconst, initid,
// linkage, alignment, section, visibility, threadlocal,
- // unnamed_addr]
+ // unnamed_addr, dllstorageclass]
case bitc::MODULE_CODE_GLOBALVAR: {
if (Record.size() < 6)
return Error(InvalidRecord);
@@ -1843,6 +1860,11 @@
NewGV->setVisibility(Visibility);
NewGV->setUnnamedAddr(UnnamedAddr);
+ if (Record.size() > 10)
+ NewGV->setDLLStorageClass(GetDecodedDLLStorageClass(Record[10]));
+ else
+ UpgradeDLLImportExportLinkage(NewGV, Record[3]);
+
ValueList.push_back(NewGV);
// Remember which value to use for the global initializer.
@@ -1851,7 +1873,8 @@
break;
}
// FUNCTION: [type, callingconv, isproto, linkage, paramattr,
- // alignment, section, visibility, gc, unnamed_addr]
+ // alignment, section, visibility, gc, unnamed_addr,
+ // dllstorageclass]
case bitc::MODULE_CODE_FUNCTION: {
if (Record.size() < 8)
return Error(InvalidRecord);
@@ -1891,6 +1914,12 @@
Func->setUnnamedAddr(UnnamedAddr);
if (Record.size() > 10 && Record[10] != 0)
FunctionPrefixes.push_back(std::make_pair(Func, Record[10]-1));
+
+ if (Record.size() > 11)
+ Func->setDLLStorageClass(GetDecodedDLLStorageClass(Record[11]));
+ else
+ UpgradeDLLImportExportLinkage(Func, Record[3]);
+
ValueList.push_back(Func);
// If this is a function with a body, remember the prototype we are
@@ -1902,7 +1931,7 @@
break;
}
// ALIAS: [alias type, aliasee val#, linkage]
- // ALIAS: [alias type, aliasee val#, linkage, visibility]
+ // ALIAS: [alias type, aliasee val#, linkage, visibility, dllstorageclass]
case bitc::MODULE_CODE_ALIAS: {
if (Record.size() < 3)
return Error(InvalidRecord);
@@ -1917,6 +1946,10 @@
// Old bitcode files didn't have visibility field.
if (Record.size() > 3)
NewGA->setVisibility(GetDecodedVisibility(Record[3]));
+ if (Record.size() > 4)
+ NewGA->setDLLStorageClass(GetDecodedDLLStorageClass(Record[4]));
+ else
+ UpgradeDLLImportExportLinkage(NewGA, Record[2]);
ValueList.push_back(NewGA);
AliasInits.push_back(std::make_pair(NewGA, Record[1]));
break;