Teach LTOModule to emit linker flags for dllexported symbols, plus interface cleanup.
This change unifies how LTOModule and the backend obtain linker flags
for globals: via a new TargetLoweringObjectFile member function named
emitLinkerFlagsForGlobal. A new function LTOModule::getLinkerOpts() returns
the list of linker flags as a single concatenated string.
This change affects the C libLTO API: the function lto_module_get_*deplibs now
exposes an empty list, and lto_module_get_*linkeropts exposes a single element
which combines the contents of all observed flags. libLTO should never have
tried to parse the linker flags; it is the linker's job to do so. Because
linkers will need to be able to parse flags in regular object files, it
makes little sense for libLTO to have a redundant mechanism for doing so.
The new API is compatible with the old one. It is valid for a user to specify
multiple linker flags in a single pragma directive like this:
#pragma comment(linker, "/defaultlib:foo /defaultlib:bar")
The previous implementation would not have exposed
either flag via lto_module_get_*deplibs (as the test in
TargetLoweringObjectFileCOFF::getDepLibFromLinkerOpt was case sensitive)
and would have exposed "/defaultlib:foo /defaultlib:bar" as a single flag via
lto_module_get_*linkeropts. This may have been a bug in the implementation,
but it does give us a chance to fix the interface.
Differential Revision: http://reviews.llvm.org/D10548
llvm-svn: 241010
diff --git a/llvm/include/llvm-c/lto.h b/llvm/include/llvm-c/lto.h
index 9f37dd7..0ccb0e9 100644
--- a/llvm/include/llvm-c/lto.h
+++ b/llvm/include/llvm-c/lto.h
@@ -282,6 +282,8 @@
/**
* Returns the number of dependent libraries in the object module.
*
+ * Deprecated. Now returns an empty list.
+ *
* \since LTO_API_VERSION=8
*/
extern unsigned int
@@ -291,6 +293,8 @@
/**
* Returns the ith dependent library in the module.
*
+ * Deprecated. Now always returns null.
+ *
* \since LTO_API_VERSION=8
*/
extern const char*
@@ -300,6 +304,9 @@
/**
* Returns the number of linker options in the object module.
*
+ * Each linker option may consist of multiple flags. It is the linker's
+ * responsibility to split the flags using a platform-specific mechanism.
+ *
* \since LTO_API_VERSION=8
*/
extern unsigned int
@@ -309,6 +316,9 @@
/**
* Returns the ith linker option in the module.
*
+ * Each linker option may consist of multiple flags. It is the linker's
+ * responsibility to split the flags using a platform-specific mechanism.
+ *
* \since LTO_API_VERSION=8
*/
extern const char*
diff --git a/llvm/include/llvm/CodeGen/TargetLoweringObjectFileImpl.h b/llvm/include/llvm/CodeGen/TargetLoweringObjectFileImpl.h
index 9a1b63f..10c099d 100644
--- a/llvm/include/llvm/CodeGen/TargetLoweringObjectFileImpl.h
+++ b/llvm/include/llvm/CodeGen/TargetLoweringObjectFileImpl.h
@@ -90,10 +90,6 @@
~TargetLoweringObjectFileMachO() override {}
TargetLoweringObjectFileMachO();
- /// Extract the dependent library name from a linker option string. Returns
- /// StringRef() if the option does not specify a library.
- StringRef getDepLibFromLinkerOpt(StringRef LinkerOption) const override;
-
/// Emit the module flags that specify the garbage collection information.
void emitModuleFlags(MCStreamer &Streamer,
ArrayRef<Module::ModuleFlagEntry> ModuleFlags,
@@ -150,10 +146,6 @@
MCSection *getSectionForJumpTable(const Function &F, Mangler &Mang,
const TargetMachine &TM) const override;
- /// Extract the dependent library name from a linker option string. Returns
- /// StringRef() if the option does not specify a library.
- StringRef getDepLibFromLinkerOpt(StringRef LinkerOption) const override;
-
/// Emit Obj-C garbage collection and linker options. Only linker option
/// emission is implemented for COFF.
void emitModuleFlags(MCStreamer &Streamer,
@@ -164,6 +156,9 @@
const MCSymbol *KeySym) const override;
MCSection *getStaticDtorSection(unsigned Priority,
const MCSymbol *KeySym) const override;
+
+ void emitLinkerFlagsForGlobal(raw_ostream &OS, const GlobalValue *GV,
+ const Mangler &Mang) const override;
};
} // end namespace llvm
diff --git a/llvm/include/llvm/LTO/LTOModule.h b/llvm/include/llvm/LTO/LTOModule.h
index 8204e8f..c4e2be6 100644
--- a/llvm/include/llvm/LTO/LTOModule.h
+++ b/llvm/include/llvm/LTO/LTOModule.h
@@ -47,12 +47,11 @@
std::unique_ptr<LLVMContext> OwnedContext;
+ std::string LinkerOpts;
+
std::unique_ptr<object::IRObjectFile> IRFile;
std::unique_ptr<TargetMachine> _target;
- StringSet<> _linkeropt_strings;
- std::vector<const char *> _deplibs;
- std::vector<const char *> _linkeropts;
- std::vector<NameAndAttributes> _symbols;
+ std::vector<NameAndAttributes> _symbols;
// _defines and _undefines only needed to disambiguate tentative definitions
StringSet<> _defines;
@@ -149,28 +148,8 @@
return nullptr;
}
- /// Get the number of dependent libraries
- uint32_t getDependentLibraryCount() {
- return _deplibs.size();
- }
-
- /// Get the dependent library at the specified index.
- const char *getDependentLibrary(uint32_t index) {
- if (index < _deplibs.size())
- return _deplibs[index];
- return nullptr;
- }
-
- /// Get the number of linker options
- uint32_t getLinkerOptCount() {
- return _linkeropts.size();
- }
-
- /// Get the linker option at the specified index.
- const char *getLinkerOpt(uint32_t index) {
- if (index < _linkeropts.size())
- return _linkeropts[index];
- return nullptr;
+ const char *getLinkerOpts() {
+ return LinkerOpts.c_str();
}
const std::vector<const char*> &getAsmUndefinedRefs() {
diff --git a/llvm/include/llvm/Target/TargetLoweringObjectFile.h b/llvm/include/llvm/Target/TargetLoweringObjectFile.h
index 2a17bd2..5b626c2 100644
--- a/llvm/include/llvm/Target/TargetLoweringObjectFile.h
+++ b/llvm/include/llvm/Target/TargetLoweringObjectFile.h
@@ -64,12 +64,6 @@
const TargetMachine &TM,
const MCSymbol *Sym) const;
- /// Extract the dependent library name from a linker option string. Returns
- /// StringRef() if the option does not specify a library.
- virtual StringRef getDepLibFromLinkerOpt(StringRef LinkerOption) const {
- return StringRef();
- }
-
/// Emit the module flags that the platform cares about.
virtual void emitModuleFlags(MCStreamer &Streamer,
ArrayRef<Module::ModuleFlagEntry> Flags,
@@ -188,6 +182,9 @@
return nullptr;
}
+ virtual void emitLinkerFlagsForGlobal(raw_ostream &OS, const GlobalValue *GV,
+ const Mangler &Mang) const {}
+
protected:
virtual MCSection *SelectSectionForGlobal(const GlobalValue *GV,
SectionKind Kind, Mangler &Mang,