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/tools/lto/lto.cpp b/llvm/tools/lto/lto.cpp
index e55708c..c77702d 100644
--- a/llvm/tools/lto/lto.cpp
+++ b/llvm/tools/lto/lto.cpp
@@ -224,19 +224,21 @@
}
unsigned int lto_module_get_num_deplibs(lto_module_t mod) {
- return unwrap(mod)->getDependentLibraryCount();
+ return 0;
}
const char* lto_module_get_deplib(lto_module_t mod, unsigned int index) {
- return unwrap(mod)->getDependentLibrary(index);
+ return nullptr;
}
unsigned int lto_module_get_num_linkeropts(lto_module_t mod) {
- return unwrap(mod)->getLinkerOptCount();
+ return 1;
}
const char* lto_module_get_linkeropt(lto_module_t mod, unsigned int index) {
- return unwrap(mod)->getLinkerOpt(index);
+ if (index != 0)
+ return nullptr;
+ return unwrap(mod)->getLinkerOpts();
}
void lto_codegen_set_diagnostic_handler(lto_code_gen_t cg,