[CodeGen] Emit necessary .note sections for -fsplit-stack
Summary:
According to https://gcc.gnu.org/wiki/SplitStacks, the linker expects a zero-sized .note.GNU-split-stack section if split-stack is used (and also .note.GNU-no-split-stack section if it also contains non-split-stack functions), so it can handle the cases where a split-stack function calls non-split-stack function.
This change adds the sections if needed.
Fixes PR #34670.
Reviewers: thanm, rnk, luqmana
Reviewed By: rnk
Subscribers: llvm-commits
Patch by Cherry Zhang <cherryyz@google.com>
Differential Revision: https://reviews.llvm.org/D38051
llvm-svn: 314335
diff --git a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
index ee5cb35..26ca58a 100644
--- a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
@@ -1382,6 +1382,16 @@
PtrSize);
}
+ // Emit .note.GNU-split-stack and .note.GNU-no-split-stack sections if
+ // split-stack is used.
+ if (TM.getTargetTriple().isOSBinFormatELF() && MMI->hasSplitStack()) {
+ OutStreamer->SwitchSection(
+ OutContext.getELFSection(".note.GNU-split-stack", ELF::SHT_PROGBITS, 0));
+ if (MMI->hasNosplitStack())
+ OutStreamer->SwitchSection(
+ OutContext.getELFSection(".note.GNU-no-split-stack", ELF::SHT_PROGBITS, 0));
+ }
+
// If we don't have any trampolines, then we don't require stack memory
// to be executable. Some targets have a directive to declare this.
Function *InitTrampolineIntrinsic = M.getFunction("llvm.init.trampoline");