[IR] make -stack-alignment= into a module attr

Similar to D102742, specifying the stack alignment via CodegenOpts means
that this flag gets dropped during LTO, unless the command line is
re-specified as a plugin opt. Instead, encode this information as a
module level attribute so that we don't have to expose this llvm
internal flag when linking the Linux kernel with LTO.

Looks like external dependencies might need a fix:
* https://github.com/llvm-hs/llvm-hs/issues/345
* https://github.com/halide/Halide/issues/6079

Link: https://github.com/ClangBuiltLinux/linux/issues/1377

Reviewed By: tejohnson

Differential Revision: https://reviews.llvm.org/D103048

1 files changed, 0 insertions, 7 deletions

diff --git a/llvm/lib/CodeGen/CommandFlags.cpp b/llvm/lib/CodeGen/CommandFlags.cpp
index a7f6ca4..f3cba62 100644
--- a/llvm/lib/CodeGen/CommandFlags.cpp
+++ b/llvm/lib/CodeGen/CommandFlags.cpp
@@ -69,7 +69,6 @@ CGOPT(bool, DontPlaceZerosInBSS)
 CGOPT(bool, EnableGuaranteedTailCallOpt)
 CGOPT(bool, DisableTailCalls)
 CGOPT(bool, StackSymbolOrdering)
-CGOPT(unsigned, OverrideStackAlignment)
 CGOPT(bool, StackRealign)
 CGOPT(std::string, TrapFuncName)
 CGOPT(bool, UseCtors)
@@ -305,11 +304,6 @@ codegen::RegisterCodeGenFlags::RegisterCodeGenFlags() {
       cl::init(true));
   CGBINDOPT(StackSymbolOrdering);
 
-  static cl::opt<unsigned> OverrideStackAlignment(
-      "stack-alignment", cl::desc("Override default stack alignment"),
-      cl::init(0));
-  CGBINDOPT(OverrideStackAlignment);
-
   static cl::opt<bool> StackRealign(
       "stackrealign",
       cl::desc("Force align the stack to the minimum alignment"),
@@ -508,7 +502,6 @@ codegen::InitTargetOptionsFromCodeGenFlags(const Triple &TheTriple) {
   Options.EnableAIXExtendedAltivecABI = getEnableAIXExtendedAltivecABI();
   Options.NoZerosInBSS = getDontPlaceZerosInBSS();
   Options.GuaranteedTailCallOpt = getEnableGuaranteedTailCallOpt();
-  Options.StackAlignmentOverride = getOverrideStackAlignment();
   Options.StackSymbolOrdering = getStackSymbolOrdering();
   Options.UseInitArray = !getUseCtors();
   Options.RelaxELFRelocations = getRelaxELFRelocations();