[IR] convert warn-stack-size from module flag to fn attr

Otherwise, this causes issues when building with LTO for object files
that use different values.

Link: https://github.com/ClangBuiltLinux/linux/issues/1395

Reviewed By: dblaikie, MaskRay

Differential Revision: https://reviews.llvm.org/D104342

1 files changed, 10 insertions, 1 deletions

diff --git a/llvm/lib/CodeGen/PrologEpilogInserter.cpp b/llvm/lib/CodeGen/PrologEpilogInserter.cpp
index e09face1..e745f56 100644
--- a/llvm/lib/CodeGen/PrologEpilogInserter.cpp
+++ b/llvm/lib/CodeGen/PrologEpilogInserter.cpp
@@ -274,7 +274,16 @@ bool PEI::runOnMachineFunction(MachineFunction &MF) {
   MachineFrameInfo &MFI = MF.getFrameInfo();
   uint64_t StackSize = MFI.getStackSize();
 
-  unsigned Threshold = MF.getFunction().getParent()->getWarnStackSize();
+  unsigned Threshold = UINT_MAX;
+  if (MF.getFunction().hasFnAttribute("warn-stack-size")) {
+    bool Failed = MF.getFunction()
+                      .getFnAttribute("warn-stack-size")
+                      .getValueAsString()
+                      .getAsInteger(10, Threshold);
+    // Verifier should have caught this.
+    assert(!Failed && "Invalid warn-stack-size fn attr value");
+    (void)Failed;
+  }
   if (StackSize > Threshold) {
     DiagnosticInfoStackSize DiagStackSize(F, StackSize);
     F.getContext().diagnose(DiagStackSize);