From 82eb871e99995946c6f0a60d04ba8e282c8056e9 Mon Sep 17 00:00:00 2001
From: Jameson Nash <vtjnash@gmail.com>
Date: Tue, 16 Mar 2021 16:37:00 -0400
Subject: [PATCH] add stack-probes to make stack-overflow detection more
 reliable

Supported platforms are currently X86, PowerPC, and SystemZ.

Fixes #25523
Fixes #36170
Closes #28577
Closes #30892
---
 src/codegen.cpp             | 35 +++++++++++++++--------------------
 test/llvmpasses/noinline.jl |  2 +-
 2 files changed, 16 insertions(+), 21 deletions(-)

diff --git a/src/codegen.cpp b/src/codegen.cpp
index f0edf7b19fa29..b3acb943b3150 100644
--- a/src/codegen.cpp
+++ b/src/codegen.cpp
@@ -1719,6 +1719,14 @@ static void jl_init_function(Function *F)
     F->addFnAttr("no-frame-pointer-elim", "true");
 #endif
 #endif
+#if JL_LLVM_VERSION >= 110000 && !defined(JL_ASAN_ENABLED) && !defined(_OS_WINDOWS_)
+    // ASAN won't like us accessing undefined memory causing spurious issues,
+    // and Windows has platform-specific handling which causes it to mishandle
+    // this annotation. Other platforms should just ignore this if they don't
+    // implement it.
+    F->addFnAttr("probe-stack", "inline-asm");
+    //F->addFnAttr("stack-probe-size", 4096); // can use this to change the default
+#endif
 }
 
 static std::pair<bool, bool> uses_specsig(jl_method_instance_t *lam, jl_value_t *rettype, bool prefer_specsig)
@@ -6297,20 +6305,7 @@ static std::pair<std::unique_ptr<Module>, jl_llvm_functions_t>
         }
     }
 
-    /*
-    // step 6. (optional) check for stack overflow (the slower way)
-    Value *cur_sp =
-        ctx.builder.CreateCall(Intrinsic::getDeclaration(M,
-                                                     Intrinsic::frameaddress),
-                           ConstantInt::get(T_int32, 0));
-    Value *sp_ok =
-        ctx.builder.CreateICmpUGT(cur_sp,
-                              ConstantInt::get(T_size,
-                                               (uptrint_t)jl_stack_lo));
-    error_unless(ctx, sp_ok, "stack overflow");
-    */
-
-    // step 7. set up GC frame
+    // step 6. set up GC frame
     allocate_gc_frame(ctx, b0);
     Value *last_age = NULL;
     emit_last_age_field(ctx);
@@ -6318,7 +6313,7 @@ static std::pair<std::unique_ptr<Module>, jl_llvm_functions_t>
         last_age = tbaa_decorate(tbaa_gcframe, ctx.builder.CreateAlignedLoad(ctx.world_age_field, Align(sizeof(size_t))));
     }
 
-    // step 8. allocate local variables slots
+    // step 7. allocate local variables slots
     // must be in the first basic block for the llvm mem2reg pass to work
     auto allocate_local = [&](jl_varinfo_t &varinfo, jl_sym_t *s) {
         jl_value_t *jt = varinfo.value.typ;
@@ -6436,7 +6431,7 @@ static std::pair<std::unique_ptr<Module>, jl_llvm_functions_t>
         }
     }
 
-    // step 9. move args into local variables
+    // step 8. move args into local variables
     Function::arg_iterator AI = f->arg_begin();
 
     auto get_specsig_arg = [&](jl_value_t *argType, Type *llvmArgType, bool isboxed) {
@@ -6566,7 +6561,7 @@ static std::pair<std::unique_ptr<Module>, jl_llvm_functions_t>
         }
     }
 
-    // step 10. allocate rest argument
+    // step 9. allocate rest argument
     CallInst *restTuple = NULL;
     if (va && ctx.vaSlot != -1) {
         jl_varinfo_t &vi = ctx.slots[ctx.vaSlot];
@@ -6608,7 +6603,7 @@ static std::pair<std::unique_ptr<Module>, jl_llvm_functions_t>
         }
     }
 
-    // step 11. Compute properties for each statements
+    // step 10. Compute properties for each statements
     //     This needs to be computed by iterating in the IR order
     //     instead of control flow order.
     auto in_user_mod = [] (jl_module_t *mod) {
@@ -6730,7 +6725,7 @@ static std::pair<std::unique_ptr<Module>, jl_llvm_functions_t>
     Instruction &prologue_end = ctx.builder.GetInsertBlock()->back();
 
 
-    // step 12. Do codegen in control flow order
+    // step 11. Do codegen in control flow order
     std::vector<int> workstack;
     std::map<int, BasicBlock*> BB;
     std::map<size_t, BasicBlock*> come_from_bb;
@@ -7288,7 +7283,7 @@ static std::pair<std::unique_ptr<Module>, jl_llvm_functions_t>
         PN->eraseFromParent();
     }
 
-    // step 13. Perform any delayed instantiations
+    // step 12. Perform any delayed instantiations
     if (ctx.debug_enabled) {
         bool in_prologue = true;
         for (auto &BB : *ctx.f) {
diff --git a/test/llvmpasses/noinline.jl b/test/llvmpasses/noinline.jl
index f542968b21979..c4aa22bf80a71 100644
--- a/test/llvmpasses/noinline.jl
+++ b/test/llvmpasses/noinline.jl
@@ -17,5 +17,5 @@ include(joinpath("..", "testhelpers", "llvmpasses.jl"))
     return A + B
 end
 
-# CHECK: attributes #{{[0-9]+}} = {{{([a-z]+ )*}} noinline {{([a-z]+ )*}}}
+# CHECK: attributes #{{[0-9]+}} = {{{[^}]*}} noinline {{[^}]*}}}
 emit(simple_noinline, Float64, Float64)