[PATCH] D92738: [CodeGen] Restore accessing __stack_chk_guard via a .refptr stub on mingw after 2518433f861fcb87

[Martin Storsjö via Phabricator via llvm-commits]

mstorsjo created this revision.
mstorsjo added reviewers: MaskRay, rnk.
Herald added subscribers: pengfei, hiraditya, kristof.beyls.
mstorsjo requested review of this revision.
Herald added a project: LLVM.

Add tests for this particular detail for x86 and arm (similar tests already existed for x86_64 and aarch64).

The libssp implementation may be located in a separate DLL, and in those cases, the references need to be in a .refptr stub, to avoid needing to touch up code in the text section at runtime (which is supported but inefficient for x86, and unsupported for arm).

There were half a dozen of commits at least on top of this change (so it's not trivial to revert back to working condition, to add more comprehensive tests for the original state), and none of them seem to have an associated phabricator review thread to comment on, so commenting here instead...


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D92738

Files:
  llvm/lib/CodeGen/TargetLoweringBase.cpp
  llvm/test/CodeGen/ARM/win32-ssp.ll
  llvm/test/CodeGen/X86/win32-ssp.ll


Index: llvm/test/CodeGen/X86/win32-ssp.ll
===================================================================
--- llvm/test/CodeGen/X86/win32-ssp.ll
+++ llvm/test/CodeGen/X86/win32-ssp.ll
@@ -1,6 +1,7 @@
 ; RUN: llc -mtriple=x86_64-w64-mingw32        < %s -o - | FileCheck --check-prefix=MINGW %s
 ; RUN: llc -mtriple=x86_64-pc-windows-itanium < %s -o - | FileCheck --check-prefix=MSVC  %s
 ; RUN: llc -mtriple=x86_64-pc-windows-msvc    < %s -o - | FileCheck --check-prefix=MSVC  %s
+; RUN: llc -mtriple=i686-w64-mingw32          < %s -o - | FileCheck --check-prefix=MINGW %s
 
 declare void @llvm.lifetime.start.p0i8(i64, i8* nocapture)
 declare dso_local void @other(i8*)
@@ -9,12 +10,11 @@
 define dso_local void @func() sspstrong {
 entry:
 ; MINGW-LABEL: func:
-; MINGW: mov{{l|q}}  .refptr.__stack_chk_guard(%rip), [[REG:%[a-z]+]]
+; MINGW: mov{{l|q}}  .refptr.[[PREFIX:_?]]__stack_chk_guard{{(\(%rip\))?}}, [[REG:%[a-z]+]]
 ; MINGW: mov{{l|q}}  ([[REG]])
-; MINGW: callq other
+; MINGW: call{{l|q}} [[PREFIX]]other
 ; MINGW: mov{{l|q}}  ([[REG]])
-; MINGW: callq __stack_chk_fail
-; MINGW: .seh_endproc
+; MINGW: call{{l|q}} [[PREFIX]]__stack_chk_fail
 
 ; MSVC-LABEL: func:
 ; MSVC: mov{{l|q}} __security_cookie
Index: llvm/test/CodeGen/ARM/win32-ssp.ll
===================================================================
--- /dev/null
+++ llvm/test/CodeGen/ARM/win32-ssp.ll
@@ -0,0 +1,23 @@
+; RUN: llc -mtriple=thumbv7-w64-mingw32 < %s -o - | FileCheck --check-prefix=MINGW %s
+
+declare void @llvm.lifetime.start.p0i8(i64, i8* nocapture)
+declare dso_local void @other(i8*)
+declare void @llvm.lifetime.end.p0i8(i64, i8* nocapture)
+
+define dso_local void @func() sspstrong {
+entry:
+; MINGW-LABEL: func:
+; MINGW: movw [[REG:r[0-9]+]], :lower16:.refptr.__stack_chk_guard
+; MINGW: movt [[REG]], :upper16:.refptr.__stack_chk_guard
+; MINGW: ldr [[REG2:r[0-9]+]], {{\[}}[[REG]]]
+; MINGW: ldr {{r[0-9]+}}, {{\[}}[[REG2]]]
+; MINGW: bl other
+; MINGW: ldr {{r[0-9]+}}, {{\[}}[[REG2]]]
+; MINGW: bl __stack_chk_fail
+
+  %c = alloca i8, align 1
+  call void @llvm.lifetime.start.p0i8(i64 1, i8* nonnull %c)
+  call void @other(i8* nonnull %c)
+  call void @llvm.lifetime.end.p0i8(i64 1, i8* nonnull %c)
+  ret void
+}
Index: llvm/lib/CodeGen/TargetLoweringBase.cpp
===================================================================
--- llvm/lib/CodeGen/TargetLoweringBase.cpp
+++ llvm/lib/CodeGen/TargetLoweringBase.cpp
@@ -1973,7 +1973,8 @@
     auto *GV = new GlobalVariable(M, Type::getInt8PtrTy(M.getContext()), false,
                                   GlobalVariable::ExternalLinkage, nullptr,
                                   "__stack_chk_guard");
-    if (getTargetMachine().getRelocationModel() == Reloc::Static)
+    if (TM.getRelocationModel() == Reloc::Static &&
+        !TM.getTargetTriple().isWindowsGNUEnvironment())
       GV->setDSOLocal(true);
   }
 }


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