[PATCH] D87615: [X86] Fix stack alignment on 32-bit Solaris/x86

[Rainer Orth via Phabricator via llvm-commits]

ro updated this revision to Diff 291831.
ro retitled this revision from "[clang][Driver] Force stack realignment on 32-bit Solaris/x86" to "[X86] Fix stack alignment on 32-bit Solaris/x86".
ro added a comment.
Herald added subscribers: llvm-commits, hiraditya.
Herald added a project: LLVM.

Set `stackAlignment` instead.

Tested on `amd64-pc-solaris2.11`.  However, compared to the `-mstackrealign` version
there's one regression that I still need to investigate:

  UBSan-Standalone-i386 :: TestCases/TypeCheck/vptr.cpp


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D87615/new/

https://reviews.llvm.org/D87615

Files:
  llvm/lib/Target/X86/X86Subtarget.cpp


Index: llvm/lib/Target/X86/X86Subtarget.cpp
===================================================================
--- llvm/lib/Target/X86/X86Subtarget.cpp
+++ llvm/lib/Target/X86/X86Subtarget.cpp
@@ -258,13 +258,16 @@
     report_fatal_error("64-bit code requested on a subtarget that doesn't "
                        "support it!");
 
-  // Stack alignment is 16 bytes on Darwin, Linux, kFreeBSD and Solaris (both
-  // 32 and 64 bit) and for all 64-bit targets.
+  // Stack alignment is 16 bytes on Darwin, Linux, kFreeBSD and for all
+  // 64-bit targets.  On Solaris (32-bit), stack alignment is 4 bytes
+  // following the i386 psABI, while on Illumos it is always 16 bytes.
   if (StackAlignOverride)
     stackAlignment = *StackAlignOverride;
-  else if (isTargetDarwin() || isTargetLinux() || isTargetSolaris() ||
-           isTargetKFreeBSD() || In64BitMode)
+  else if (isTargetDarwin() || isTargetLinux() || isTargetKFreeBSD() ||
+           In64BitMode)
     stackAlignment = Align(16);
+  else if (isTargetSolaris() && !In64BitMode)
+    stackAlignment = Align(4);
 
   // Consume the vector width attribute or apply any target specific limit.
   if (PreferVectorWidthOverride)


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