Patch to enable -fPIE and -fstack-protector by default on OpenBSD

[Matthew Dempsky]

On Tue, Jun 04, 2013 at 12:53:56AM -0400, Rafael Esp??ndola wrote:
> needs a testcase.

Done.

I also realized OpenBSD wants -nopie to override the fact that the
linker defaults to emitting PIE, so that's included in the diff below
too.

Lastly, OpenBSD only defaults to -fPIE on alpha, powerpc, and sparc64;
on other architectures, it defaults to -fpie.  But Driver/Tools.cpp
doesn't seem able to represent this cleanly.  I'll look into a
followup patch to improve this, but that shouldn't block this one IMO.


Index: include/clang/Driver/Options.td
===================================================================
--- include/clang/Driver/Options.td	(revision 183062)
+++ include/clang/Driver/Options.td	(working copy)
@@ -1007,6 +1007,7 @@
 def nofixprebinding : Flag<["-"], "nofixprebinding">;
 def nolibc : Flag<["-"], "nolibc">;
 def nomultidefs : Flag<["-"], "nomultidefs">;
+def nopie : Flag<["-"], "nopie">;
 def noprebind : Flag<["-"], "noprebind">;
 def noseglinkedit : Flag<["-"], "noseglinkedit">;
 def nostartfiles : Flag<["-"], "nostartfiles">;
Index: lib/Driver/ToolChains.h
===================================================================
--- lib/Driver/ToolChains.h	(revision 183062)
+++ lib/Driver/ToolChains.h	(working copy)
@@ -427,7 +427,12 @@
 
   virtual bool IsMathErrnoDefault() const { return false; }
   virtual bool IsObjCNonFragileABIDefault() const { return true; }
+  virtual bool isPIEDefault() const { return true; }
 
+  virtual unsigned GetDefaultStackProtectorLevel(bool KernelOrKext) const {
+    return 1;
+  }
+
 protected:
   virtual Tool *buildAssembler() const;
   virtual Tool *buildLinker() const;
Index: lib/Driver/Tools.cpp
===================================================================
--- lib/Driver/Tools.cpp	(revision 183062)
+++ lib/Driver/Tools.cpp	(working copy)
@@ -5165,6 +5165,9 @@
     }
   }
 
+  if (Args.hasArg(options::OPT_nopie))
+    CmdArgs.push_back("-nopie");
+
   if (Output.isFilename()) {
     CmdArgs.push_back("-o");
     CmdArgs.push_back(Output.getFilename());
Index: test/Driver/pic.c
===================================================================
--- test/Driver/pic.c	(revision 183062)
+++ test/Driver/pic.c	(working copy)
@@ -24,6 +24,8 @@
 // CHECK-PIE-LD: "Scrt1.o" "crti.o" "crtbeginS.o"
 // CHECK-PIE-LD: "crtendS.o" "crtn.o"
 //
+// CHECK-NOPIE-LD: "-nopie"
+//
 // CHECK-DYNAMIC-NO-PIC-32: "-mrelocation-model" "dynamic-no-pic"
 // CHECK-DYNAMIC-NO-PIC-32-NOT: "-pic-level"
 // CHECK-DYNAMIC-NO-PIC-32-NOT: "-pie-level"
@@ -197,3 +199,13 @@
 // RUN:   | FileCheck %s --check-prefix=CHECK-NO-PIC
 // RUN: %clang -c %s -target armv7-apple-ios -fapple-kext -miphoneos-version-min=6.0.0 -static -### 2>&1 \
 // RUN:   | FileCheck %s --check-prefix=CHECK-NO-PIC
+//
+// On OpenBSD, PIE is enabled by default, but can be disabled.
+// RUN: %clang -c %s -target i386-pc-openbsd -### 2>&1 \
+// RUN:   | FileCheck %s --check-prefix=CHECK-PIE2
+// RUN: %clang -c %s -target i386-pc-openbsd -fno-pie -### 2>&1 \
+// RUN:   | FileCheck %s --check-prefix=CHECK-NO-PIC
+//
+// On OpenBSD, -nopie needs to be passed through to the linker.
+// RUN: %clang %s -target i386-pc-openbsd -nopie -### 2>&1 \
+// RUN:   | FileCheck %s --check-prefix=CHECK-NOPIE-LD
Index: test/Driver/stack-protector.c
===================================================================
--- test/Driver/stack-protector.c	(revision 183062)
+++ test/Driver/stack-protector.c	(working copy)
@@ -9,3 +9,9 @@
 // RUN: %clang -fstack-protector --param ssp-buffer-size=16 -### %s 2>&1 | FileCheck %s -check-prefix=SSP-BUF
 // SSP-BUF: "-stack-protector" "1"
 // SSP-BUF: "-stack-protector-buffer-size" "16" 
+
+// RUN: %clang -target i386-pc-openbsd -### %s 2>&1 | FileCheck %s -check-prefix=OPENBSD
+// OPENBSD: "-stack-protector" "1"
+
+// RUN: %clang -target i386-pc-openbsd -fno-stack-protector -### %s 2>&1 | FileCheck %s -check-prefix=OPENBSD_OFF
+// OPENBSD_OFF-NOT: "-stack-protector"