r249227 - Driver: follow WoA ABI recommendations

[Saleem Abdulrasool via cfe-commits]

Author: compnerd
Date: Fri Oct  2 22:39:28 2015
New Revision: 249227

URL: http://llvm.org/viewvc/llvm-project?rev=249227&view=rev
Log:
Driver: follow WoA ABI recommendations

The Windows on ARM ABI recommends that FPO be disabled.  This is since the
Windows on ARM ABI uses the FP for fast stack walking.  By paying the slight
cost of the loss of registers, a much faster backtrace is possible by using the
frame pointer since the pdata need not be consulted.  Furthermore, even if pdata
is not available, you can still more easily reconstruct the stack.

Added:
    cfe/trunk/test/Driver/woa-fp.c
Modified:
    cfe/trunk/lib/Driver/Tools.cpp

Modified: cfe/trunk/lib/Driver/Tools.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Driver/Tools.cpp?rev=249227&r1=249226&r2=249227&view=diff
==============================================================================
--- cfe/trunk/lib/Driver/Tools.cpp (original)
+++ cfe/trunk/lib/Driver/Tools.cpp Fri Oct  2 22:39:28 2015
@@ -2655,6 +2655,10 @@ static bool shouldUseFramePointerForTarg
     switch (Triple.getArch()) {
     case llvm::Triple::x86:
       return !areOptimizationsEnabled(Args);
+    case llvm::Triple::arm:
+    case llvm::Triple::thumb:
+      // Windows on ARM builds with FPO disabled to aid fast stack walking
+      return true;
     default:
       // All other supported Windows ISAs use xdata unwind information, so frame
       // pointers are not generally useful.

Added: cfe/trunk/test/Driver/woa-fp.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Driver/woa-fp.c?rev=249227&view=auto
==============================================================================
--- cfe/trunk/test/Driver/woa-fp.c (added)
+++ cfe/trunk/test/Driver/woa-fp.c Fri Oct  2 22:39:28 2015
@@ -0,0 +1,40 @@
+// RUN: %clang -target armv7-windows-msvc -### -S %s -O0 -o /dev/null 2>&1 | FileCheck %s -check-prefix CHECK-DEFAULT
+// RUN: %clang -target armv7-windows-msvc -### -S %s -O1 -o /dev/null 2>&1 | FileCheck %s -check-prefix CHECK-DEFAULT
+// RUN: %clang -target armv7-windows-msvc -### -S %s -O2 -o /dev/null 2>&1 | FileCheck %s -check-prefix CHECK-DEFAULT
+// RUN: %clang -target armv7-windows-msvc -### -S %s -O3 -o /dev/null 2>&1 | FileCheck %s -check-prefix CHECK-DEFAULT
+// RUN: %clang -target armv7-windows-msvc -### -S %s -Os -o /dev/null 2>&1 | FileCheck %s -check-prefix CHECK-DEFAULT
+
+// RUN: %clang -target armv7-windows-itanium -### -S %s -O0 -o /dev/null 2>&1 | FileCheck %s -check-prefix CHECK-DEFAULT
+// RUN: %clang -target armv7-windows-itanium -### -S %s -O1 -o /dev/null 2>&1 | FileCheck %s -check-prefix CHECK-DEFAULT
+// RUN: %clang -target armv7-windows-itanium -### -S %s -O2 -o /dev/null 2>&1 | FileCheck %s -check-prefix CHECK-DEFAULT
+// RUN: %clang -target armv7-windows-itanium -### -S %s -O3 -o /dev/null 2>&1 | FileCheck %s -check-prefix CHECK-DEFAULT
+// RUN: %clang -target armv7-windows-itanium -### -S %s -Os -o /dev/null 2>&1 | FileCheck %s -check-prefix CHECK-DEFAULT
+
+// RUN: %clang -target armv7-windows-msvc -fomit-frame-pointer -### -S %s -O0 -o /dev/null 2>&1 | FileCheck %s -check-prefix CHECK-FPO
+// RUN: %clang -target armv7-windows-msvc -fomit-frame-pointer -### -S %s -O1 -o /dev/null 2>&1 | FileCheck %s -check-prefix CHECK-FPO
+// RUN: %clang -target armv7-windows-msvc -fomit-frame-pointer -### -S %s -O2 -o /dev/null 2>&1 | FileCheck %s -check-prefix CHECK-FPO
+// RUN: %clang -target armv7-windows-msvc -fomit-frame-pointer -### -S %s -O3 -o /dev/null 2>&1 | FileCheck %s -check-prefix CHECK-FPO
+// RUN: %clang -target armv7-windows-msvc -fomit-frame-pointer -### -S %s -Os -o /dev/null 2>&1 | FileCheck %s -check-prefix CHECK-FPO
+
+// RUN: %clang -target armv7-windows-itanium -fomit-frame-pointer -### -S %s -O0 -o /dev/null 2>&1 | FileCheck %s -check-prefix CHECK-FPO
+// RUN: %clang -target armv7-windows-itanium -fomit-frame-pointer -### -S %s -O1 -o /dev/null 2>&1 | FileCheck %s -check-prefix CHECK-FPO
+// RUN: %clang -target armv7-windows-itanium -fomit-frame-pointer -### -S %s -O2 -o /dev/null 2>&1 | FileCheck %s -check-prefix CHECK-FPO
+// RUN: %clang -target armv7-windows-itanium -fomit-frame-pointer -### -S %s -O3 -o /dev/null 2>&1 | FileCheck %s -check-prefix CHECK-FPO
+// RUN: %clang -target armv7-windows-itanium -fomit-frame-pointer -### -S %s -Os -o /dev/null 2>&1 | FileCheck %s -check-prefix CHECK-FPO
+
+// RUN: %clang -target armv7-windows-msvc -fno-omit-frame-pointer -### -S %s -O0 -o /dev/null 2>&1 | FileCheck %s -check-prefix CHECK-NO-FPO
+// RUN: %clang -target armv7-windows-msvc -fno-omit-frame-pointer -### -S %s -O1 -o /dev/null 2>&1 | FileCheck %s -check-prefix CHECK-NO-FPO
+// RUN: %clang -target armv7-windows-msvc -fno-omit-frame-pointer -### -S %s -O2 -o /dev/null 2>&1 | FileCheck %s -check-prefix CHECK-NO-FPO
+// RUN: %clang -target armv7-windows-msvc -fno-omit-frame-pointer -### -S %s -O3 -o /dev/null 2>&1 | FileCheck %s -check-prefix CHECK-NO-FPO
+// RUN: %clang -target armv7-windows-msvc -fno-omit-frame-pointer -### -S %s -Os -o /dev/null 2>&1 | FileCheck %s -check-prefix CHECK-NO-FPO
+
+// RUN: %clang -target armv7-windows-itanium -fno-omit-frame-pointer -### -S %s -O0 -o /dev/null 2>&1 | FileCheck %s -check-prefix CHECK-NO-FPO
+// RUN: %clang -target armv7-windows-itanium -fno-omit-frame-pointer -### -S %s -O1 -o /dev/null 2>&1 | FileCheck %s -check-prefix CHECK-NO-FPO
+// RUN: %clang -target armv7-windows-itanium -fno-omit-frame-pointer -### -S %s -O2 -o /dev/null 2>&1 | FileCheck %s -check-prefix CHECK-NO-FPO
+// RUN: %clang -target armv7-windows-itanium -fno-omit-frame-pointer -### -S %s -O3 -o /dev/null 2>&1 | FileCheck %s -check-prefix CHECK-NO-FPO
+// RUN: %clang -target armv7-windows-itanium -fno-omit-frame-pointer -### -S %s -Os -o /dev/null 2>&1 | FileCheck %s -check-prefix CHECK-NO-FPO
+
+// CHECK-DEFAULT: "-mdisable-fp-elim"
+// CHECK-FPO-NOT: "-mdisable-fp-elim"
+// CHECK-NO-FPO: "-mdisable-fp-elim"
+