[Driver] Refactor interaction between -f(no-)?omit-frame-pointer and -m(no-)?omit-leaf-frame-pointer

Use a tri-state enum to represent shouldUseFramePointer() and
shouldUseLeafFramePointer().

This simplifies the logic and fixes PR9825:
  -fno-omit-frame-pointer doesn't imply -mno-omit-leaf-frame-pointer.

and PR24003:
  /Oy- /O2 should not omit leaf frame pointer: this matches MSVC x86-32.
  (/Oy- is a no-op on MSVC x86-64.)

and:
  when CC1 option -mdisable-fp-elim if absent, -momit-leaf-frame-pointer
  can also be omitted.

The new behavior matches GCC:
  -fomit-frame-pointer wins over -mno-omit-leaf-frame-pointer
  -fno-omit-frame-pointer loses out to -momit-leaf-frame-pointer

The behavior makes lots of sense. We have 4 states:

- 00) leaf retained, non-leaf retained
- 01) leaf retained, non-leaf omitted  (this is invalid)
- 10) leaf omitted, non-leaf retained  (what -momit-leaf-frame-pointer was designed for)
- 11) leaf omitted, non-leaf omitted

"omit" options taking precedence over "no-omit" options is the only way
to make 3 valid states representable with -f(no-)?omit-frame-pointer and
-m(no-)?omit-leaf-pointer.

Reviewed By: ychen

Differential Revision: https://reviews.llvm.org/D64294

llvm-svn: 365860

5 files changed, 85 insertions, 69 deletions

diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
index 6e2f1f302c2..bc548453859 100644
--- a/clang/lib/Driver/ToolChains/Clang.cpp
+++ b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -501,6 +501,8 @@ static codegenoptions::DebugInfoKind DebugLevelToInfoKind(const Arg &A) {
   return codegenoptions::LimitedDebugInfo;
 }
 
+enum class FramePointerKind { None, NonLeaf, All };
+
 static bool mustUseNonLeafFramePointerForTarget(const llvm::Triple &Triple) {
   switch (Triple.getArch()){
   default:
@@ -515,6 +517,9 @@ static bool mustUseNonLeafFramePointerForTarget(const llvm::Triple &Triple) {
 
 static bool useFramePointerForTargetByDefault(const ArgList &Args,
                                               const llvm::Triple &Triple) {
+  if (Args.hasArg(options::OPT_pg))
+    return true;
+
   switch (Triple.getArch()) {
   case llvm::Triple::xcore:
   case llvm::Triple::wasm32:
@@ -574,32 +579,22 @@ static bool useFramePointerForTargetByDefault(const ArgList &Args,
   return true;
 }
 
-static bool shouldUseFramePointer(const ArgList &Args,
-                                  const llvm::Triple &Triple) {
-  if (Arg *A = Args.getLastArg(options::OPT_fno_omit_frame_pointer,
-                               options::OPT_fomit_frame_pointer))
-    return A->getOption().matches(options::OPT_fno_omit_frame_pointer) ||
-           mustUseNonLeafFramePointerForTarget(Triple);
-
-  if (Args.hasArg(options::OPT_pg))
-    return true;
-
-  return useFramePointerForTargetByDefault(Args, Triple);
-}
-
-static bool shouldUseLeafFramePointer(const ArgList &Args,
-                                      const llvm::Triple &Triple) {
-  if (Arg *A = Args.getLastArg(options::OPT_mno_omit_leaf_frame_pointer,
-                               options::OPT_momit_leaf_frame_pointer))
-    return A->getOption().matches(options::OPT_mno_omit_leaf_frame_pointer);
-
-  if (Args.hasArg(options::OPT_pg))
-    return true;
-
-  if (Triple.isPS4CPU())
-    return false;
-
-  return useFramePointerForTargetByDefault(Args, Triple);
+static FramePointerKind getFramePointerKind(const ArgList &Args,
+                                            const llvm::Triple &Triple) {
+  Arg *A = Args.getLastArg(options::OPT_fomit_frame_pointer,
+                           options::OPT_fno_omit_frame_pointer);
+  bool OmitFP = A && A->getOption().matches(options::OPT_fomit_frame_pointer);
+  bool NoOmitFP =
+      A && A->getOption().matches(options::OPT_fno_omit_frame_pointer);
+  if (NoOmitFP || mustUseNonLeafFramePointerForTarget(Triple) ||
+      (!OmitFP && useFramePointerForTargetByDefault(Args, Triple))) {
+    if (Args.hasFlag(options::OPT_momit_leaf_frame_pointer,
+                     options::OPT_mno_omit_leaf_frame_pointer,
+                     Triple.isPS4CPU()))
+      return FramePointerKind::NonLeaf;
+    return FramePointerKind::All;
+  }
+  return FramePointerKind::None;
 }
 
 /// Add a CC1 option to specify the debug compilation directory.
@@ -3960,8 +3955,12 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
   if (Args.hasFlag(options::OPT_mrtd, options::OPT_mno_rtd, false))
     CmdArgs.push_back("-fdefault-calling-conv=stdcall");
 
-  if (shouldUseFramePointer(Args, RawTriple))
+  FramePointerKind FPKeepKind = getFramePointerKind(Args, RawTriple);
+  if (FPKeepKind != FramePointerKind::None) {
     CmdArgs.push_back("-mdisable-fp-elim");
+    if (FPKeepKind == FramePointerKind::NonLeaf)
+      CmdArgs.push_back("-momit-leaf-frame-pointer");
+  }
   if (!Args.hasFlag(options::OPT_fzero_initialized_in_bss,
                     options::OPT_fno_zero_initialized_in_bss))
     CmdArgs.push_back("-mno-zero-initialized-in-bss");
@@ -4146,9 +4145,6 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
     CmdArgs.push_back(A->getValue());
   }
 
-  if (!shouldUseLeafFramePointer(Args, RawTriple))
-    CmdArgs.push_back("-momit-leaf-frame-pointer");
-
   // Explicitly error on some things we know we don't support and can't just
   // ignore.
   if (!Args.hasArg(options::OPT_fallow_unsupported)) {
@@ -5503,7 +5499,7 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
   }
 
   if (Arg *A = Args.getLastArg(options::OPT_pg))
-    if (!shouldUseFramePointer(Args, Triple))
+    if (FPKeepKind == FramePointerKind::None)
       D.Diag(diag::err_drv_argument_not_allowed_with) << "-fomit-frame-pointer"
                                                       << A->getAsString(Args);
 
diff --git a/clang/test/Driver/cl-options.c b/clang/test/Driver/cl-options.c
index 04aa08a5576..51a98e53509 100644
--- a/clang/test/Driver/cl-options.c
+++ b/clang/test/Driver/cl-options.c
@@ -161,28 +161,28 @@
 // RUN: %clang_cl /Os --target=i686-pc-windows-msvc -### -- %s 2>&1 | FileCheck -check-prefix=Os %s
 // RUN: %clang_cl /Os --target=x86_64-pc-windows-msvc -### -- %s 2>&1 | FileCheck -check-prefix=Os %s
 // Os-NOT: -mdisable-fp-elim
-// Os: -momit-leaf-frame-pointer
+// Os-NOT: -momit-leaf-frame-pointer
 // Os: -Os
 
 // RUN: %clang_cl /Ot --target=i686-pc-windows-msvc -### -- %s 2>&1 | FileCheck -check-prefix=Ot %s
 // RUN: %clang_cl /Ot --target=x86_64-pc-windows-msvc -### -- %s 2>&1 | FileCheck -check-prefix=Ot %s
 // Ot-NOT: -mdisable-fp-elim
-// Ot: -momit-leaf-frame-pointer
+// Ot-NOT: -momit-leaf-frame-pointer
 // Ot: -O2
 
 // RUN: %clang_cl /Ox --target=i686-pc-windows-msvc -### -- %s 2>&1 | FileCheck -check-prefix=Ox %s
 // RUN: %clang_cl /Ox --target=x86_64-pc-windows-msvc -### -- %s 2>&1 | FileCheck -check-prefix=Ox %s
 // Ox-NOT: -mdisable-fp-elim
-// Ox: -momit-leaf-frame-pointer
+// Ox-NOT: -momit-leaf-frame-pointer
 // Ox: -O2
 
 // RUN: %clang_cl --target=i686-pc-win32 /O2sy- -### -- %s 2>&1 | FileCheck -check-prefix=PR24003 %s
 // PR24003: -mdisable-fp-elim
-// PR24003: -momit-leaf-frame-pointer
+// PR24003-NOT: -momit-leaf-frame-pointer
 // PR24003: -Os
 
 // RUN: %clang_cl --target=i686-pc-win32 -Werror /Oy- /O2 -### -- %s 2>&1 | FileCheck -check-prefix=Oy_2 %s
-// Oy_2: -momit-leaf-frame-pointer
+// Oy_2-NOT: -momit-leaf-frame-pointer
 // Oy_2: -O2
 
 // RUN: %clang_cl --target=aarch64-pc-windows-msvc -Werror /Oy- /O2 -### -- %s 2>&1 | FileCheck -check-prefix=Oy_aarch64 %s
diff --git a/clang/test/Driver/clang_f_opts.c b/clang/test/Driver/clang_f_opts.c
index d3d80fdec41..17feaab26ab 100644
--- a/clang/test/Driver/clang_f_opts.c
+++ b/clang/test/Driver/clang_f_opts.c
@@ -548,11 +548,6 @@
 // CHECK-NO-NULL-POINTER-CHECKS: "-fno-delete-null-pointer-checks"
 // CHECK-NULL-POINTER-CHECKS-NOT: "-fno-delete-null-pointer-checks"
 
-// RUN: %clang -### -S -fomit-frame-pointer -pg %s 2>&1 | FileCheck -check-prefix=CHECK-NO-MIX-OMIT-FP-PG %s
-// RUN: %clang -### -S -fomit-frame-pointer -fno-omit-frame-pointer -pg %s 2>&1 | FileCheck -check-prefix=CHECK-MIX-NO-OMIT-FP-PG %s
-// CHECK-NO-MIX-OMIT-FP-PG: '-fomit-frame-pointer' not allowed with '-pg'
-// CHECK-MIX-NO-OMIT-FP-PG-NOT: '-fomit-frame-pointer' not allowed with '-pg'
-
 // RUN: %clang -### -S -target x86_64-unknown-linux -frecord-gcc-switches %s 2>&1 | FileCheck -check-prefix=CHECK-RECORD-GCC-SWITCHES %s
 // RUN: %clang -### -S -target x86_64-unknown-linux -fno-record-gcc-switches %s 2>&1 | FileCheck -check-prefix=CHECK-NO-RECORD-GCC-SWITCHES %s
 // RUN: %clang -### -S -target x86_64-unknown-linux -fno-record-gcc-switches -frecord-gcc-switches %s 2>&1 | FileCheck -check-prefix=CHECK-RECORD-GCC-SWITCHES %s
diff --git a/clang/test/Driver/frame-pointer-elim.c b/clang/test/Driver/frame-pointer-elim.c
index 6fcd3eb75ae..3e6df2aaf2e 100644
--- a/clang/test/Driver/frame-pointer-elim.c
+++ b/clang/test/Driver/frame-pointer-elim.c
@@ -1,48 +1,74 @@
-// For these next two tests when optimized we should omit the leaf frame
-// pointer, for unoptimized we should have a leaf frame pointer.
-// RUN: %clang -### -target i386-pc-linux-gnu -S -O1 %s 2>&1 | \
-// RUN:   FileCheck --check-prefix=LINUX-OPT %s
-// LINUX-OPT: "-momit-leaf-frame-pointer"
+// KEEP-ALL: "-mdisable-fp-elim"
+// KEEP-ALL-NOT: "-momit-leaf-frame-pointer"
 
-// RUN: %clang -### -target i386-pc-linux-gnu -S %s 2>&1 | \
-// RUN:   FileCheck --check-prefix=LINUX %s
-// LINUX-NOT: "-momit-leaf-frame-pointer"
+// KEEP-NON-LEAF: "-mdisable-fp-elim"
+// KEEP-NON-LEAF: "-momit-leaf-frame-pointer"
+
+// KEEP-NONE-NOT: "-mdisable-fp-elim"
+// KEEP-NONE-NOT: "-momit-leaf-frame-pointer"
+
+// On Linux x86, omit frame pointer when optimization is enabled.
+// RUN: %clang -### -target i386-linux -S -fomit-frame-pointer %s 2>&1 | \
+// RUN:   FileCheck --check-prefix=KEEP-NONE %s
+// RUN: %clang -### -target i386-linux -S -O1 %s 2>&1 | \
+// RUN:   FileCheck --check-prefix=KEEP-NONE %s
+
+// -fno-omit-frame-pointer or -pg disables frame pointer omission.
+// RUN: %clang -### -target i386-linux -S %s 2>&1 | \
+// RUN:   FileCheck --check-prefix=KEEP-ALL %s
+// RUN: %clang -### -target i386-linux -S -O1 -fno-omit-frame-pointer %s 2>&1 | \
+// RUN:   FileCheck --check-prefix=KEEP-ALL %s
+// RUN: %clang -### -target i386-linux -S -O1 -pg %s 2>&1 | \
+// RUN:   FileCheck --check-prefix=KEEP-ALL %s
+
+// -momit-leaf-frame-pointer omits leaf frame pointer.
+// -fno-omit-frame-pointer loses out to -momit-leaf-frame-pointer.
+// RUN: %clang -### -target i386 -S -momit-leaf-frame-pointer %s 2>&1 | \
+// RUN:   FileCheck --check-prefix=KEEP-NON-LEAF %s
+// RUN: %clang -### -target i386-linux -S -O1 -fno-omit-frame-pointer -momit-leaf-frame-pointer %s 2>&1 | \
+// RUN:   FileCheck --check-prefix=KEEP-NON-LEAF %s
+// RUN: %clang -### -target i386-linux -S -O1 -momit-leaf-frame-pointer %s 2>&1 | \
+// RUN:   FileCheck --check-prefix=KEEP-NONE %s
+
+// Explicit or default -fomit-frame-pointer wins over -mno-omit-leaf-frame-pointer.
+// RUN: %clang -### -target i386 -S %s -fomit-frame-pointer -mno-omit-leaf-frame-pointer 2>&1 | \
+// RUN:   FileCheck --check-prefix=KEEP-NONE %s
+// RUN: %clang -### -target i386-linux -S %s -O1 -mno-omit-leaf-frame-pointer 2>&1 | \
+// RUN:   FileCheck --check-prefix=KEEP-NONE %s
+
+// -pg -fomit-frame-pointer => error.
+// RUN: %clang -### -S -fomit-frame-pointer -pg %s 2>&1 | FileCheck -check-prefix=CHECK-NO-MIX-OMIT-FP-PG %s
+// RUN: %clang -### -S -fomit-frame-pointer -fno-omit-frame-pointer -pg %s 2>&1 | FileCheck -check-prefix=CHECK-MIX-NO-OMIT-FP-PG %s
+// CHECK-NO-MIX-OMIT-FP-PG: '-fomit-frame-pointer' not allowed with '-pg'
+// CHECK-MIX-NO-OMIT-FP-PG-NOT: '-fomit-frame-pointer' not allowed with '-pg'
 
 // CloudABI follows the same rules as Linux.
 // RUN: %clang -### -target x86_64-unknown-cloudabi -S -O1 %s 2>&1 | \
-// RUN:   FileCheck --check-prefix=CLOUDABI-OPT %s
-// CLOUDABI-OPT: "-momit-leaf-frame-pointer"
+// RUN:   FileCheck --check-prefix=KEEP-NONE %s
 
 // RUN: %clang -### -target x86_64-unknown-cloudabi -S %s 2>&1 | \
-// RUN:   FileCheck --check-prefix=CLOUDABI %s
-// CLOUDABI-NOT: "-momit-leaf-frame-pointer"
+// RUN:   FileCheck --check-prefix=KEEP-ALL %s
 
 // NetBSD follows the same rules as Linux.
 // RUN: %clang -### -target x86_64-unknown-netbsd -S -O1 %s 2>&1 | \
-// RUN:   FileCheck --check-prefix=NETBSD-OPT %s
-// NETBSD-OPT: "-momit-leaf-frame-pointer"
+// RUN:   FileCheck --check-prefix=KEEP-NONE %s
 
 // RUN: %clang -### -target x86_64-unknown-netbsd -S %s 2>&1 | \
-// RUN:   FileCheck --check-prefix=NETBSD %s
-// NETBSD-NOT: "-momit-leaf-frame-pointer"
+// RUN:   FileCheck --check-prefix=KEEP-ALL %s
 
 // Darwin disables omitting the leaf frame pointer even under optimization
 // unless the command lines are given.
 // RUN: %clang -### -target i386-apple-darwin -S %s 2>&1 | \
-// RUN:   FileCheck --check-prefix=DARWIN %s
-// DARWIN: "-mdisable-fp-elim"
+// RUN:   FileCheck --check-prefix=KEEP-ALL %s
 
 // RUN: %clang -### -target i386-apple-darwin -S -O1 %s 2>&1 | \
-// RUN:   FileCheck --check-prefix=DARWIN-OPT %s
-// DARWIN-OPT-NOT: "-momit-leaf-frame-pointer"
+// RUN:   FileCheck --check-prefix=KEEP-ALL %s
 
 // RUN: %clang -### -target i386-darwin -S -fomit-frame-pointer %s 2>&1 | \
-// RUN:   FileCheck --check-prefix=OMIT_ALL %s
-// OMIT_ALL-NOT: "-mdisable-fp-elim"
+// RUN:   FileCheck --check-prefix=KEEP-NONE %s
 
 // RUN: %clang -### -target i386-darwin -S -momit-leaf-frame-pointer %s 2>&1 | \
-// RUN:   FileCheck --check-prefix=OMIT_LEAF %s
-// OMIT_LEAF: "-momit-leaf-frame-pointer"
+// RUN:   FileCheck --check-prefix=KEEP-NON-LEAF %s
 
 // RUN: %clang -### -target armv7s-apple-ios -fomit-frame-pointer %s 2>&1 | \
 // RUN:   FileCheck --check-prefix=WARN-OMIT-7S %s
@@ -63,11 +89,10 @@
 // WARN-OMIT-LEAF-7S: "-momit-leaf-frame-pointer"
 
 // On the PS4, we default to omitting the frame pointer on leaf functions
-// (OMIT_LEAF check line is above)
 // RUN: %clang -### -target x86_64-scei-ps4 -S %s 2>&1 | \
-// RUN:   FileCheck --check-prefix=OMIT_LEAF %s
+// RUN:   FileCheck --check-prefix=KEEP-NON-LEAF %s
 // RUN: %clang -### -target x86_64-scei-ps4 -S -O2 %s 2>&1 | \
-// RUN:   FileCheck --check-prefix=OMIT_LEAF %s
+// RUN:   FileCheck --check-prefix=KEEP-NON-LEAF %s
 
 void f0() {}
 void f1() { f0(); }
diff --git a/clang/test/Driver/xcore-opts.c b/clang/test/Driver/xcore-opts.c
index 9300085724c..abbc88e1036 100644
--- a/clang/test/Driver/xcore-opts.c
+++ b/clang/test/Driver/xcore-opts.c
@@ -4,8 +4,8 @@
 // RUN: %clang -target xcore %s -g0 -### -o %t.o 2>&1 | FileCheck -check-prefix CHECK-G0 %s
 
 // CHECK: "-nostdsysteminc"
-// CHECK: "-momit-leaf-frame-pointer"
 // CHECK-NOT: "-mdisable-fp-elim"
+// CHECK-NOT: "-momit-leaf-frame-pointer"
 // CHECK: "-fno-signed-char"
 // CHECK: "-fno-use-cxa-atexit"
 // CHECK-NOT: "-fcxx-exceptions"