[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
diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
index 6e2f1f3..bc54845 100644
--- a/clang/lib/Driver/ToolChains/Clang.cpp
+++ b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -501,6 +501,8 @@
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 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 @@
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 @@
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 @@
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 @@
}
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);