llvm-project/clang/test/Driver/frame-pointer-elim.c

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// KEEP-ALL-NOT: warning:
// KEEP-ALL: "-mframe-pointer=all"
// KEEP-NON-LEAF-NOT: warning:
// KEEP-NON-LEAF: "-mframe-pointer=non-leaf"
// KEEP-NONE-NOT: warning:
// KEEP-NONE: "-mframe-pointer=none"
// 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
// fno-omit-frame-pointer -momit-leaf-frame-pointer can be overwritten by
// fomit-frame-pointer later on the command without warning
// RUN: %clang -### -target i386-linux -S -O1 -fno-omit-frame-pointer -momit-leaf-frame-pointer -fomit-frame-pointer %s 2>&1 | \
// RUN: FileCheck --check-prefix=KEEP-NONE %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
// 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=KEEP-NONE %s
// RUN: %clang -### -target x86_64-unknown-cloudabi -S %s 2>&1 | \
// 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=KEEP-NONE %s
// RUN: %clang -### -target x86_64-unknown-netbsd -S %s 2>&1 | \
// 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=KEEP-ALL %s
// RUN: %clang -### -target i386-apple-darwin -S -O1 %s 2>&1 | \
// RUN: FileCheck --check-prefix=KEEP-ALL %s
// RUN: %clang -### -target i386-darwin -S -fomit-frame-pointer %s 2>&1 | \
// RUN: FileCheck --check-prefix=KEEP-NONE %s
// RUN: %clang -### -target i386-darwin -S -momit-leaf-frame-pointer %s 2>&1 | \
// 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
// WARN-OMIT-7S: warning: optimization flag '-fomit-frame-pointer' is not supported for target 'armv7s'
// WARN-OMIT-7S: "-mframe-pointer=all"
// RUN: %clang -### -target armv7k-apple-watchos -fomit-frame-pointer %s 2>&1 | \
// RUN: FileCheck --check-prefix=WARN-OMIT-7K %s
// WARN-OMIT-7K: warning: optimization flag '-fomit-frame-pointer' is not supported for target 'armv7k'
// WARN-OMIT-7K: "-mframe-pointer=all"
// RUN: %clang -### -target armv7s-apple-ios8.0 -momit-leaf-frame-pointer %s 2>&1 | \
// RUN: FileCheck --check-prefix=WARN-OMIT-LEAF-7S %s
// WARN-OMIT-LEAF-7S-NOT: warning: optimization flag '-momit-leaf-frame-pointer' is not supported for target 'armv7s'
// WARN-OMIT-LEAF-7S: "-mframe-pointer=non-leaf"
// On AArch64, PS4, PS5, and VE, default to omitting the frame pointer on leaf
// functions
// RUN: %clang -### -target aarch64 -S %s 2>&1 | \
// RUN: FileCheck --check-prefix=KEEP-NON-LEAF %s
// RUN: %clang -### -target x86_64-scei-ps4 -S %s 2>&1 | \
// RUN: FileCheck --check-prefix=KEEP-NON-LEAF %s
// RUN: %clang -### -target x86_64-scei-ps4 -S -O2 %s 2>&1 | \
// RUN: FileCheck --check-prefix=KEEP-NON-LEAF %s
// RUN: %clang -### -target x86_64-sie-ps5 -S %s 2>&1 | \
// RUN: FileCheck --check-prefix=KEEP-NON-LEAF %s
// RUN: %clang -### -target x86_64-sie-ps5 -S -O2 %s 2>&1 | \
// RUN: FileCheck --check-prefix=KEEP-NON-LEAF %s
// RUN: %clang -### -target aarch64-apple-darwin -arch arm64_32 -S %s 2>&1 | \
// RUN: FileCheck --check-prefix=KEEP-NON-LEAF %s
// RUN: %clang -### -target ve-unknown-linux-gnu -S %s 2>&1 | \
// RUN: FileCheck --check-prefix=KEEP-NON-LEAF %s
// RUN: %clang -### -target powerpc64 -S %s 2>&1 | \
// RUN: FileCheck --check-prefix=KEEP-ALL %s
// RUN: %clang -### -target powerpc64 -S -O1 %s 2>&1 | \
// RUN: FileCheck --check-prefix=KEEP-NONE %s
[Clang][A32/T32][Linux] -O1 implies -fomit-frame-pointer Summary: An upgrade of LLVM for CrOS [0] containing [1] triggered a bunch of errors related to writing to reserved registers for a Linux kernel's arm64 compat vdso (which is a aarch32 image). After a discussion on LKML [2], it was determined that -f{no-}omit-frame-pointer was not being specified. Comparing GCC and Clang [3], it becomes apparent that GCC defaults to omitting the frame pointer implicitly when optimizations are enabled, and Clang does not. ie. setting -O1 (or above) implies -fomit-frame-pointer. Clang was defaulting to -fno-omit-frame-pointer implicitly unless -fomit-frame-pointer was set explicitly. Why this becomes a problem is that the Linux kernel's arm64 compat vdso contains code that uses r7. r7 is used sometimes for the frame pointer (for example, when targeting thumb (-mthumb)). See useR7AsFramePointer() in llvm/llvm-project/llvm/lib/Target/ARM/ARMSubtarget.h. This is mostly for legacy/compatibility reasons, and the 2019 Q4 revision of the ARM AAPCS looks to standardize r11 as the frame pointer for aarch32, though this is not yet implemented in LLVM. Users that are reliant on the implicit value if unspecified when optimizations are enabled should explicitly choose -fomit-frame-pointer (new behavior) or -fno-omit-frame-pointer (old behavior). [0] https://bugs.chromium.org/p/chromium/issues/detail?id=1084372 [1] https://reviews.llvm.org/D76848 [2] https://lore.kernel.org/lkml/20200526173117.155339-1-ndesaulniers@google.com/ [3] https://godbolt.org/z/0oY39t Reviewers: kristof.beyls, psmith, danalbert, srhines, MaskRay, ostannard, efriedma Reviewed By: psmith, danalbert, srhines, MaskRay, efriedma Subscribers: efriedma, olista01, MaskRay, vhscampos, cfe-commits, llvm-commits, manojgupta, llozano, glider, hctim, eugenis, pcc, peter.smith, srhines Tags: #clang, #llvm Differential Revision: https://reviews.llvm.org/D80828
2020-06-03 06:54:09 +08:00
// For AAarch32 (A32, T32) linux targets, default omit frame pointer when
// optimizations are enabled.
// RUN: %clang -### -target arm-linux-gnueabihf- -marm -S %s 2>&1 | \
// RUN: FileCheck --check-prefix=KEEP-ALL %s
// RUN: %clang -### -target arm-linux-gnueabihf- -mthumb -S %s 2>&1 | \
// RUN: FileCheck --check-prefix=KEEP-ALL %s
// RUN: %clang -### -target arm-linux-gnueabihf- -marm -mbig-endian -S %s 2>&1 | \
// RUN: FileCheck --check-prefix=KEEP-ALL %s
// RUN: %clang -### -target arm-linux-gnueabihf- -mthumb -mbig-endian -S %s 2>&1 | \
// RUN: FileCheck --check-prefix=KEEP-ALL %s
// RUN: %clang -### -target arm-linux-gnueabihf- -marm -O1 -S %s 2>&1 | \
// RUN: FileCheck --check-prefix=KEEP-NONE %s
// RUN: %clang -### -target arm-linux-gnueabihf- -mthumb -O1 -S %s 2>&1 | \
// RUN: FileCheck --check-prefix=KEEP-NONE %s
// RUN: %clang -### -target arm-linux-gnueabihf- -marm -mbig-endian -O1 -S %s 2>&1 | \
// RUN: FileCheck --check-prefix=KEEP-NONE %s
// RUN: %clang -### -target arm-linux-gnueabihf- -mthumb -mbig-endian -O1 -S %s 2>&1 | \
// RUN: FileCheck --check-prefix=KEEP-NONE %s
// For Android, keep the framepointers always.
// RUN: %clang -### -target armv7a-linux-androideabi- -marm -O1 -S %s 2>&1 | \
// RUN: FileCheck --check-prefix=KEEP-ALL %s
// RUN: %clang -### -target armv7a-linux-androideabi- -mthumb -O1 -S %s 2>&1 | \
// RUN: FileCheck --check-prefix=KEEP-ALL %s
// RUN: %clang -### -target armv7a-linux-androideabi- -marm -mbig-endian -O1 -S %s 2>&1 | \
// RUN: FileCheck --check-prefix=KEEP-ALL %s
// RUN: %clang -### -target armv7a-linux-androideabi- -mthumb -mbig-endian -O1 -S %s 2>&1 | \
// RUN: FileCheck --check-prefix=KEEP-ALL %s
void f0() {}
void f1() { f0(); }