[clang] 2f4eac6 - [clang][ARM] disable frame pointers by default for bare metal ARM targets (#117140)
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cfe-commits at lists.llvm.org
Fri Dec 6 06:05:34 PST 2024
Author: Ties Stuij
Date: 2024-12-06T14:05:30Z
New Revision: 2f4eac62879f9ccf6fda53e4e083e8eed46a9119
URL: https://github.com/llvm/llvm-project/commit/2f4eac62879f9ccf6fda53e4e083e8eed46a9119
DIFF: https://github.com/llvm/llvm-project/commit/2f4eac62879f9ccf6fda53e4e083e8eed46a9119.diff
LOG: [clang][ARM] disable frame pointers by default for bare metal ARM targets (#117140)
because:
- This brings Clang in line with GCC for which this is the default for ARM
- It frees up a register, so performance increase, especially on Thumb/6-M
- It will decrease code size
Added:
Modified:
clang/lib/Driver/ToolChains/Arch/ARM.cpp
clang/lib/Driver/ToolChains/Arch/ARM.h
clang/lib/Driver/ToolChains/BareMetal.cpp
clang/lib/Driver/ToolChains/CommonArgs.cpp
clang/test/Driver/frame-pointer-elim.c
Removed:
################################################################################
diff --git a/clang/lib/Driver/ToolChains/Arch/ARM.cpp b/clang/lib/Driver/ToolChains/Arch/ARM.cpp
index e6ee2317a160cc..b8181ce6dc012a 100644
--- a/clang/lib/Driver/ToolChains/Arch/ARM.cpp
+++ b/clang/lib/Driver/ToolChains/Arch/ARM.cpp
@@ -52,6 +52,26 @@ bool arm::isARMAProfile(const llvm::Triple &Triple) {
return llvm::ARM::parseArchProfile(Arch) == llvm::ARM::ProfileKind::A;
}
+/// Is the triple {arm,armeb,thumb,thumbeb}-none-none-{eabi,eabihf} ?
+bool arm::isARMEABIBareMetal(const llvm::Triple &Triple) {
+ auto arch = Triple.getArch();
+ if (arch != llvm::Triple::arm && arch != llvm::Triple::thumb &&
+ arch != llvm::Triple::armeb && arch != llvm::Triple::thumbeb)
+ return false;
+
+ if (Triple.getVendor() != llvm::Triple::UnknownVendor)
+ return false;
+
+ if (Triple.getOS() != llvm::Triple::UnknownOS)
+ return false;
+
+ if (Triple.getEnvironment() != llvm::Triple::EABI &&
+ Triple.getEnvironment() != llvm::Triple::EABIHF)
+ return false;
+
+ return true;
+}
+
// Get Arch/CPU from args.
void arm::getARMArchCPUFromArgs(const ArgList &Args, llvm::StringRef &Arch,
llvm::StringRef &CPU, bool FromAs) {
diff --git a/clang/lib/Driver/ToolChains/Arch/ARM.h b/clang/lib/Driver/ToolChains/Arch/ARM.h
index fa62ac89e3a138..a23a8793a89e20 100644
--- a/clang/lib/Driver/ToolChains/Arch/ARM.h
+++ b/clang/lib/Driver/ToolChains/Arch/ARM.h
@@ -75,6 +75,7 @@ int getARMSubArchVersionNumber(const llvm::Triple &Triple);
bool isARMMProfile(const llvm::Triple &Triple);
bool isARMAProfile(const llvm::Triple &Triple);
bool isARMBigEndian(const llvm::Triple &Triple, const llvm::opt::ArgList &Args);
+bool isARMEABIBareMetal(const llvm::Triple &Triple);
} // end namespace arm
} // end namespace tools
diff --git a/clang/lib/Driver/ToolChains/BareMetal.cpp b/clang/lib/Driver/ToolChains/BareMetal.cpp
index f9a73f60973e4c..6f550370538b74 100644
--- a/clang/lib/Driver/ToolChains/BareMetal.cpp
+++ b/clang/lib/Driver/ToolChains/BareMetal.cpp
@@ -128,27 +128,6 @@ BareMetal::BareMetal(const Driver &D, const llvm::Triple &Triple,
}
}
-/// Is the triple {arm,armeb,thumb,thumbeb}-none-none-{eabi,eabihf} ?
-static bool isARMBareMetal(const llvm::Triple &Triple) {
- if (Triple.getArch() != llvm::Triple::arm &&
- Triple.getArch() != llvm::Triple::thumb &&
- Triple.getArch() != llvm::Triple::armeb &&
- Triple.getArch() != llvm::Triple::thumbeb)
- return false;
-
- if (Triple.getVendor() != llvm::Triple::UnknownVendor)
- return false;
-
- if (Triple.getOS() != llvm::Triple::UnknownOS)
- return false;
-
- if (Triple.getEnvironment() != llvm::Triple::EABI &&
- Triple.getEnvironment() != llvm::Triple::EABIHF)
- return false;
-
- return true;
-}
-
/// Is the triple {aarch64.aarch64_be}-none-elf?
static bool isAArch64BareMetal(const llvm::Triple &Triple) {
if (Triple.getArch() != llvm::Triple::aarch64 &&
@@ -267,7 +246,7 @@ void BareMetal::findMultilibs(const Driver &D, const llvm::Triple &Triple,
}
bool BareMetal::handlesTarget(const llvm::Triple &Triple) {
- return isARMBareMetal(Triple) || isAArch64BareMetal(Triple) ||
+ return arm::isARMEABIBareMetal(Triple) || isAArch64BareMetal(Triple) ||
isRISCVBareMetal(Triple) || isPPCBareMetal(Triple);
}
@@ -561,7 +540,7 @@ void baremetal::Linker::ConstructJob(Compilation &C, const JobAction &JA,
// The R_ARM_TARGET2 relocation must be treated as R_ARM_REL32 on arm*-*-elf
// and arm*-*-eabi (the default is R_ARM_GOT_PREL, used on arm*-*-linux and
// arm*-*-*bsd).
- if (isARMBareMetal(TC.getTriple()))
+ if (arm::isARMEABIBareMetal(TC.getTriple()))
CmdArgs.push_back("--target2=rel");
CmdArgs.push_back("-o");
diff --git a/clang/lib/Driver/ToolChains/CommonArgs.cpp b/clang/lib/Driver/ToolChains/CommonArgs.cpp
index 8d977149e62485..7d3d7f8f03c491 100644
--- a/clang/lib/Driver/ToolChains/CommonArgs.cpp
+++ b/clang/lib/Driver/ToolChains/CommonArgs.cpp
@@ -19,6 +19,7 @@
#include "Arch/SystemZ.h"
#include "Arch/VE.h"
#include "Arch/X86.h"
+#include "BareMetal.h"
#include "HIPAMD.h"
#include "Hexagon.h"
#include "MSP430.h"
@@ -151,6 +152,9 @@ static bool useFramePointerForTargetByDefault(const llvm::opt::ArgList &Args,
}
}
+ if (arm::isARMEABIBareMetal(Triple))
+ return false;
+
return true;
}
diff --git a/clang/test/Driver/frame-pointer-elim.c b/clang/test/Driver/frame-pointer-elim.c
index cdedcc7ae4c89f..f64ff6efc72610 100644
--- a/clang/test/Driver/frame-pointer-elim.c
+++ b/clang/test/Driver/frame-pointer-elim.c
@@ -162,5 +162,58 @@
// RUN: FileCheck --check-prefix=KEEP-NON-LEAF %s
// RUN: not %clang -### --target=riscv64-linux-android -mbig-endian -O1 -S %s 2>&1 | \
// RUN: FileCheck --check-prefix=KEEP-NON-LEAF %s
+
+// On ARM backend bare metal targets, frame pointer is omitted
+// RUN: %clang -### --target=arm-arm-none-eabi -S %s 2>&1 | \
+// RUN: FileCheck --check-prefix=KEEP-NONE %s
+// RUN: %clang -### --target=arm-arm-none-eabihf -S %s 2>&1 | \
+// RUN: FileCheck --check-prefix=KEEP-NONE %s
+// RUN: %clang -### --target=arm-arm-none-eabi -S -fno-omit-frame-pointer %s 2>&1 | \
+// RUN: FileCheck --check-prefix=KEEP-ALL %s
+// RUN: %clang -### --target=arm-arm-none-eabihf -S -fno-omit-frame-pointer %s 2>&1 | \
+// RUN: FileCheck --check-prefix=KEEP-ALL %s
+// RUN: %clang -### --target=arm-arm-none-eabi -S -O1 %s 2>&1 | \
+// RUN: FileCheck --check-prefix=KEEP-NONE %s
+// RUN: %clang -### --target=arm-arm-none-eabihf -S -O1 %s 2>&1 | \
+// RUN: FileCheck --check-prefix=KEEP-NONE %s
+// RUN: %clang -### --target=arm-arm-none-eabi -S -O1 -fno-omit-frame-pointer %s 2>&1 | \
+// RUN: FileCheck --check-prefix=KEEP-ALL %s
+// RUN: %clang -### --target=arm-arm-none-eabihf -S -O1 -fno-omit-frame-pointer %s 2>&1 | \
+// RUN: FileCheck --check-prefix=KEEP-ALL %s
+// RUN: %clang -### --target=armeb-arm-none-eabi -S %s 2>&1 | \
+// RUN: FileCheck --check-prefix=KEEP-NONE %s
+// RUN: %clang -### --target=thumb-arm-none-eabi -S %s 2>&1 | \
+// RUN: FileCheck --check-prefix=KEEP-NONE %s
+// RUN: %clang -### --target=thumbeb-arm-none-eabi -S %s 2>&1 | \
+// RUN: FileCheck --check-prefix=KEEP-NONE %s
+
+// Check that for Apple bare metal targets, we're keeping frame pointers by default
+// RUN: %clang -### --target=thumbv6m-apple-none-macho -S %s 2>&1 | \
+// RUN: FileCheck --check-prefix=KEEP-ALL %s
+// RUN: %clang -### --target=thumbv6m-apple-none-macho -S -fno-omit-frame-pointer %s 2>&1 | \
+// RUN: FileCheck --check-prefix=KEEP-ALL %s
+// RUN: %clang -### --target=arm-apple-none-macho -S %s 2>&1 | \
+// RUN: FileCheck --check-prefix=KEEP-ALL %s
+// RUN: %clang -### --target=arm-apple-none-macho -S -fno-omit-frame-pointer %s 2>&1 | \
+// RUN: FileCheck --check-prefix=KEEP-ALL %s
+// RUN: %clang -### --target=thumbv6m-apple-none-macho -S -O1 %s 2>&1 | \
+// RUN: FileCheck --check-prefix=KEEP-ALL %s
+// RUN: %clang -### --target=thumbv6m-apple-none-macho -S -O1 -fno-omit-frame-pointer %s 2>&1 | \
+// RUN: FileCheck --check-prefix=KEEP-ALL %s
+// RUN: %clang -### --target=arm-apple-none-macho -S -O1 %s 2>&1 | \
+// RUN: FileCheck --check-prefix=KEEP-ALL %s
+// RUN: %clang -### --target=arm-apple-none-macho -S -O1 -fno-omit-frame-pointer %s 2>&1 | \
+// RUN: FileCheck --check-prefix=KEEP-ALL %s
+
+// AArch64 bare metal targets behave like hosted targets
+// RUN: %clang -### --target=aarch64-none-elf -S %s 2>&1 | \
+// RUN: FileCheck --check-prefix=KEEP-NON-LEAF %s
+// RUN: %clang -### --target=aarch64-none-elf -S -O1 %s 2>&1 | \
+// RUN: FileCheck --check-prefix=KEEP-NON-LEAF %s
+// RUN: %clang -### --target=aarch64-none-elf -S -fno-omit-frame-pointer %s 2>&1 | \
+// RUN: FileCheck --check-prefix=KEEP-NON-LEAF %s
+// RUN: %clang -### --target=aarch64-none-elf -S -O1 -fno-omit-frame-pointer %s 2>&1 | \
+// RUN: FileCheck --check-prefix=KEEP-NON-LEAF %s
+
void f0() {}
void f1() { f0(); }
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