[clang] 9f95bc7 - [clang][ARM] relax -mtp=cp15 for non-thumb cases
Nick Desaulniers via cfe-commits
cfe-commits at lists.llvm.org
Fri Dec 3 14:21:35 PST 2021
Author: Nick Desaulniers
Date: 2021-12-03T14:00:00-08:00
New Revision: 9f95bc7dc18390199553cf2ea3bfcdc6a95717ef
URL: https://github.com/llvm/llvm-project/commit/9f95bc7dc18390199553cf2ea3bfcdc6a95717ef
DIFF: https://github.com/llvm/llvm-project/commit/9f95bc7dc18390199553cf2ea3bfcdc6a95717ef.diff
LOG: [clang][ARM] relax -mtp=cp15 for non-thumb cases
Building -march=armv6k Linux kernels with -mtp=cp15 fails to
compile:
error: hardware TLS register is not supported for the arm
sub-architecture
@ardb found docs for ARM1176JZF-S (ARMv6K) that reference hard thread
pointer.
Relax our ARMv6 check for cases where we're targeting ARM via -marm (vs
Thumb1 via -mthumb). This more closely matches the KConfig requirements
for where we plan to use these (ie. ARMv6K, ARMv7 (arm or thumb2)).
As @peter.smith mentions:
on armv5 we can write the instruction to read/write to CP15 C13 with
the ThreadID opcode. However on no armv5 implementation will the CP15
C13 have a Thread ID register. The GCC intent seems to be whether the
instruction is encodable rather than check what the CPU supports.
Link: https://github.com/ClangBuiltLinux/linux/issues/1502
Link: https://developer.arm.com/documentation/ddi0301/h/system-control-coprocessor/system-control-processor-registers/c13--thread-and-process-id-registers
Reviewed By: ardb, peter.smith
Differential Revision: https://reviews.llvm.org/D114116
Added:
Modified:
clang/lib/Driver/ToolChains/Arch/ARM.cpp
clang/lib/Driver/ToolChains/Arch/ARM.h
clang/test/Driver/clang-translation.c
Removed:
################################################################################
diff --git a/clang/lib/Driver/ToolChains/Arch/ARM.cpp b/clang/lib/Driver/ToolChains/Arch/ARM.cpp
index 21c091e1a0ba4..8d5c64d975502 100644
--- a/clang/lib/Driver/ToolChains/Arch/ARM.cpp
+++ b/clang/lib/Driver/ToolChains/Arch/ARM.cpp
@@ -147,6 +147,16 @@ bool arm::useAAPCSForMachO(const llvm::Triple &T) {
T.getOS() == llvm::Triple::UnknownOS || isARMMProfile(T);
}
+// We follow GCC and support when the backend has support for the MRC/MCR
+// instructions that are used to set the hard thread pointer ("CP15 C13
+// Thread id").
+bool arm::isHardTPSupported(const llvm::Triple &Triple) {
+ int Ver = getARMSubArchVersionNumber(Triple);
+ llvm::ARM::ArchKind AK = llvm::ARM::parseArch(Triple.getArchName());
+ return Triple.isARM() || AK == llvm::ARM::ArchKind::ARMV6T2 ||
+ (Ver >= 7 && AK != llvm::ARM::ArchKind::ARMV8MBaseline);
+}
+
// Select mode for reading thread pointer (-mtp=soft/cp15).
arm::ReadTPMode arm::getReadTPMode(const Driver &D, const ArgList &Args,
const llvm::Triple &Triple) {
@@ -156,10 +166,7 @@ arm::ReadTPMode arm::getReadTPMode(const Driver &D, const ArgList &Args,
.Case("cp15", ReadTPMode::Cp15)
.Case("soft", ReadTPMode::Soft)
.Default(ReadTPMode::Invalid);
- if (ThreadPointer == ReadTPMode::Cp15 &&
- getARMSubArchVersionNumber(Triple) < 7 &&
- llvm::ARM::parseArch(Triple.getArchName()) !=
- llvm::ARM::ArchKind::ARMV6T2) {
+ if (ThreadPointer == ReadTPMode::Cp15 && !isHardTPSupported(Triple)) {
D.Diag(diag::err_target_unsupported_tp_hard) << Triple.getArchName();
return ReadTPMode::Invalid;
}
@@ -430,7 +437,6 @@ void arm::getARMTargetFeatures(const Driver &D, const llvm::Triple &Triple,
bool KernelOrKext =
Args.hasArg(options::OPT_mkernel, options::OPT_fapple_kext);
arm::FloatABI ABI = arm::getARMFloatABI(D, Triple, Args);
- arm::ReadTPMode ThreadPointer = arm::getReadTPMode(D, Args, Triple);
llvm::Optional<std::pair<const Arg *, StringRef>> WaCPU, WaFPU, WaHDiv,
WaArch;
@@ -482,7 +488,7 @@ void arm::getARMTargetFeatures(const Driver &D, const llvm::Triple &Triple,
}
}
- if (ThreadPointer == arm::ReadTPMode::Cp15)
+ if (getReadTPMode(D, Args, Triple) == ReadTPMode::Cp15)
Features.push_back("+read-tp-hard");
const Arg *ArchArg = Args.getLastArg(options::OPT_march_EQ);
diff --git a/clang/lib/Driver/ToolChains/Arch/ARM.h b/clang/lib/Driver/ToolChains/Arch/ARM.h
index b6fd68fbb9c62..fc5b8c87bef9d 100644
--- a/clang/lib/Driver/ToolChains/Arch/ARM.h
+++ b/clang/lib/Driver/ToolChains/Arch/ARM.h
@@ -53,6 +53,7 @@ FloatABI getARMFloatABI(const Driver &D, const llvm::Triple &Triple,
const llvm::opt::ArgList &Args);
void setFloatABIInTriple(const Driver &D, const llvm::opt::ArgList &Args,
llvm::Triple &triple);
+bool isHardTPSupported(const llvm::Triple &Triple);
ReadTPMode getReadTPMode(const Driver &D, const llvm::opt::ArgList &Args,
const llvm::Triple &Triple);
void setArchNameInTriple(const Driver &D, const llvm::opt::ArgList &Args,
diff --git a/clang/test/Driver/clang-translation.c b/clang/test/Driver/clang-translation.c
index 230ea8e302024..32dd43b8352f9 100644
--- a/clang/test/Driver/clang-translation.c
+++ b/clang/test/Driver/clang-translation.c
@@ -115,16 +115,22 @@
// ARMv7_THREAD_POINTER-HARD: "-target-feature" "+read-tp-hard"
// RUN: %clang -target armv6t2-linux -mtp=cp15 -### -S %s 2>&1 | \
-// RUN: FileCheck -check-prefix=ARMv6T2_THREAD_POINTER-HARD %s
-// ARMv6T2_THREAD_POINTER-HARD: "-target-feature" "+read-tp-hard"
-
+// RUN: FileCheck -check-prefix=ARM_THREAD_POINTER-HARD %s
+// RUN: %clang -target thumbv6t2-linux -mtp=cp15 -### -S %s 2>&1 | \
+// RUN: FileCheck -check-prefix=ARM_THREAD_POINTER-HARD %s
+// RUN: %clang -target armv6k-linux -mtp=cp15 -### -S %s 2>&1 | \
+// RUN: FileCheck -check-prefix=ARM_THREAD_POINTER-HARD %s
+// RUN: %clang -target armv6-linux -mtp=cp15 -### -S %s 2>&1 | \
+// RUN: FileCheck -check-prefix=ARM_THREAD_POINTER-HARD %s
// RUN: %clang -target armv5t-linux -mtp=cp15 -### -S %s 2>&1 | \
-// RUN: FileCheck -check-prefix=ARMv5_THREAD_POINTER_UNSUPP %s
-// ARMv5_THREAD_POINTER_UNSUPP: hardware TLS register is not supported for the armv5 sub-architecture
-
-// RUN: %clang -target thumbv6-linux -mtp=cp15 -### -S %s 2>&1 | \
-// RUN: FileCheck -check-prefix=ARMv6_THREAD_POINTER_UNSUPP %s
-// ARMv6_THREAD_POINTER_UNSUPP: hardware TLS register is not supported for the armv6 sub-architecture
+// RUN: FileCheck -check-prefix=ARM_THREAD_POINTER-HARD %s
+// ARM_THREAD_POINTER-HARD: "-target-feature" "+read-tp-hard"
+
+// RUN: %clang -target armv6-linux -mthumb -mtp=cp15 -### -S %s 2>&1 | \
+// RUN: FileCheck -check-prefix=THUMBv6_THREAD_POINTER_UNSUPP %s
+// RUN: %clang -target thumbv6-linux -mthumb -mtp=cp15 -### -S %s 2>&1 | \
+// RUN: FileCheck -check-prefix=THUMBv6_THREAD_POINTER_UNSUPP %s
+// THUMBv6_THREAD_POINTER_UNSUPP: hardware TLS register is not supported for the thumbv6 sub-architecture
// RUN: %clang -target armv7-linux -mtp=soft -### -S %s 2>&1 | \
// RUN: FileCheck -check-prefix=ARMv7_THREAD_POINTER_SOFT %s
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