[clang] Fix mtp (PR #130022)
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Thu Mar 6 01:10:25 PST 2025
https://github.com/Zhenhang1213 created https://github.com/llvm/llvm-project/pull/130022
None
>From 0db9830f5d5e29288c87e5935df913b99a040d93 Mon Sep 17 00:00:00 2001
From: Austin <zhenhangwang at huawei.com>
Date: Thu, 27 Feb 2025 00:11:56 +0800
Subject: [PATCH 1/3] [ARM] Introduce -mtp=auto and make it the default
This adds a new value auto to the possible values of the existing -mtp=
clang option which controls how the thread pointer is found. auto means
the same as soft if the target architecture doesn't support a hardware
thread pointer at all; otherwise it means the same as cp15.
This behavior is the default in gcc version 4.1.0 and later. The new
auto option is therefore also the default in clang, so this change
aligns clang with gcc.
Fixes #123864.
---
clang/docs/ReleaseNotes.rst | 4 ++++
clang/include/clang/Driver/Options.td | 2 +-
clang/lib/Driver/ToolChains/Arch/ARM.cpp | 15 +++++++++------
clang/lib/Driver/ToolChains/Arch/ARM.h | 1 +
clang/test/Driver/arm-thread-pointer.c | 6 +++++-
5 files changed, 20 insertions(+), 8 deletions(-)
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 307edf77ebb58..b74feda157ecc 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -122,6 +122,10 @@ Deprecated Compiler Flags
Modified Compiler Flags
-----------------------
+- The ARM AArch32 ``-mtp`` option accepts and defaults to ``auto``, a value of ``auto`` uses the best available method of providing the frame pointer supported by the hardware. This matches
+ the behavior of ``-mtp`` in gcc. This changes the default behavior for ARM targets that provide the ``TPIDRURO`` register as this will be used instead of a call to the ``__aeabi_read_tp``.
+ Programs that use ``__aeabi_read_tp`` but do not use the ``TPIDRURO`` register must use ``-mtp=soft``. Fixes #123864
+
Removed Compiler Flags
-------------------------
diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td
index e521cbf678d93..2bd6076bea5d4 100644
--- a/clang/include/clang/Driver/Options.td
+++ b/clang/include/clang/Driver/Options.td
@@ -4711,7 +4711,7 @@ def mexecute_only : Flag<["-"], "mexecute-only">, Group<m_arm_Features_Group>,
def mno_execute_only : Flag<["-"], "mno-execute-only">, Group<m_arm_Features_Group>,
HelpText<"Allow generation of data access to code sections (ARM only)">;
let Flags = [TargetSpecific] in {
-def mtp_mode_EQ : Joined<["-"], "mtp=">, Group<m_arm_Features_Group>, Values<"soft,cp15,tpidrurw,tpidruro,tpidrprw,el0,el1,el2,el3,tpidr_el0,tpidr_el1,tpidr_el2,tpidr_el3,tpidrro_el0">,
+def mtp_mode_EQ : Joined<["-"], "mtp=">, Group<m_arm_Features_Group>, Values<"soft,cp15,tpidrurw,tpidruro,tpidrprw,el0,el1,el2,el3,tpidr_el0,tpidr_el1,tpidr_el2,tpidr_el3,tpidrro_el0,auto">,
HelpText<"Thread pointer access method. "
"For AArch32: 'soft' uses a function call, or 'tpidrurw', 'tpidruro' or 'tpidrprw' use the three CP15 registers. 'cp15' is an alias for 'tpidruro'. "
"For AArch64: 'tpidr_el0', 'tpidr_el1', 'tpidr_el2', 'tpidr_el3' or 'tpidrro_el0' use the five system registers. 'elN' is an alias for 'tpidr_elN'.">;
diff --git a/clang/lib/Driver/ToolChains/Arch/ARM.cpp b/clang/lib/Driver/ToolChains/Arch/ARM.cpp
index 3aee540d501be..51454de1b9dcc 100644
--- a/clang/lib/Driver/ToolChains/Arch/ARM.cpp
+++ b/clang/lib/Driver/ToolChains/Arch/ARM.cpp
@@ -215,7 +215,8 @@ bool arm::isHardTPSupported(const llvm::Triple &Triple) {
// Select mode for reading thread pointer (-mtp=soft/cp15).
arm::ReadTPMode arm::getReadTPMode(const Driver &D, const ArgList &Args,
const llvm::Triple &Triple, bool ForAS) {
- if (Arg *A = Args.getLastArg(options::OPT_mtp_mode_EQ)) {
+ Arg *A = Args.getLastArg(options::OPT_mtp_mode_EQ);
+ if (A && A->getValue() != StringRef("auto")) {
arm::ReadTPMode ThreadPointer =
llvm::StringSwitch<arm::ReadTPMode>(A->getValue())
.Case("cp15", ReadTPMode::TPIDRURO)
@@ -239,7 +240,7 @@ arm::ReadTPMode arm::getReadTPMode(const Driver &D, const ArgList &Args,
D.Diag(diag::err_drv_invalid_mtp) << A->getAsString(Args);
return ReadTPMode::Invalid;
}
- return ReadTPMode::Soft;
+ return (isHardTPSupported(Triple) ? ReadTPMode::TPIDRURO : ReadTPMode::Soft);
}
void arm::setArchNameInTriple(const Driver &D, const ArgList &Args,
@@ -574,12 +575,14 @@ llvm::ARM::FPUKind arm::getARMTargetFeatures(const Driver &D,
A->ignoreTargetSpecific();
}
- if (getReadTPMode(D, Args, Triple, ForAS) == ReadTPMode::TPIDRURW)
+ arm::ReadTPMode TPMode = getReadTPMode(D, Args, Triple, ForAS);
+
+ if (TPMode == ReadTPMode::TPIDRURW)
Features.push_back("+read-tp-tpidrurw");
- if (getReadTPMode(D, Args, Triple, ForAS) == ReadTPMode::TPIDRURO)
- Features.push_back("+read-tp-tpidruro");
- if (getReadTPMode(D, Args, Triple, ForAS) == ReadTPMode::TPIDRPRW)
+ else if (TPMode == ReadTPMode::TPIDRPRW)
Features.push_back("+read-tp-tpidrprw");
+ else if (TPMode == ReadTPMode::TPIDRURO)
+ Features.push_back("+read-tp-tpidruro");
const Arg *ArchArg = Args.getLastArg(options::OPT_march_EQ);
const Arg *CPUArg = Args.getLastArg(options::OPT_mcpu_EQ);
diff --git a/clang/lib/Driver/ToolChains/Arch/ARM.h b/clang/lib/Driver/ToolChains/Arch/ARM.h
index a23a8793a89e2..622383cf0025d 100644
--- a/clang/lib/Driver/ToolChains/Arch/ARM.h
+++ b/clang/lib/Driver/ToolChains/Arch/ARM.h
@@ -41,6 +41,7 @@ enum class ReadTPMode {
TPIDRURW,
TPIDRURO,
TPIDRPRW,
+ Auto,
};
enum class FloatABI {
diff --git a/clang/test/Driver/arm-thread-pointer.c b/clang/test/Driver/arm-thread-pointer.c
index 5521e1865b276..985c5046f6d26 100644
--- a/clang/test/Driver/arm-thread-pointer.c
+++ b/clang/test/Driver/arm-thread-pointer.c
@@ -42,4 +42,8 @@
// RUN: %clang --target=armv7-linux -### -S %s 2>&1 | \
// RUN: FileCheck -check-prefix=ARMv7_THREAD_POINTER_NON %s
-// ARMv7_THREAD_POINTER_NON-NOT: "-target-feature" "+read-tp-tpidruro"
+// ARMv7_THREAD_POINTER_NON: "-target-feature" "+read-tp-tpidruro"
+
+// RUN: %clang --target=armv7-linux -mtp=auto -### -S %s 2>&1 | \
+// RUN: FileCheck -check-prefix=ARMv7_THREAD_POINTER_Auto %s
+// ARMv7_THREAD_POINTER_Auto: "-target-feature" "+read-tp-tpidruro"
>From a8061a2ce957a51e4f54500bc95ed238496a33fc Mon Sep 17 00:00:00 2001
From: Austin <zhenhangwang at huawei.com>
Date: Thu, 6 Mar 2025 17:04:19 +0800
Subject: [PATCH 2/3] [ARM] Using cp15 while mtp =auto and arch is arm_arch6k
and support thumb2
We follow GCC mtp=auto when arch is arm_arch6k and support thumb2
---
clang/lib/Driver/ToolChains/Arch/ARM.cpp | 13 ++++++++++---
clang/test/Driver/arm-thread-pointer.c | 16 ++++++++++++++++
2 files changed, 26 insertions(+), 3 deletions(-)
diff --git a/clang/lib/Driver/ToolChains/Arch/ARM.cpp b/clang/lib/Driver/ToolChains/Arch/ARM.cpp
index 51454de1b9dcc..b7d5b3a9a882a 100644
--- a/clang/lib/Driver/ToolChains/Arch/ARM.cpp
+++ b/clang/lib/Driver/ToolChains/Arch/ARM.cpp
@@ -208,10 +208,17 @@ bool arm::useAAPCSForMachO(const llvm::Triple &T) {
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);
+ return Triple.isARM() || (Ver >= 7 && AK != llvm::ARM::ArchKind::ARMV8MBaseline);
}
+
+// We follow GCC mtp=auto when arch is arm_arch6k and support thumb2
+bool arm::isHardTPAndThumb2(const llvm::Triple &Triple) {
+ llvm::ARM::ArchKind AK = llvm::ARM::parseArch(Triple.getArchName());
+ return Triple.isARM() && AK >= llvm::ARM::ArchKind::ARMV6K && 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, bool ForAS) {
@@ -240,7 +247,7 @@ arm::ReadTPMode arm::getReadTPMode(const Driver &D, const ArgList &Args,
D.Diag(diag::err_drv_invalid_mtp) << A->getAsString(Args);
return ReadTPMode::Invalid;
}
- return (isHardTPSupported(Triple) ? ReadTPMode::TPIDRURO : ReadTPMode::Soft);
+ return (isHardTPAndThumb2(Triple) ? ReadTPMode::TPIDRURO : ReadTPMode::Soft);
}
void arm::setArchNameInTriple(const Driver &D, const ArgList &Args,
diff --git a/clang/test/Driver/arm-thread-pointer.c b/clang/test/Driver/arm-thread-pointer.c
index 985c5046f6d26..b487a8d83fe34 100644
--- a/clang/test/Driver/arm-thread-pointer.c
+++ b/clang/test/Driver/arm-thread-pointer.c
@@ -47,3 +47,19 @@
// RUN: %clang --target=armv7-linux -mtp=auto -### -S %s 2>&1 | \
// RUN: FileCheck -check-prefix=ARMv7_THREAD_POINTER_Auto %s
// ARMv7_THREAD_POINTER_Auto: "-target-feature" "+read-tp-tpidruro"
+
+// RUN: %clang --target=armv5t-linux -mtp=auto -### -S %s 2>&1 | \
+// RUN: FileCheck -check-prefix=ARMv5t_THREAD_POINTER_Auto %s
+// ARMv5t_THREAD_POINTER_Auto-NOT: "-target-feature" "+read-tp-tpidruro"
+
+// RUN: %clang --target=armv6k-linux -mtp=auto -### -S %s 2>&1 | \
+// RUN: FileCheck -check-prefix=ARMv6k_THREAD_POINTER_Auto %s
+// ARMv6k_THREAD_POINTER_Auto: "-target-feature" "+read-tp-tpidruro"
+
+// RUN: %clang --target=armv6-linux -mtp=auto -### -S %s 2>&1 | \
+// RUN: FileCheck -check-prefix=ARMv6_THREAD_POINTER_Auto %s
+// ARMv6_THREAD_POINTER_Auto-NOT: "-target-feature" "+read-tp-tpidruro"
+
+// RUN: %clang --target=armv6kz-linux -mtp=auto -### -S %s 2>&1 | \
+// RUN: FileCheck -check-prefix=ARMv6kz_THREAD_POINTER_Auto %s
+// ARMv6kz_THREAD_POINTER_Auto: "-target-feature" "+read-tp-tpidruro"
>From 6deb2dc862460a1b853a139f2a904f609b0e3da1 Mon Sep 17 00:00:00 2001
From: Austin <zhenhangwang at huawei.com>
Date: Thu, 6 Mar 2025 17:04:19 +0800
Subject: [PATCH 3/3] [ARM] Using cp15 while mtp =auto and arch is arm_arch6k
and support thumb2
We follow GCC mtp=auto when arch is arm_arch6k and support thumb2
---
clang/lib/Driver/ToolChains/Arch/ARM.cpp | 13 ++++++++++---
clang/lib/Driver/ToolChains/Arch/ARM.h | 1 +
clang/test/Driver/arm-thread-pointer.c | 16 ++++++++++++++++
3 files changed, 27 insertions(+), 3 deletions(-)
diff --git a/clang/lib/Driver/ToolChains/Arch/ARM.cpp b/clang/lib/Driver/ToolChains/Arch/ARM.cpp
index 51454de1b9dcc..b7d5b3a9a882a 100644
--- a/clang/lib/Driver/ToolChains/Arch/ARM.cpp
+++ b/clang/lib/Driver/ToolChains/Arch/ARM.cpp
@@ -208,10 +208,17 @@ bool arm::useAAPCSForMachO(const llvm::Triple &T) {
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);
+ return Triple.isARM() || (Ver >= 7 && AK != llvm::ARM::ArchKind::ARMV8MBaseline);
}
+
+// We follow GCC mtp=auto when arch is arm_arch6k and support thumb2
+bool arm::isHardTPAndThumb2(const llvm::Triple &Triple) {
+ llvm::ARM::ArchKind AK = llvm::ARM::parseArch(Triple.getArchName());
+ return Triple.isARM() && AK >= llvm::ARM::ArchKind::ARMV6K && 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, bool ForAS) {
@@ -240,7 +247,7 @@ arm::ReadTPMode arm::getReadTPMode(const Driver &D, const ArgList &Args,
D.Diag(diag::err_drv_invalid_mtp) << A->getAsString(Args);
return ReadTPMode::Invalid;
}
- return (isHardTPSupported(Triple) ? ReadTPMode::TPIDRURO : ReadTPMode::Soft);
+ return (isHardTPAndThumb2(Triple) ? ReadTPMode::TPIDRURO : ReadTPMode::Soft);
}
void arm::setArchNameInTriple(const Driver &D, const ArgList &Args,
diff --git a/clang/lib/Driver/ToolChains/Arch/ARM.h b/clang/lib/Driver/ToolChains/Arch/ARM.h
index a23a8793a89e2..0641580900fd1 100644
--- a/clang/lib/Driver/ToolChains/Arch/ARM.h
+++ b/clang/lib/Driver/ToolChains/Arch/ARM.h
@@ -57,6 +57,7 @@ FloatABI getARMFloatABI(const Driver &D, const llvm::Triple &Triple,
void setFloatABIInTriple(const Driver &D, const llvm::opt::ArgList &Args,
llvm::Triple &triple);
bool isHardTPSupported(const llvm::Triple &Triple);
+bool isHardTPAndThumb2(const llvm::Triple &Triple);
ReadTPMode getReadTPMode(const Driver &D, const llvm::opt::ArgList &Args,
const llvm::Triple &Triple, bool ForAS);
void setArchNameInTriple(const Driver &D, const llvm::opt::ArgList &Args,
diff --git a/clang/test/Driver/arm-thread-pointer.c b/clang/test/Driver/arm-thread-pointer.c
index 985c5046f6d26..b487a8d83fe34 100644
--- a/clang/test/Driver/arm-thread-pointer.c
+++ b/clang/test/Driver/arm-thread-pointer.c
@@ -47,3 +47,19 @@
// RUN: %clang --target=armv7-linux -mtp=auto -### -S %s 2>&1 | \
// RUN: FileCheck -check-prefix=ARMv7_THREAD_POINTER_Auto %s
// ARMv7_THREAD_POINTER_Auto: "-target-feature" "+read-tp-tpidruro"
+
+// RUN: %clang --target=armv5t-linux -mtp=auto -### -S %s 2>&1 | \
+// RUN: FileCheck -check-prefix=ARMv5t_THREAD_POINTER_Auto %s
+// ARMv5t_THREAD_POINTER_Auto-NOT: "-target-feature" "+read-tp-tpidruro"
+
+// RUN: %clang --target=armv6k-linux -mtp=auto -### -S %s 2>&1 | \
+// RUN: FileCheck -check-prefix=ARMv6k_THREAD_POINTER_Auto %s
+// ARMv6k_THREAD_POINTER_Auto: "-target-feature" "+read-tp-tpidruro"
+
+// RUN: %clang --target=armv6-linux -mtp=auto -### -S %s 2>&1 | \
+// RUN: FileCheck -check-prefix=ARMv6_THREAD_POINTER_Auto %s
+// ARMv6_THREAD_POINTER_Auto-NOT: "-target-feature" "+read-tp-tpidruro"
+
+// RUN: %clang --target=armv6kz-linux -mtp=auto -### -S %s 2>&1 | \
+// RUN: FileCheck -check-prefix=ARMv6kz_THREAD_POINTER_Auto %s
+// ARMv6kz_THREAD_POINTER_Auto: "-target-feature" "+read-tp-tpidruro"
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