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-rw-r--r--clang/docs/ReleaseNotes.rst9
-rw-r--r--clang/lib/Driver/ToolChains/Arch/RISCV.cpp139
-rw-r--r--clang/lib/Driver/ToolChains/Arch/RISCV.h2
-rw-r--r--clang/lib/Driver/ToolChains/Gnu.cpp8
-rw-r--r--clang/test/Driver/riscv-abi.c8
-rw-r--r--clang/test/Driver/riscv-gnutools.c45
6 files changed, 182 insertions, 29 deletions
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 1139116ed10..aa0d88db1c9 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -223,6 +223,15 @@ ABI Changes in Clang
element. Clang now matches the gcc behavior on Linux and NetBSD. You can
switch back to old API behavior with flag: -fclang-abi-compat=9.0.
+- RISC-V now chooses a default ``-march=`` and ``-mabi=`` to match (in almost
+ all cases) the GCC defaults. On baremetal targets, where neither ``-march=``
+ nor ``-mabi=`` are specified, Clang now differs from GCC by defaulting to
+ ``-march=rv32imac -mabi=ilp32`` or ``-march=rv64imac -mabi=lp64`` depending on
+ the architecture in the target triple. These do not always match the defaults
+ in Clang 9. We strongly suggest that you explicitly pass `-march=` and
+ `-mabi=` when compiling for RISC-V, due to how extensible this architecture
+ is.
+
OpenMP Support in Clang
-----------------------
diff --git a/clang/lib/Driver/ToolChains/Arch/RISCV.cpp b/clang/lib/Driver/ToolChains/Arch/RISCV.cpp
index a26f723a507..8c343b8693f 100644
--- a/clang/lib/Driver/ToolChains/Arch/RISCV.cpp
+++ b/clang/lib/Driver/ToolChains/Arch/RISCV.cpp
@@ -357,14 +357,9 @@ static bool getArchFeatures(const Driver &D, StringRef MArch,
void riscv::getRISCVTargetFeatures(const Driver &D, const llvm::Triple &Triple,
const ArgList &Args,
std::vector<StringRef> &Features) {
- llvm::Optional<StringRef> MArch;
- if (const Arg *A = Args.getLastArg(options::OPT_march_EQ))
- MArch = A->getValue();
- else if (Triple.getOS() == llvm::Triple::Linux)
- // RISC-V Linux defaults to rv{32,64}gc.
- MArch = Triple.getArch() == llvm::Triple::riscv32 ? "rv32gc" : "rv64gc";
+ StringRef MArch = getRISCVArch(Args, Triple);
- if (MArch.hasValue() && !getArchFeatures(D, *MArch, Features, Args))
+ if (!getArchFeatures(D, MArch, Features, Args))
return;
// Handle features corresponding to "-ffixed-X" options
@@ -455,12 +450,132 @@ StringRef riscv::getRISCVABI(const ArgList &Args, const llvm::Triple &Triple) {
Triple.getArch() == llvm::Triple::riscv64) &&
"Unexpected triple");
+ // GCC's logic around choosing a default `-mabi=` is complex. If GCC is not
+ // configured using `--with-abi=`, then the logic for the default choice is
+ // defined in config.gcc. This function is based on the logic in GCC 9.2.0. We
+ // deviate from GCC's default only on baremetal targets (UnknownOS) where
+ // neither `-march` nor `-mabi` is specified.
+ //
+ // The logic uses the following, in order:
+ // 1. Explicit choices using `--with-abi=`
+ // 2. A default based on `--with-arch=`, if provided
+ // 3. A default based on the target triple's arch
+ //
+ // The logic in config.gcc is a little circular but it is not inconsistent.
+ //
+ // Clang does not have `--with-arch=` or `--with-abi=`, so we use `-march=`
+ // and `-mabi=` respectively instead.
+
+ // 1. If `-mabi=` is specified, use it.
if (const Arg *A = Args.getLastArg(options::OPT_mabi_EQ))
return A->getValue();
- // RISC-V Linux defaults to ilp32d/lp64d
- if (Triple.getOS() == llvm::Triple::Linux)
- return Triple.getArch() == llvm::Triple::riscv32 ? "ilp32d" : "lp64d";
- else
- return Triple.getArch() == llvm::Triple::riscv32 ? "ilp32" : "lp64";
+ // 2. Choose a default based on `-march=`
+ //
+ // rv32g | rv32*d -> ilp32d
+ // rv32e -> ilp32e
+ // rv32* -> ilp32
+ // rv64g | rv64*d -> lp64d
+ // rv64* -> lp64
+ if (const Arg *A = Args.getLastArg(options::OPT_march_EQ)) {
+ StringRef MArch = A->getValue();
+
+ if (MArch.startswith_lower("rv32")) {
+ // FIXME: parse `March` to find `D` extension properly
+ if (MArch.substr(4).contains_lower("d") ||
+ MArch.startswith_lower("rv32g"))
+ return "ilp32d";
+ else if (MArch.startswith_lower("rv32e"))
+ return "ilp32e";
+ else
+ return "ilp32";
+ } else if (MArch.startswith_lower("rv64")) {
+ // FIXME: parse `March` to find `D` extension properly
+ if (MArch.substr(4).contains_lower("d") ||
+ MArch.startswith_lower("rv64g"))
+ return "lp64d";
+ else
+ return "lp64";
+ }
+ }
+
+ // 3. Choose a default based on the triple
+ //
+ // We deviate from GCC's defaults here:
+ // - On `riscv{XLEN}-unknown-elf` we use the integer calling convention only.
+ // - On all other OSs we use the double floating point calling convention.
+ if (Triple.getArch() == llvm::Triple::riscv32) {
+ if (Triple.getOS() == llvm::Triple::UnknownOS)
+ return "ilp32";
+ else
+ return "ilp32d";
+ } else {
+ if (Triple.getOS() == llvm::Triple::UnknownOS)
+ return "lp64";
+ else
+ return "lp64d";
+ }
+}
+
+StringRef riscv::getRISCVArch(const llvm::opt::ArgList &Args,
+ const llvm::Triple &Triple) {
+ assert((Triple.getArch() == llvm::Triple::riscv32 ||
+ Triple.getArch() == llvm::Triple::riscv64) &&
+ "Unexpected triple");
+
+ // GCC's logic around choosing a default `-march=` is complex. If GCC is not
+ // configured using `--with-arch=`, then the logic for the default choice is
+ // defined in config.gcc. This function is based on the logic in GCC 9.2.0. We
+ // deviate from GCC's default only on baremetal targets (UnknownOS) where
+ // neither `-march` nor `-mabi` is specified.
+ //
+ // The logic uses the following, in order:
+ // 1. Explicit choices using `--with-arch=`
+ // 2. A default based on `--with-abi=`, if provided
+ // 3. A default based on the target triple's arch
+ //
+ // The logic in config.gcc is a little circular but it is not inconsistent.
+ //
+ // Clang does not have `--with-arch=` or `--with-abi=`, so we use `-march=`
+ // and `-mabi=` respectively instead.
+ //
+ // Clang does not yet support MULTILIB_REUSE, so we use `rv{XLEN}imafdc`
+ // instead of `rv{XLEN}gc` though they are (currently) equivalent.
+
+ // 1. If `-march=` is specified, use it.
+ if (const Arg *A = Args.getLastArg(options::OPT_march_EQ))
+ return A->getValue();
+
+ // 2. Choose a default based on `-mabi=`
+ //
+ // ilp32e -> rv32e
+ // ilp32 | ilp32f | ilp32d -> rv32imafdc
+ // lp64 | lp64f | lp64d -> rv64imafdc
+ if (const Arg *A = Args.getLastArg(options::OPT_mabi_EQ)) {
+ StringRef MABI = A->getValue();
+
+ if (MABI.equals_lower("ilp32e"))
+ return "rv32e";
+ else if (MABI.startswith_lower("ilp32"))
+ return "rv32imafdc";
+ else if (MABI.startswith_lower("lp64"))
+ return "rv64imafdc";
+ }
+
+ // 3. Choose a default based on the triple
+ //
+ // We deviate from GCC's defaults here:
+ // - On `riscv{XLEN}-unknown-elf` we default to `rv{XLEN}imac`
+ // - On all other OSs we use `rv{XLEN}imafdc` (equivalent to `rv{XLEN}gc`)
+ if (Triple.getArch() == llvm::Triple::riscv32) {
+ if (Triple.getOS() == llvm::Triple::UnknownOS)
+ return "rv32imac";
+ else
+ return "rv32imafdc";
+ } else {
+ if (Triple.getOS() == llvm::Triple::UnknownOS)
+ return "rv64imac";
+ else
+ return "rv64imafdc";
+ }
}
diff --git a/clang/lib/Driver/ToolChains/Arch/RISCV.h b/clang/lib/Driver/ToolChains/Arch/RISCV.h
index 10eaf3c897b..d4a519cdab3 100644
--- a/clang/lib/Driver/ToolChains/Arch/RISCV.h
+++ b/clang/lib/Driver/ToolChains/Arch/RISCV.h
@@ -24,6 +24,8 @@ void getRISCVTargetFeatures(const Driver &D, const llvm::Triple &Triple,
std::vector<llvm::StringRef> &Features);
StringRef getRISCVABI(const llvm::opt::ArgList &Args,
const llvm::Triple &Triple);
+StringRef getRISCVArch(const llvm::opt::ArgList &Args,
+ const llvm::Triple &Triple);
} // end namespace riscv
} // namespace tools
} // end namespace driver
diff --git a/clang/lib/Driver/ToolChains/Gnu.cpp b/clang/lib/Driver/ToolChains/Gnu.cpp
index 6a0c756031d..2dd3450dd1b 100644
--- a/clang/lib/Driver/ToolChains/Gnu.cpp
+++ b/clang/lib/Driver/ToolChains/Gnu.cpp
@@ -709,11 +709,9 @@ void tools::gnutools::Assembler::ConstructJob(Compilation &C,
StringRef ABIName = riscv::getRISCVABI(Args, getToolChain().getTriple());
CmdArgs.push_back("-mabi");
CmdArgs.push_back(ABIName.data());
- if (const Arg *A = Args.getLastArg(options::OPT_march_EQ)) {
- StringRef MArch = A->getValue();
- CmdArgs.push_back("-march");
- CmdArgs.push_back(MArch.data());
- }
+ StringRef MArchName = riscv::getRISCVArch(Args, getToolChain().getTriple());
+ CmdArgs.push_back("-march");
+ CmdArgs.push_back(MArchName.data());
break;
}
case llvm::Triple::sparc:
diff --git a/clang/test/Driver/riscv-abi.c b/clang/test/Driver/riscv-abi.c
index 1a4c7ed477b..ef3913ee3c4 100644
--- a/clang/test/Driver/riscv-abi.c
+++ b/clang/test/Driver/riscv-abi.c
@@ -16,6 +16,10 @@
// RUN: %clang -target riscv32-unknown-elf %s -### -o %t.o -march=rv32ifd -mabi=ilp32d 2>&1 \
// RUN: | FileCheck -check-prefix=CHECK-ILP32D %s
+// RUN: %clang -target riscv32-unknown-linux-gnu %s -### -o %t.o 2>&1 \
+// RUN: | FileCheck -check-prefix=CHECK-ILP32D %s
+// RUN: %clang -target riscv32-unknown-linux-gnu -x assembler %s -### -o %t.o 2>&1 \
+// RUN: | FileCheck -check-prefix=CHECK-ILP32D %s
// CHECK-ILP32D: "-target-abi" "ilp32d"
@@ -42,6 +46,10 @@
// RUN: %clang -target riscv64-unknown-elf %s -### -o %t.o -march=rv64d -mabi=lp64d 2>&1 \
// RUN: | FileCheck -check-prefix=CHECK-LP64D %s
+// RUN: %clang -target riscv64-unknown-linux-gnu %s -### -o %t.o 2>&1 \
+// RUN: | FileCheck -check-prefix=CHECK-LP64D %s
+// RUN: %clang -target riscv64-unknown-linux-gnu -x assembler %s -### -o %t.o 2>&1 \
+// RUN: | FileCheck -check-prefix=CHECK-LP64D %s
// CHECK-LP64D: "-target-abi" "lp64d"
diff --git a/clang/test/Driver/riscv-gnutools.c b/clang/test/Driver/riscv-gnutools.c
index afcb5052aa3..b5ea737ba78 100644
--- a/clang/test/Driver/riscv-gnutools.c
+++ b/clang/test/Driver/riscv-gnutools.c
@@ -1,19 +1,40 @@
// Check gnutools are invoked with propagated values for -mabi and -march.
+//
+// This test also checks the default -march/-mabi for certain targets.
-// RUN: %clang -target riscv32 -fno-integrated-as %s -### -c \
-// RUN: 2>&1 | FileCheck -check-prefix=MABI-ILP32 %s
+// 32-bit checks
-// RUN: %clang -target riscv32 -fno-integrated-as -march=rv32g %s -### -c \
-// RUN: 2>&1 | FileCheck -check-prefix=MABI-ILP32-MARCH-G %s
+// Check default on riscv32-unknown-elf
+// RUN: %clang -target riscv32-unknown-elf -fno-integrated-as %s -### -c \
+// RUN: 2>&1 | FileCheck -check-prefix=CHECK-RV32IMAC-ILP32 %s
-// RUN: %clang -target riscv64 -fno-integrated-as %s -### -c \
-// RUN: 2>&1 | FileCheck -check-prefix=MABI-ILP64 %s
+// Check default on riscv32-unknown-linux-gnu
+// RUN: %clang -target riscv32-unknown-linux-gnu -fno-integrated-as %s -### -c \
+// RUN: 2>&1 | FileCheck -check-prefix=CHECK-RV32IMAFDC-ILP32D %s
-// RUN: %clang -target riscv64 -fno-integrated-as -march=rv64g %s -### -c \
-// RUN: 2>&1 | FileCheck -check-prefix=MABI-ILP64-MARCH-G %s
+// Check default when -march=rv32g specified
+// RUN: %clang -target riscv32 -fno-integrated-as %s -### -c -march=rv32g \
+// RUN: 2>&1 | FileCheck -check-prefix=CHECK-RV32G-ILP32D %s
-// MABI-ILP32: "{{.*}}as{{(.exe)?}}" "-mabi" "ilp32"
-// MABI-ILP32-MARCH-G: "{{.*}}as{{(.exe)?}}" "-mabi" "ilp32" "-march" "rv32g"
+// CHECK-RV32IMAC-ILP32: "{{.*}}as{{(.exe)?}}" "-mabi" "ilp32" "-march" "rv32imac"
+// CHECK-RV32IMAFDC-ILP32D: "{{.*}}as{{(.exe)?}}" "-mabi" "ilp32d" "-march" "rv32imafdc"
+// CHECK-RV32G-ILP32D: "{{.*}}as{{(.exe)?}}" "-mabi" "ilp32d" "-march" "rv32g"
-// MABI-ILP64: "{{.*}}as{{(.exe)?}}" "-mabi" "lp64"
-// MABI-ILP64-MARCH-G: "{{.*}}as{{(.exe)?}}" "-mabi" "lp64" "-march" "rv64g"
+
+// 64-bit checks
+
+// Check default on riscv64-unknown-elf
+// RUN: %clang -target riscv64-unknown-elf -fno-integrated-as %s -### -c \
+// RUN: 2>&1 | FileCheck -check-prefix=CHECK-RV64IMAC-LP64 %s
+
+// Check default on riscv64-unknown-linux-gnu
+// RUN: %clang -target riscv64-unknown-linux-gnu -fno-integrated-as %s -### -c \
+// RUN: 2>&1 | FileCheck -check-prefix=CHECK-RV64IMAFDC-LP64D %s
+
+// Check default when -march=rv64g specified
+// RUN: %clang -target riscv64 -fno-integrated-as %s -### -c -march=rv64g \
+// RUN: 2>&1 | FileCheck -check-prefix=CHECK-RV64G-LP64D %s
+
+// CHECK-RV64IMAC-LP64: "{{.*}}as{{(.exe)?}}" "-mabi" "lp64" "-march" "rv64imac"
+// CHECK-RV64IMAFDC-LP64D: "{{.*}}as{{(.exe)?}}" "-mabi" "lp64d" "-march" "rv64imafdc"
+// CHECK-RV64G-LP64D: "{{.*}}as{{(.exe)?}}" "-mabi" "lp64d" "-march" "rv64g"
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