Compiling C++ code to a Rocket chip RTL simulator - riscv

Question

I'm trying to compile a C++ hello-world (using the standard C++ library) to a verilator simulation of the Rocket chip.
I'm also using the Chipyard 1.6.2 environment to facilitate the process.
The compilation steps I'm using are the following:
#!/bin/bash -e
export COMMON="/root/chipyard/toolchains/esp-tools/riscv-tests/benchmarks/common"
export RV_ENV="/root/chipyard/toolchains/esp-tools/riscv-tests/env"
export STARTFILES_DIR="/root/chipyard/esp-tools-install/lib/gcc/riscv64-unknown-elf/9.2.0"
# define GCC start files to link
export GCC_STARTFILES="\
${STARTFILES_DIR}/crtbegin.o \
${STARTFILES_DIR}/crtend.o
"
# define GCC flags for compilation
export FLAGS="\
-I${COMMON} \
-I${RV_ENV} \
-mcmodel=medany \
-static \
-std=gnu99 \
-g \
-Og \
-ffast-math \
-fno-common \
-fno-builtin-printf \
-fno-tree-loop-distribute-patterns \
-march=rv64gcxhwacha \
-static \
-nostartfiles \
-lm \
-lgcc \
-T ${COMMON}/test.ld \
"
# create cpp hello world
cat << EOF > hello.cpp
#include <iostream>
int main() {
std::cout << "Hello World!\n";
return 0;
}
EOF
# generate object files
riscv64-unknown-elf-gcc ${FLAGS} -c -o crt.o ${COMMON}/crt.S
riscv64-unknown-elf-gcc ${FLAGS} -c -o syscalls.o ${COMMON}/syscalls.c
riscv64-unknown-elf-g++ ${FLAGS} -c -o hello.o hello.cpp
# link object files
riscv64-unknown-elf-g++ ${FLAGS} \
-o hello-cpp.riscv hello.o crt.o syscalls.o ${GCC_STARTFILES}
# run simulation
/root/chipyard/sims/verilator/simulator-chipyard-RocketConfig hello-cpp.riscv
Unfortunately, the simulation gets stuck without printing anything:
root#chipyard:~/smr-gemmini/dev# /root/chipyard/sims/verilator/simulator-chipyard-RocketConfig hello-cpp.riscv
This emulator compiled with JTAG Remote Bitbang client. To enable, use +jtag_rbb_enable=1.
Listening on port 43881
[UART] UART0 is here (stdin/stdout).
While the expected result would be:
root#chipyard:~/smr-gemmini/dev# /root/chipyard/sims/verilator/simulator-chipyard-RocketConfig hello-cpp.riscv
This emulator compiled with JTAG Remote Bitbang client. To enable, use +jtag_rbb_enable=1.
Listening on port 44319
[UART] UART0 is here (stdin/stdout).
Hello World!
A couple of observations:
I've noted that replacing #include <iostream> and std::cout by #include <cstdio> and printf, the script above works.
I've also tried running the simulation with GDB/OpenOCD and the simulation never reached the breakpoint placed in the main function.
I'm guessing that I'm not linking the proper entry and C++ libraries files but I was unable to find a solution for this issue.
Is there a known process for compiling C++ to Rocket chip?