fix: select medany toolchain and available GDB

tools/doctor.sh

@@ -30,6 +30,27 @@ if [[ -n "$TOOLCHAIN" ]]; then
 fi
 check riscv-gcc "$riscv_gcc" --version
 
+if [[ -n "$riscv_gcc" && -x "$riscv_gcc" ]]; then
+  medany_dir="$(mktemp -d "${TMPDIR:-/tmp}/gps-medany-check.XXXXXXXX")"
+  printf '%s\n' \
+    '#include <stdlib.h>' \
+    'void _start(void) { void *p = malloc(16); free(p); for (;;) {} }' \
+    > "$medany_dir/check.c"
+  if "$riscv_gcc" \
+      -march=rv64imafdc_zicsr_zifencei -mabi=lp64d -mcmodel=medany \
+      -Os -ffreestanding -fno-builtin -static -nostartfiles \
+      -Wl,-Ttext=0x80000000 -Wl,--unresolved-symbols=ignore-all \
+      "$medany_dir/check.c" -Wl,--start-group -lc -lgcc -Wl,--end-group \
+      -o "$medany_dir/check.elf" >/dev/null 2>&1; then
+    printf 'OK       %-10s %s\n' riscv-libc 'medany @ 0x80000000'
+  else
+    printf 'INCOMPAT %-10s %s\n' riscv-libc \
+      'libc is not medany; select RISCV_TOOLCHAIN=/tools/toolchains/rvtc-medany'
+    status=1
+  fi
+  rm -rf "$medany_dir"
+fi
+
 if [[ "$(uname -s)" != Linux || "$(uname -m)" != x86_64 ]]; then
   printf 'WARNING  Kilitli JDK/CIRCT paketleri Linux-x86_64 icindir.\n'
 fi

tools/project.mk

@@ -21,23 +21,32 @@ VIVADO ?= $(lastword $(sort $(wildcard /tools/Xilinx/*/Vivado/bin/vivado) $(shel
 # TOOLCHAIN keeps compatibility with the existing software Makefiles.
 RISCV_TOOLCHAIN ?=
 _RISCV_SEARCH_DIRS := \
+  $(if $(strip $(RISCV_TOOLCHAIN)),$(RISCV_TOOLCHAIN) $(RISCV_TOOLCHAIN)/bin) \
   $(TOOLCHAIN) \
-  $(RISCV_TOOLCHAIN) \
-  $(RISCV_TOOLCHAIN)/bin \
   $(PROJECT_TOOLS_DIR)/riscv/bin \
   /tools/toolchains-medany/bin \
+  /tools/toolchains/rvtc-medany/bin \
   /tools/toolchain/bin \
-  /tools/toolchains/bin \
-  /tools/toolchains/rvtc-medany/bin
+  /tools/toolchains/bin
 _RISCV_GCC := $(firstword \
   $(foreach d,$(_RISCV_SEARCH_DIRS),$(wildcard $(d)/riscv64-unknown-elf-gcc)) \
   $(foreach d,$(_RISCV_SEARCH_DIRS),$(wildcard $(d)/riscv64-none-elf-gcc)) \
   $(shell command -v riscv64-unknown-elf-gcc 2>/dev/null) \
   $(shell command -v riscv64-none-elf-gcc 2>/dev/null))
 
+# An explicit RISCV_TOOLCHAIN is authoritative, including over an old
+# TOOLCHAIN/RISCV_PREFIX inherited from the shell.  Without override, Make's
+# environment-variable semantics leave CROSS pointing at the stale toolchain
+# even though _RISCV_GCC was found in RISCV_TOOLCHAIN.
+ifneq ($(strip $(RISCV_TOOLCHAIN)),)
+override TOOLCHAIN := $(patsubst %/,%,$(dir $(_RISCV_GCC)))
+override RISCV_PREFIX := $(if $(_RISCV_GCC),$(patsubst %-gcc,%-,$(notdir $(_RISCV_GCC))),riscv64-unknown-elf-)
+override CROSS := $(if $(strip $(TOOLCHAIN)),$(TOOLCHAIN)/)$(RISCV_PREFIX)
+else
 TOOLCHAIN ?= $(patsubst %/,%,$(dir $(_RISCV_GCC)))
 RISCV_PREFIX ?= $(if $(_RISCV_GCC),$(patsubst %-gcc,%-,$(notdir $(_RISCV_GCC))),riscv64-unknown-elf-)
 CROSS ?= $(if $(strip $(TOOLCHAIN)),$(TOOLCHAIN)/)$(RISCV_PREFIX)
+endif
 
 # Some compiler-only toolchains (notably rvtc-medany) do not ship GDB.  Keep
 # using the selected compiler toolchain, but fall back to the full local
@@ -45,6 +54,8 @@ CROSS ?= $(if $(strip $(TOOLCHAIN)),$(TOOLCHAIN)/)$(RISCV_PREFIX)
 _RISCV_GDB := $(firstword \
   $(wildcard $(TOOLCHAIN)/$(RISCV_PREFIX)gdb) \
   $(wildcard /tools/toolchains/tc/toolchain/bin/$(RISCV_PREFIX)gdb) \
+  $(wildcard /tools/toolchain/bin/$(RISCV_PREFIX)gdb) \
+  $(lastword $(sort $(wildcard /tools/Xilinx/*/gnu/riscv/lin/bin/$(RISCV_PREFIX)gdb))) \
   $(shell command -v $(RISCV_PREFIX)gdb 2>/dev/null))
 GDB ?= $(if $(_RISCV_GDB),$(_RISCV_GDB),$(CROSS)gdb)