From 1488d23f96a4d120bf5ec9064256a4df3bfe6c89 Mon Sep 17 00:00:00 2001
From: Nick Gasson <nick@nickg.me.uk>
Date: Sun, 18 Feb 2024 18:06:00 +0000
Subject: [PATCH] Use --without-system-cc to disable AOT compilation

---
 .github/workflows/build-test.yml |  4 ++--
 configure.ac                     | 32 ++++++++++++++++++--------------
 src/cgen.c                       |  8 ++++++--
 src/nvc.c                        | 14 +++++++++-----
 4 files changed, 35 insertions(+), 23 deletions(-)

diff --git a/.github/workflows/build-test.yml b/.github/workflows/build-test.yml
index e38af2e4..9dfb91dc 100644
--- a/.github/workflows/build-test.yml
+++ b/.github/workflows/build-test.yml
@@ -485,11 +485,11 @@ jobs:
         run: |
           echo $PATH
           export PATH=$PATH:/c/Program\ Files\ \(x86\)/WiX\ Toolset\ v3.11/bin
-          which candle
           mkdir build
           cd build
           bash ../configure --enable-static-llvm --enable-tcl \
-            --enable-verilog --enable-gui CFLAGS="-O2" --prefix=`pwd`/installdir
+            --enable-verilog --enable-gui CFLAGS="-O2" \
+            --prefix=`pwd`/installdir --without-system-cc
       - name: Build
         run: make -C build
       - name: Install
diff --git a/configure.ac b/configure.ac
index 0d19c9b5..f488fbec 100644
--- a/configure.ac
+++ b/configure.ac
@@ -360,7 +360,7 @@ if test -n "$linker_path"; then
 fi
 
 # CC may constain unwanted -std=... option.
-cc_bare="$(which ${CC%% *})"
+cc_bare=${CC%% *}
 
 AC_ARG_WITH([system-cc],
             [AS_HELP_STRING([--with-system-cc=PATH],
@@ -368,21 +368,25 @@ AC_ARG_WITH([system-cc],
             [system_cc="$withval"],
             [system_cc="$cc_bare"])
 
-AC_MSG_CHECKING([if $system_cc executable exists])
-AS_IF([test -x $system_cc],
-      [AC_MSG_RESULT([yes])],
-      [AC_MSG_RESULT([no])
-       AC_PATH_PROG([system_cc], ["$system_cc"],
-                    [AC_MSG_ERROR([system C compiler $system_cc not found])])])
+if test x$system_cc != xno; then
+  AC_MSG_CHECKING([if $system_cc executable exists])
+  AS_IF([test -x $system_cc],
+        [AC_MSG_RESULT([yes])],
+        [AC_MSG_RESULT([no])
+         AC_PATH_PROG([system_cc], ["$system_cc"],
+                      [AC_MSG_ERROR([system C compiler $system_cc not found])])])
 
-case $host_os in
-  *cygwin*|msys*|mingw32*)
-    # Do not hard-code full path on Windows
-    system_cc="$(basename $system_cc)"
-    ;;
-esac
+  case $host_os in
+    *cygwin*|msys*|mingw32*)
+      # Do not hard-code full path on Windows
+      system_cc="$(basename $system_cc)"
+      ;;
+  esac
 
-AC_DEFINE_UNQUOTED([SYSTEM_CC], ["$system_cc"], [System compiler])
+  AC_DEFINE_UNQUOTED([SYSTEM_CC], ["$system_cc"], [System compiler])
+else
+  AC_DEFINE_UNQUOTED([BOOTSTRAP_CC], ["$cc_bare"], [Bootstrap compiler])
+fi
 
 case $host_os in
   *cygwin*|msys*|mingw32*)
diff --git a/src/cgen.c b/src/cgen.c
index 2797122a..5058c2d9 100644
--- a/src/cgen.c
+++ b/src/cgen.c
@@ -166,11 +166,15 @@ static void cgen_link_arg(const char *fmt, ...)
 
 static void cgen_linker_setup(void)
 {
-#ifdef LINKER_PATH
+#if defined LINKER_PATH
    cgen_link_arg("%s", LINKER_PATH);
    cgen_link_arg("--eh-frame-hdr");
-#else
+#elif defined SYSTEM_CC
    cgen_link_arg("%s", SYSTEM_CC);
+#elif defined BOOTSTRAP_CC
+   cgen_link_arg("%s", BOOTSTRAP_CC);
+#else
+   fatal_trace("configured without external C compiler or linker");
 #endif
 
 #if defined __APPLE__
diff --git a/src/nvc.c b/src/nvc.c
index ac0f670c..86a36006 100644
--- a/src/nvc.c
+++ b/src/nvc.c
@@ -56,6 +56,12 @@
 #define GIT_SHA_ONLY(x)
 #endif
 
+#if !defined HAVE_LLVM || !defined SYSTEM_CC
+#define DEFAULT_JIT true
+#else
+#define DEFAULT_JIT false
+#endif
+
 typedef struct {
    jit_t           *jit;
    unit_registry_t *registry;
@@ -364,7 +370,7 @@ static int elaborate(int argc, char **argv, cmd_state_t *state)
       { 0, 0, 0, 0 }
    };
 
-   bool use_jit = false, no_save = false;
+   bool use_jit = DEFAULT_JIT, no_save = false;
    cover_mask_t cover_mask = 0;
    char *cover_spec_file = NULL;
    int cover_array_limit = 0;
@@ -471,8 +477,6 @@ static int elaborate(int argc, char **argv, cmd_state_t *state)
    if (error_count() > 0)
       return EXIT_FAILURE;
 
-   const bool aot_codegen = !use_jit NOT_LLVM_ONLY(&& false);
-
    char *pack_name LOCAL = xasprintf("_%s.pack", istr(top_level));
    char *dll_name LOCAL = xasprintf("_%s." DLL_EXT, istr(tree_ident(top)));
 
@@ -486,7 +490,7 @@ static int elaborate(int argc, char **argv, cmd_state_t *state)
       progress("saving library");
    }
 
-   if (!no_save && !aot_codegen) {
+   if (use_jit && !no_save) {
       FILE *f = lib_fopen(work, pack_name, "wb");
       if (f == NULL)
          fatal_errno("fopen: %s", pack_name);
@@ -503,7 +507,7 @@ static int elaborate(int argc, char **argv, cmd_state_t *state)
       progress("writing JIT pack");
    }
 
-   if (aot_codegen) {
+   if (!use_jit) {
       LLVM_ONLY(cgen(top, state->registry, state->jit));
 
       // Must discard current JIT state to load AOT library later
-- 
2.39.2