Silence all warnings when building with GCC on Linux (#44350)

* Silence all warnings when building with GCC on Linux

* Replace `#warning` with `#pragma message`

The former causes a compiler warning with Clang about it being a language
extension, which then causes an error if building with `-Werror`.

* Silence warning about unused variable when doing a non-debug build

* Initialise another variable which can be detected as uninitialised

* Fix more warnings introduced by recent changes

src/ccall.cpp

@@ -347,7 +347,7 @@ static bool is_native_simd_type(jl_datatype_t *dt) {
 #elif defined _CPU_PPC64_
   typedef ABI_PPC64leLayout DefaultAbiState;
 #else
-#  warning "ccall is defaulting to llvm ABI, since no platform ABI has been defined for this CPU/OS combination"
+#  pragma message("ccall is defaulting to llvm ABI, since no platform ABI has been defined for this CPU/OS combination")
   typedef ABI_LLVMLayout DefaultAbiState;
 #endif
 

src/cgutils.cpp

@@ -3348,7 +3348,7 @@ static jl_cgval_t emit_setfield(jl_codectx_t &ctx,
         Value *ptindex = ctx.builder.CreateInBoundsGEP(getInt8Ty(ctx.builder.getContext()), emit_bitcast(ctx, maybe_decay_tracked(ctx, addr), getInt8PtrTy(ctx.builder.getContext())), ConstantInt::get(getSizeTy(ctx.builder.getContext()), fsz));
         if (needlock)
             emit_lockstate_value(ctx, strct, true);
-        BasicBlock *ModifyBB;
+        BasicBlock *ModifyBB = NULL;
         if (ismodifyfield) {
             ModifyBB = BasicBlock::Create(ctx.builder.getContext(), "modify_xchg", ctx.f);
             ctx.builder.CreateBr(ModifyBB);

src/crc32c.c

@@ -346,7 +346,7 @@ static crc32c_func_t crc32c_dispatch(unsigned long hwcap)
 #    define crc32c_dispatch() crc32c_dispatch(getauxval(AT_HWCAP))
 #    define crc32c_dispatch_ifunc "crc32c_dispatch"
 #  else
-#  warning CRC32 feature detection not implemented for this OS. Falling back to software version.
+#  pragma message("CRC32 feature detection not implemented for this OS. Falling back to software version.")
 #  endif
 #else
 // If we don't have any accelerated version to define, just make the _sw version define

src/dlload.c

@@ -159,6 +159,7 @@ JL_DLLEXPORT void *jl_load_dynamic_library(const char *modname, unsigned flags,
     // number of extensions to try — if modname already ends with the
     // standard extension, then we don't try adding additional extensions
     int n_extensions = endswith_extension(modname) ? 1 : N_EXTENSIONS;
+    int ret;
 
     /*
       this branch returns handle of libjulia-internal
@@ -228,8 +229,12 @@ JL_DLLEXPORT void *jl_load_dynamic_library(const char *modname, unsigned flags,
                     path[0] = '\0';
                     if (relocated[len-1] == PATHSEPSTRING[0])
                         snprintf(path, PATHBUF, "%s%s%s", relocated, modname, ext);
-                    else
-                        snprintf(path, PATHBUF, "%s" PATHSEPSTRING "%s%s", relocated, modname, ext);
+                    else {
+                        ret = snprintf(path, PATHBUF, "%s" PATHSEPSTRING "%s%s", relocated, modname, ext);
+                        if (ret < 0)
+                            jl_errorf("path is longer than %d\n", PATHBUF);
+                    }
+
 #ifdef _OS_WINDOWS_
                     if (i == 0) { // LoadLibrary already tested the extensions, we just need to check the `stat` result
 #endif
@@ -299,7 +304,7 @@ JL_DLLEXPORT int jl_dlsym(void *handle, const char *symbol, void ** value, int t
      */
     symbol_found = *value != NULL;
 #ifndef _OS_WINDOWS_
-    const char *err;
+    const char *err = "";
     if (!symbol_found) {
         dlerror(); /* Reset error status. */
         *value = dlsym(handle, symbol);

src/dump.c

@@ -1071,6 +1071,7 @@ static void serialize_htable_keys(jl_serializer_state *s, htable_t *ht, int nite
     write_int32(s->s, nitems);
     void **table = ht->table;
     size_t i, n = 0, sz = ht->size;
+    (void)n;
     for (i = 0; i < sz; i += 2) {
         if (table[i+1] != HT_NOTFOUND) {
             jl_serialize_value(s, (jl_value_t*)table[i]);

src/gc-debug.c

@@ -983,13 +983,13 @@ void gc_time_summary(int sweep_full, uint64_t start, uint64_t end,
                      uint64_t pause)
 {
     if (sweep_full > 0)
-        jl_safe_printf("%ld Major collection: estimate freed = %ld
-                       live = %ldm new interval = %ldm time = %ldms\n",
+        jl_safe_printf("%ld Major collection: estimate freed = %ld\n"
+                       "live = %ldm new interval = %ldm time = %ldms\n",
                        end - start, freed, live/1024/1024,
                        interval/1024/1024, pause/1000000 );
     else
-        jl_safe_printf("%ld Minor collection: estimate freed = %ld live = %ldm
-                       new interval = %ldm time = %ldms\n",
+        jl_safe_printf("%ld Minor collection: estimate freed = %ld live = %ldm\n"
+                       "new interval = %ldm time = %ldms\n",
                        end - start, freed, live/1024/1024,
                        interval/1024/1024, pause/1000000 );
 }

src/jitlayers.cpp

@@ -1120,7 +1120,7 @@ StringRef JuliaOJIT::getFunctionAtAddress(uint64_t Addr, jl_code_instance_t *cod
 
 #ifdef JL_USE_JITLINK
 # if JL_LLVM_VERSION < 140000
-#  warning "JIT debugging (GDB integration) not available on LLVM < 14.0 (for JITLink)"
+#  pragma message("JIT debugging (GDB integration) not available on LLVM < 14.0 (for JITLink)")
 void JuliaOJIT::enableJITDebuggingSupport() {}
 # else
 extern "C" orc::shared::CWrapperFunctionResult

src/jitlayers.h

@@ -32,7 +32,7 @@
 // for Mac/aarch64.
 #if defined(_OS_DARWIN_) && defined(_CPU_AARCH64_)
 # if JL_LLVM_VERSION < 130000
-#  warning "On aarch64-darwin, LLVM version >= 13 is required for JITLink; fallback suffers from occasional segfaults"
+#  pragma message("On aarch64-darwin, LLVM version >= 13 is required for JITLink; fallback suffers from occasional segfaults")
 # endif
 # define JL_USE_JITLINK
 #endif