Add the pony_try function to receive Pony errors in C code (#2457)

This function is implemented in LLVM IR since it cannot be implemented
in C.

This change also exposes the `pony_error` function (renamed from
`pony_throw`) in the public runtime interface in order to allow C
programs to both raise and receive Pony errors.

.gitignore

@@ -30,3 +30,6 @@ output/
 _ReSharper.*
 .vscode/
 src/common/dtrace_probes.h
+
+# Allow these paths
+!src/libponyrt/lang/except_try_catch.ll

Makefile

@@ -102,6 +102,7 @@ ALL_CFLAGS = -std=gnu11 -fexceptions \
   -DPONY_VERSION_STR=\"$(version_str)\" \
   -D_FILE_OFFSET_BITS=64
 ALL_CXXFLAGS = -std=gnu++11 -fno-rtti
+LL_FLAGS = -mcpu=$(arch)
 
 # Determine pointer size in bits.
 BITS := $(bits)
@@ -178,6 +179,7 @@ endif
 
 ifeq ($(config),release)
   BUILD_FLAGS += -O3 -DNDEBUG
+  LL_FLAGS += -O3
 
   ifeq ($(lto),yes)
     BUILD_FLAGS += -flto -DPONY_USE_LTO
@@ -201,73 +203,50 @@ ifeq ($(OSTYPE),osx)
 endif
 
 ifndef LLVM_CONFIG
-	ifneq (,$(shell which /usr/local/opt/llvm/bin/llvm-config 2> /dev/null))
+  ifneq (,$(shell which /usr/local/opt/llvm/bin/llvm-config 2> /dev/null))
     LLVM_CONFIG = /usr/local/opt/llvm/bin/llvm-config
-    LLVM_LINK = /usr/local/opt/llvm/bin/llvm-link
-    LLVM_OPT = /usr/local/opt/llvm/bin/opt
   else ifneq (,$(shell which llvm-config-3.9 2> /dev/null))
     LLVM_CONFIG = llvm-config-3.9
-    LLVM_LINK = llvm-link-3.9
-		LLVM_OPT = opt-3.9
   else ifneq (,$(shell which /usr/local/opt/[email protected]/bin/llvm-config 2> /dev/null))
     LLVM_CONFIG = /usr/local/opt/[email protected]/bin/llvm-config
-    LLVM_LINK = /usr/local/opt/[email protected]/bin/llvm-link
-    LLVM_OPT = /usr/local/opt/[email protected]/bin/opt
   else ifneq (,$(shell which llvm-config-3.8 2> /dev/null))
     LLVM_CONFIG = llvm-config-3.8
-    LLVM_LINK = llvm-link-3.8
-    LLVM_OPT = opt-3.8
   else ifneq (,$(shell which llvm-config-mp-3.8 2> /dev/null))
     LLVM_CONFIG = llvm-config-mp-3.8
-    LLVM_LINK = llvm-link-mp-3.8
-    LLVM_OPT = opt-mp-3.8
   else ifneq (,$(shell which llvm-config-3.7 2> /dev/null))
     LLVM_CONFIG = llvm-config-3.7
-    LLVM_LINK = llvm-link-3.7
-    LLVM_OPT = opt-3.7
   else ifneq (,$(shell which llvm-config-3.6 2> /dev/null))
     LLVM_CONFIG = llvm-config-3.6
-    LLVM_LINK = llvm-link-3.6
-    LLVM_OPT = opt-3.6
   else ifneq (,$(shell which llvm-config39 2> /dev/null))
     LLVM_CONFIG = llvm-config39
-    LLVM_LINK = llvm-link39
-    LLVM_OPT = opt39
   else ifneq (,$(shell which llvm-config38 2> /dev/null))
     LLVM_CONFIG = llvm-config38
-    LLVM_LINK = llvm-link38
-    LLVM_OPT = opt38
   else ifneq (,$(shell which llvm-config37 2> /dev/null))
     LLVM_CONFIG = llvm-config37
-    LLVM_LINK = llvm-link37
-    LLVM_OPT = opt37
   else ifneq (,$(shell which /usr/local/opt/llvm/bin/llvm-config 2> /dev/null))
     LLVM_CONFIG = /usr/local/opt/llvm/bin/llvm-config
-    LLVM_LINK = /usr/local/opt/llvm/bin/llvm-link
-    LLVM_OPT = /usr/local/opt/llvm/bin/opt
   else ifneq (,$(shell which llvm-config 2> /dev/null))
     LLVM_CONFIG = llvm-config
-    LLVM_LINK = llvm-link
-    LLVM_OPT = opt
   else ifneq (,$(shell which llvm-config-5.0 2> /dev/null))
     LLVM_CONFIG = llvm-config-5.0
-    LLVM_LINK = llvm-link-5.0
-    LLVM_OPT = opt-5.0
   else ifneq (,$(shell which llvm-config-4.0 2> /dev/null))
     LLVM_CONFIG = llvm-config-4.0
-    LLVM_LINK = llvm-link-4.0
-    LLVM_OPT = opt-4.0
-	else ifneq (,$(shell which /usr/local/opt/[email protected]/bin/llvm-config 2> /dev/null))
+  else ifneq (,$(shell which /usr/local/opt/[email protected]/bin/llvm-config 2> /dev/null))
     LLVM_CONFIG = /usr/local/opt/[email protected]/bin/llvm-config
-    LLVM_LINK = /usr/local/opt/[email protected]/bin/llvm-link
-    LLVM_OPT = /usr/local/opt/[email protected]/bin/opt
+  else
+    $(error No LLVM installation found!)
   endif
-endif
-
-ifndef LLVM_CONFIG
+else ifeq (,$(shell which $(LLVM_CONFIG) 2> /dev/null))
   $(error No LLVM installation found!)
 endif
 
+LLVM_BINDIR := $(shell $(LLVM_CONFIG) --bindir 2> /dev/null)
+
+LLVM_LINK := $(LLVM_BINDIR)/llvm-link
+LLVM_OPT := $(LLVM_BINDIR)/opt
+LLVM_LLC := $(LLVM_BINDIR)/llc
+LLVM_AS := $(LLVM_BINDIR)/llvm-as
+
 llvm_version := $(shell $(LLVM_CONFIG) --version)
 
 ifeq (,$(LLVM_LINK_STATIC))
@@ -278,9 +257,8 @@ ifeq (,$(LLVM_LINK_STATIC))
 endif
 
 ifeq ($(OSTYPE),osx)
-	llvm_bindir := $(shell $(LLVM_CONFIG) --bindir $(LLVM_LINK_STATIC))
-  ifneq (,$(shell which $(llvm_bindir)/llvm-ar 2> /dev/null))
-    AR = $(llvm_bindir)/llvm-ar
+  ifneq (,$(shell which $(LLVM_BINDIR)/llvm-ar 2> /dev/null))
+    AR = $(LLVM_BINDIR)/llvm-ar
     AR_FLAGS := rcs
   else ifneq (,$(shell which llvm-ar-mp-3.8 2> /dev/null))
     AR = llvm-ar-mp-3.8
@@ -290,7 +268,7 @@ ifeq ($(OSTYPE),osx)
     AR_FLAGS := rcs
   else
     AR = /usr/bin/ar
-		AR_FLAGS := -rcs
+    AR_FLAGS := -rcs
   endif
 endif
 
@@ -510,11 +488,13 @@ endif
 
 ifeq ($(OSTYPE), linux)
   libponyrt-pic.buildoptions += -fpic
+  libponyrt-pic.buildoptions-ll += -relocation-model=pic
 endif
 
 # default enable PIC compiling if requested
 ifdef default_pic
   libponyrt.buildoptions += -fpic
+  libponyrt.buildoptions-ll += -relocation-model=pic
   BUILD_FLAGS += -DPONY_DEFAULT_PIC=true
 endif
 
@@ -613,7 +593,7 @@ define ENUMERATE
     sourcefiles := $$($(1).files)
   else
     sourcefiles := $$(shell find $$(sourcedir) -type f -name "*.c" -or -name\
-      "*.cc" | grep -v '.*/\.')
+      "*.cc" -or -name "*.ll" | grep -v '.*/\.')
   endif
 
   ifdef $(1).except
@@ -631,11 +611,16 @@ define CONFIGURE_COMPILER
     compiler := $(CC)
     flags := $(ALL_CFLAGS) $(CFLAGS)
   endif
-
+  
   ifeq ($(suffix $(1)),.bc)
     compiler := $(CC)
     flags := $(ALL_CFLAGS) $(CFLAGS)
   endif
+
+  ifeq ($(suffix $(1)),.ll)
+    compiler := $(CC)
+    flags := $(ALL_CFLAGS) $(CFLAGS) -Wno-override-module
+  endif
 endef
 
 define CONFIGURE_LIBS
@@ -691,8 +676,8 @@ define PREPARE
   $(eval objectfiles  := $(subst $(sourcedir)/,$(outdir)/,$(addsuffix .o,\
     $(sourcefiles))))
   $(eval bitcodefiles := $(subst .o,.bc,$(objectfiles)))
-  $(eval dependencies := $(subst .c,,$(subst .cc,,$(subst .o,.d,\
-    $(objectfiles)))))
+  $(eval dependencies := $(subst .c,,$(subst .cc,,$(subst .ll,,$(subst .o,.d,\
+    $(objectfiles))))))
 endef
 
 define EXPAND_OBJCMD
@@ -701,17 +686,27 @@ $(eval $(call CONFIGURE_COMPILER,$(file)))
 
 ifeq ($(3),libponyrtyes)
   ifneq ($(suffix $(file)),.bc)
-$(subst .c,,$(subst .cc,,$(1))): $(subst .c,.bc,$(subst .cc,.bc,$(file)))
+$(subst .c,,$(subst .cc,,$(subst .ll,,$(1)))): $(subst .c,.bc,$(subst .cc,.bc,$(subst .ll,.bc,$(file))))
 	@echo '$$(notdir $$<)'
 	@mkdir -p $$(dir $$@)
 	$(SILENT)$(compiler) $(flags) -c -o $$@ $$<
+  else ifeq ($(suffix $(subst .bc,,$(file))),.ll)
+$(subst .ll,,$(1)): $(subst $(outdir)/,$(sourcedir)/,$(subst .bc,,$(file)))
+	@echo '$$(notdir $$<)'
+	@mkdir -p $$(dir $$@)
+	$(SILENT)$(LLVM_AS) -o $$@ $$<
   else
 $(subst .c,,$(subst .cc,,$(1))): $(subst $(outdir)/,$(sourcedir)/,$(subst .bc,,$(file)))
 	@echo '$$(notdir $$<)'
 	@mkdir -p $$(dir $$@)
 	$(SILENT)$(compiler) -MMD -MP $(filter-out $($(2).disable),$(BUILD_FLAGS)) \
     $(flags) $($(2).buildoptions) -emit-llvm -c -o $$@ $$<  $($(2).include)
   endif
+else ifeq ($(suffix $(file)),.ll)
+$(subst .ll,,$(1)): $(subst $(outdir)/,$(sourcedir)/,$(file))
+	@echo '$$(notdir $$<)'
+	@mkdir -p $$(dir $$@)
+	$(SILENT)$(LLVM_LLC) $(LL_FLAGS) $($(2).buildoptions-ll) -filetype=obj -o $$@ $$<
 else
 $(subst .c,,$(subst .cc,,$(1))): $(subst $(outdir)/,$(sourcedir)/,$(file))
 	@echo '$$(notdir $$<)'
@@ -723,8 +718,8 @@ endef
 
 define EXPAND_COMMAND
 $(eval $(call PREPARE,$(1)))
-$(eval ofiles := $(subst .c,,$(subst .cc,,$(objectfiles))))
-$(eval bcfiles := $(subst .c,,$(subst .cc,,$(bitcodefiles))))
+$(eval ofiles := $(subst .c,,$(subst .cc,,$(subst .ll,,$(objectfiles)))))
+$(eval bcfiles := $(subst .c,,$(subst .cc,,$(subst .ll,,$(bitcodefiles)))))
 $(eval depends := )
 $(foreach d,$($(1).depends),$(eval depends += $($(d))/$(d).$(LIB_EXT)))
 

src/libponyc/codegen/codegen.c

@@ -787,9 +787,9 @@ static void init_runtime(compile_t* c)
   LLVMAddFunctionAttr(value, LLVMReadOnlyAttribute);
 #endif
 
-  // void pony_throw()
+  // void pony_error()
   type = LLVMFunctionType(c->void_type, NULL, 0, false);
-  value = LLVMAddFunction(c->module, "pony_throw", type);
+  value = LLVMAddFunction(c->module, "pony_error", type);
 #if PONY_LLVM >= 309
   LLVMAddAttributeAtIndex(value, LLVMAttributeFunctionIndex, noreturn_attr);
 #else

src/libponyc/codegen/gencall.c

@@ -1359,9 +1359,9 @@ LLVMValueRef gencall_allocstruct(compile_t* c, reach_type_t* t)
   return result;
 }
 
-void gencall_throw(compile_t* c)
+void gencall_error(compile_t* c)
 {
-  LLVMValueRef func = LLVMGetNamedFunction(c->module, "pony_throw");
+  LLVMValueRef func = LLVMGetNamedFunction(c->module, "pony_error");
 
   if(c->frame->invoke_target != NULL)
     invoke_fun(c, func, NULL, 0, "", false);

src/libponyc/codegen/gencall.h

@@ -27,7 +27,7 @@ LLVMValueRef gencall_alloc(compile_t* c, reach_type_t* t);
 
 LLVMValueRef gencall_allocstruct(compile_t* c, reach_type_t* t);
 
-void gencall_throw(compile_t* c);
+void gencall_error(compile_t* c);
 
 void gencall_memcpy(compile_t* c, LLVMValueRef dst, LLVMValueRef src,
   LLVMValueRef n);

src/libponyc/codegen/gencontrol.c

@@ -629,7 +629,7 @@ LLVMValueRef gen_error(compile_t* c, ast_t* ast)
 
   codegen_scope_lifetime_end(c);
   codegen_debugloc(c, ast);
-  gencall_throw(c);
+  gencall_error(c);
   codegen_debugloc(c, NULL);
 
   return GEN_NOVALUE;

src/libponyc/codegen/genprim.c

@@ -581,7 +581,7 @@ static void maybe_apply(compile_t* c, void* data, token_id cap)
   LLVMBuildRet(c->builder, result);
 
   LLVMPositionBuilderAtEnd(c->builder, is_true);
-  gencall_throw(c);
+  gencall_error(c);
 
   codegen_finishfun(c);
 }

src/libponyrt/gc/serialise.c

@@ -4,7 +4,6 @@
 
 #include "serialise.h"
 #include "../sched/scheduler.h"
-#include "../lang/lang.h"
 #include "ponyassert.h"
 #include <string.h>
 

src/libponyrt/lang/directory.c

@@ -2,7 +2,6 @@
 
 #include <platform.h>
 #include <pony.h>
-#include "lang.h"
 #include <string.h>
 
 #if defined(PLATFORM_IS_WINDOWS)

src/libponyrt/lang/except_try_catch.ll

@@ -0,0 +1,22 @@
+; This file implements the `pony_try` function in LLVM IR as it cannot be
+; implemented in C.
+; Since the LLVM project doesn't particularly care about IR backwards
+; compatibility, please try to keep this file as minimal as possible in order
+; to minimise the chances of breakage with newer LLVM versions.
+
+declare i32 @pony_personality_v0(...)
+
+define i1 @pony_try(void (i8*)* %fun, i8* %ctx) personality i32 (...)* @pony_personality_v0 {
+entry:
+  invoke void %fun(i8* %ctx)
+    to label %post unwind label %unwind
+
+unwind:
+  %lp = landingpad { i8*, i32 }
+    catch i8* null
+  br label %post
+
+post:
+  %ret = phi i1 [ true, %entry ], [ false, %unwind ]
+  ret i1 %ret
+}

src/libponyrt/lang/paths.c

@@ -1,6 +1,5 @@
 #include <platform.h>
 #include <pony.h>
-#include "lang.h"
 #include <string.h>
 
 PONY_EXTERN_C_BEGIN

src/libponyrt/lang/posix_except.c

@@ -24,7 +24,7 @@ static void exception_cleanup(_Unwind_Reason_Code reason,
   (void)exception;
 }
 
-PONY_API void pony_throw()
+PONY_API void pony_error()
 {
 #ifdef PLATFORM_IS_ARM
   memcpy(exception.exception_class, "Pony\0\0\0\0", 8);