turbo-ext: shared code compiles identically against PHP 8.3-8.6 (clang)

The last differences between the header sets, each pinned in abi.h or moved into Abi.cpp: - the fresh-C-stack switch (a zend_fiber_context, its switch and a zend_try, whose SETJMP became sigsetjmp in 8.6) is implemented per minor - codegen pins for helpers 8.6 re-spelled without changing what they do: zend_string_equals_literal_ci / _equals_ci / starts_with_literal(_ci), ZSTR_IS_INTERNED, array_init(_size), Z_TRY_ADDREF_P / Z_TRY_DELREF_P - the comparison treats the zend_result rename (a different mangling of the same enum) and the symbol/section name tables as names, not code clang 14 in the CI images (gate-linux.sh with GATE_IMAGE=turbo-build-clang, -fgnuc-version=4.3 so the older headers enable ZEND_COLD for it too) now finds no differing function, data section or relocation outside Abi.o, Shadow.o, TrustedTypes.o and main.o across 8.3, 8.4, 8.5 and 8.6. GCC still differs in 15 string-building functions (8.6 const-qualified zval_get_string() and friends, inline helpers compiled inside the headers). Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_017h1GfB7vfJPgwcTHD9Fth6
ondrejmirtes · Oct 8, 2026 · Oct 8, 2026 · Oct 8, 2026 · Oct 8, 2026 · Oct 8, 2026
commit 2ccc4c9ca9dc1ebd27e8cf5576f0c285a4a6fb26
diff --git a/turbo-ext/bin/shared-core/compare-data-linux.sh b/turbo-ext/bin/shared-core/compare-data-linux.sh
@@ -4,8 +4,8 @@
 S=${SHARED_CORE_WORK_DIR:?set SHARED_CORE_WORK_DIR to a scratch directory}
 O=${LLVM_OBJDUMP:-/opt/homebrew/opt/llvm/bin/llvm-objdump}
 A=$1; B=$2
-norm_relocs() { $O -r "$1" | grep -v 'file format' | sed -E 's/\.L[A-Za-z]*[0-9]+/.L/g'; }
-data() { $O -s "$1" | awk '/^Contents of section / { keep = ($4 !~ /^\.text/ && $4 !~ /^\.comment/) } keep'; }
+norm_relocs() { $O -r "$1" | grep -v 'file format' | sed -E 's/\.L[A-Za-z]*[0-9]+/.L/g; s/16ZEND_RESULT_CODE/11zend_result/g'; }
+data() { $O -s "$1" | sed 's/16ZEND_RESULT_CODE/11zend_result/g' | awk '/^Contents of section / { keep = ($4 !~ /^\.(text|comment|strtab|shstrtab|symtab)/) } keep'; }
 cd "$S/$A"
 for o in $(find src -name '*.o' | sort); do
 	[ "$(data $o | md5)" != "$(data $S/$B/$o | md5)" ] && echo "DATA DIFF $o"

diff --git a/turbo-ext/bin/shared-core/compare-functions.py b/turbo-ext/bin/shared-core/compare-functions.py
@@ -24,7 +24,7 @@ def flush():
 		m = func_re.match(line)
 		if m:
 			flush()
-			cur, lines, n = m.group(1), [], 0
+			cur, lines, n = m.group(1).replace('16ZEND_RESULT_CODE', '11zend_result'), [], 0
 			continue
 		if cur is None:
 			continue
@@ -39,8 +39,14 @@ def flush():
 		s = re.sub(r'\$_\d+', '$_', s)
 		s = re.sub(r'\.cold\.\d+', '.cold', s)
 		s = re.sub(r'(l_\.str|ltmp|LJTI|lJTI|l___const|lCPI)[\.\d_]+', r'\1', s)
-		# GCC's local labels (.LC0, .LANCHOR1, .L42) and clone suffixes
-		s = re.sub(r'\.L[A-Za-z]*\d+', '.L', s)
+		# 8.6 renamed enum ZEND_RESULT_CODE to zend_result: a different
+		# mangling of the same type in our own functions' names
+		s = s.replace('16ZEND_RESULT_CODE', '11zend_result')
+		# local labels: GCC's .LC0, .LANCHOR1, .L42 and clang's .L.str.356 —
+		# numbered in the order the translation unit declares them, so one
+		# more string literal in a header renumbers every later one (their
+		# contents are compared by compare-data-*.sh)
+		s = re.sub(r'(\.L[A-Za-z_.]*?)\.?\d+', r'\1', s)
 		# GCC addresses merged strings through the section of whichever
 		# function emitted them first: section order, not content
 		s = re.sub(r'\.rodata\.[^ +]*\.str1\.\d+(\+0x[0-9a-f]+)?', '.rodata.str', s)

diff --git a/turbo-ext/src/Abi.cpp b/turbo-ext/src/Abi.cpp
@@ -7,7 +7,9 @@
 #include "support.h"
 #include "reg.h"
 
+#include "Engine.h"
 #include "zend_closures.h"
+#include "zend_fibers.h"
 #include "zend_weakrefs.h"
 
 
@@ -237,6 +239,91 @@ static ssize_t abi_stream_read(php_stream *stream, char *buf, size_t count)
 	return php_stream_read(stream, buf, count);
 }
 
+/* {{{ continuing a call on a fresh C stack (pt_engine_with_stack()) */
+
+namespace {
+
+/* one call continued on a fresh stack: the body, and the VM state it left
+ * behind — zend_fiber_switch_context() restores the caller's state from
+ * before the switch, which the body may legitimately have changed */
+struct FreshStackCall
+{
+	void (*body)(void *);
+	void *data;
+	bool bailout;
+	zend_vm_stack vmStack;
+	zval *vmStackTop;
+	zval *vmStackEnd;
+	size_t vmStackPageSize;
+	int errorReporting;
+};
+
+/* the call the coroutine starting next runs (read once, at its start) */
+FreshStackCall *pt_fresh_stack_call = nullptr;
+
+/* identifies the contexts in fiber observers */
+char pt_fresh_stack_kind;
+
+ZEND_STACK_ALIGNED void freshStackCoroutine(zend_fiber_transfer *transfer)
+{
+	(void) transfer; /* already addresses the caller, which is where it returns */
+	FreshStackCall *call = pt_fresh_stack_call;
+	zend_fiber_context *context = EG(current_fiber_context);
+#ifdef ZEND_CHECK_STACK_LIMIT
+	EG(stack_base) = zend_fiber_stack_base(context->stack);
+	EG(stack_limit) = zend_fiber_stack_limit(context->stack);
+#endif
+	zend_try {
+		call->body(call->data);
+	} zend_catch {
+		call->bailout = true;
+	} zend_end_try();
+	call->vmStack = EG(vm_stack);
+	call->vmStackTop = EG(vm_stack_top);
+	call->vmStackEnd = EG(vm_stack_end);
+	call->vmStackPageSize = EG(vm_stack_page_size);
+	call->errorReporting = EG(error_reporting);
+}
+
+} // namespace
+
+static void abi_run_on_fresh_stack(void (*body)(void *), void *data)
+{
+	zend_fiber_context context;
+	memset(&context, 0, sizeof(context));
+	if (UNEXPECTED(zend_fiber_init_context(&context, &pt_fresh_stack_kind, freshStackCoroutine, PT_ENGINE_FRESH_STACK_SIZE_LIMIT) == FAILURE)) {
+		/* no stack to be had: continue here, where the engine's own stack
+		 * limit decides */
+		if (EG(exception) != NULL) {
+			zend_clear_exception();
+		}
+		body(data);
+		return;
+	}
+
+	FreshStackCall call = { body, data, false, NULL, NULL, NULL, 0, 0 };
+	FreshStackCall *previous = pt_fresh_stack_call;
+	pt_fresh_stack_call = &call;
+	zend_fiber_transfer transfer;
+	transfer.context = &context;
+	transfer.flags = 0;
+	ZVAL_NULL(&transfer.value);
+	/* returns once the body finished; the dead context is destroyed then */
+	zend_fiber_switch_context(&transfer);
+	pt_fresh_stack_call = previous;
+
+	EG(vm_stack) = call.vmStack;
+	EG(vm_stack_top) = call.vmStackTop;
+	EG(vm_stack_end) = call.vmStackEnd;
+	EG(vm_stack_page_size) = call.vmStackPageSize;
+	EG(error_reporting) = call.errorReporting;
+	if (UNEXPECTED(call.bailout)) {
+		zend_bailout();
+	}
+}
+
+/* }}} */
+
 void pt_abi_init()
 {
 #define PT_ABI_EG_FIELD(field) pt_abi.eg_##field = &EG(field);
@@ -284,4 +371,5 @@ void pt_abi_init()
 	pt_abi.call_known_function = abi_call_known_function;
 	pt_abi.stream_free = abi_stream_free;
 	pt_abi.stream_read = abi_stream_read;
+	pt_abi.run_on_fresh_stack = abi_run_on_fresh_stack;
 }
diff --git a/turbo-ext/src/Engine.cpp b/turbo-ext/src/Engine.cpp
@@ -479,85 +479,11 @@ bool pt_engine_call_node_callback(zval *callback, zval *node, zval *scope)
 	return !pt_type_call_callable(callback, 2, argv).isUndef();
 }
 
-namespace {
-
-/* one call continued on a fresh stack: the body, and the VM state it left
- * behind — zend_fiber_switch_context() restores the caller's state from
- * before the switch, which the body may legitimately have changed */
-struct FreshStackCall
-{
-	void (*body)(void *);
-	void *data;
-	bool bailout;
-	zend_vm_stack vmStack;
-	zval *vmStackTop;
-	zval *vmStackEnd;
-	size_t vmStackPageSize;
-	int errorReporting;
-};
-
-/* the call the coroutine starting next runs (read once, at its start) */
-FreshStackCall *pt_fresh_stack_call = nullptr;
-
-/* identifies the contexts in fiber observers */
-char pt_fresh_stack_kind;
-
-ZEND_STACK_ALIGNED void freshStackCoroutine(zend_fiber_transfer *transfer)
-{
-	(void) transfer; /* already addresses the caller, which is where it returns */
-	FreshStackCall *call = pt_fresh_stack_call;
-	zend_fiber_context *context = EG(current_fiber_context);
-#ifdef ZEND_CHECK_STACK_LIMIT
-	EG(stack_base) = zend_fiber_stack_base(context->stack);
-	EG(stack_limit) = zend_fiber_stack_limit(context->stack);
-#endif
-	zend_try {
-		call->body(call->data);
-	} zend_catch {
-		call->bailout = true;
-	} zend_end_try();
-	call->vmStack = EG(vm_stack);
-	call->vmStackTop = EG(vm_stack_top);
-	call->vmStackEnd = EG(vm_stack_end);
-	call->vmStackPageSize = EG(vm_stack_page_size);
-	call->errorReporting = EG(error_reporting);
-}
-
-} // namespace
-
 void pt_engine_run_on_fresh_stack(void (*body)(void *), void *data)
 {
-	zend_fiber_context context;
-	memset(&context, 0, sizeof(context));
-	if (UNEXPECTED(zend_fiber_init_context(&context, &pt_fresh_stack_kind, freshStackCoroutine, PT_ENGINE_FRESH_STACK_SIZE_LIMIT) == FAILURE)) {
-		/* no stack to be had: continue here, where the engine's own stack
-		 * limit decides */
-		if (EG(exception) != NULL) {
-			zend_clear_exception();
-		}
-		body(data);
-		return;
-	}
-
-	FreshStackCall call = { body, data, false, NULL, NULL, NULL, 0, 0 };
-	FreshStackCall *previous = pt_fresh_stack_call;
-	pt_fresh_stack_call = &call;
-	zend_fiber_transfer transfer;
-	transfer.context = &context;
-	transfer.flags = 0;
-	ZVAL_NULL(&transfer.value);
-	/* returns once the body finished; the dead context is destroyed then */
-	zend_fiber_switch_context(&transfer);
-	pt_fresh_stack_call = previous;
-
-	EG(vm_stack) = call.vmStack;
-	EG(vm_stack_top) = call.vmStackTop;
-	EG(vm_stack_end) = call.vmStackEnd;
-	EG(vm_stack_page_size) = call.vmStackPageSize;
-	EG(error_reporting) = call.errorReporting;
-	if (UNEXPECTED(call.bailout)) {
-		zend_bailout();
-	}
+	/* the fiber context, its switch and the bailout around the body are
+	 * engine internals of each minor (Abi.cpp) */
+	pt_abi.run_on_fresh_stack(body, data);
 }
 
 /* }}} */

diff --git a/turbo-ext/src/MutatingScope.cpp b/turbo-ext/src/MutatingScope.cpp
@@ -2636,7 +2636,14 @@ class MutatingScope
 			PHP_MD5Update(&context, (const unsigned char *) ZSTR_VAL(parts.s), ZSTR_LEN(parts.s));
 		}
 		PHP_MD5Final(digest, &context);
-		make_digest_ex(hex, digest, sizeof(digest));
+		/* make_digest_ex()'s lowercase hex, spelled out: its length parameter
+		 * became a size_t in 8.5, so a call compiles differently per version */
+		static const char hexDigits[] = "0123456789abcdef";
+		for (size_t i = 0; i < sizeof(digest); i++) {
+			hex[2 * i] = hexDigits[digest[i] >> 4];
+			hex[2 * i + 1] = hexDigits[digest[i] & 0x0f];
+		}
+		hex[32] = '\0';
 		smart_str_free(&parts);
 		return zv::Val::string(hex, 32);
 	}

diff --git a/turbo-ext/src/abi.h b/turbo-ext/src/abi.h
@@ -166,6 +166,9 @@ struct pt_abi_globals
 	void (*call_known_function)(zend_function *fn, zend_object *object, zend_class_entry *calledScope, zval *retval, uint32_t paramCount, zval *params, HashTable *namedParams);
 	int (*stream_free)(php_stream *stream, int closeOptions);
 	ssize_t (*stream_read)(php_stream *stream, char *buf, size_t count);
+	/* pt_engine_run_on_fresh_stack(): a fiber context, its switch and a
+	 * zend_try around the body (8.6 moved SETJMP to sigsetjmp) */
+	void (*run_on_fresh_stack)(void (*body)(void *), void *data);
 };
 
 /* Defined by the shared core, filled by the version-specific library. */
@@ -216,6 +219,53 @@ static zend_always_inline zend_class_entry *pt_abi_class_entry(T *ce)
 #define ZEND_COLD __attribute__((cold))
 #endif
 
+/* Codegen pins: helpers whose result is the same in every minor but whose
+ * spelling changed (8.6 turned macros into inline functions and back), so
+ * the shared code would compile to different instructions per header set.
+ * One definition for all — 8.6's. */
+static zend_always_inline bool pt_abi_string_equals_cstr_ci(const zend_string *s1, const char *s2, size_t s2_length)
+{
+	return ZSTR_LEN(s1) == s2_length && !zend_binary_strcasecmp(ZSTR_VAL(s1), ZSTR_LEN(s1), s2, s2_length);
+}
+static zend_always_inline bool pt_abi_string_is_interned(const zend_string *s)
+{
+	return GC_FLAGS(s) & IS_STR_INTERNED;
+}
+#undef zend_string_equals_literal_ci
+#define zend_string_equals_literal_ci(str, literal) pt_abi_string_equals_cstr_ci(str, "" literal, sizeof(literal) - 1)
+#undef zend_string_starts_with_literal
+#define zend_string_starts_with_literal(str, prefix) zend_string_starts_with_cstr(str, "" prefix, sizeof(prefix) - 1)
+#undef zend_string_starts_with_literal_ci
+#define zend_string_starts_with_literal_ci(str, prefix) zend_string_starts_with_cstr_ci(str, "" prefix, sizeof(prefix) - 1)
+#undef ZSTR_IS_INTERNED
+#define ZSTR_IS_INTERNED(s) pt_abi_string_is_interned(s)
+#undef zend_string_equals_ci
+#define zend_string_equals_ci(s1, s2) pt_abi_string_equals_cstr_ci(s1, ZSTR_VAL(s2), ZSTR_LEN(s2))
+/* array_init(): a macro up to 8.5, an inline function from 8.6 */
+static zend_always_inline void pt_abi_array_init_size(zval *arg, uint32_t size)
+{
+	ZVAL_ARR(arg, zend_new_array(size));
+}
+#undef array_init
+#define array_init(arg) pt_abi_array_init_size((arg), 0)
+#undef array_init_size
+#define array_init_size(arg, size) pt_abi_array_init_size((arg), (size))
+/* 8.5 evaluates the argument once */
+#undef Z_TRY_ADDREF_P
+#define Z_TRY_ADDREF_P(pz) do { \
+		zval *_pz = (pz); \
+		if (Z_REFCOUNTED_P(_pz)) { \
+			Z_ADDREF_P(_pz); \
+		} \
+	} while (0)
+#undef Z_TRY_DELREF_P
+#define Z_TRY_DELREF_P(pz) do { \
+		zval *_pz = (pz); \
+		if (Z_REFCOUNTED_P(_pz)) { \
+			Z_DELREF_P(_pz); \
+		} \
+	} while (0)
+
 #undef EG
 #undef CG
 #define EG(field) (*pt_abi.eg_##field)