From dca9347c39cfca45de969ee49536962836ccbba4 Mon Sep 17 00:00:00 2001
From: Dmitrii Dolgov <9erthalion6@gmail.com>
Date: Mon, 23 Sep 2024 19:08:52 +0200
Subject: [PATCH v2] Add jit provider's version into the pgsql_version

If jit provider is available and initialized, add its version string
into the pgsql_version output. This should help to get more relevant
information in bug reports about JIT.
---
 src/backend/jit/jit.c           | 13 +++++++++++++
 src/backend/jit/llvm/llvmjit.c  | 17 +++++++++++++++++
 src/backend/utils/adt/version.c | 15 ++++++++++++++-
 src/include/jit/jit.h           |  8 ++++++++
 src/include/jit/llvmjit.h       |  2 ++
 5 files changed, 54 insertions(+), 1 deletion(-)

diff --git a/src/backend/jit/jit.c b/src/backend/jit/jit.c
index 815b58f..b62422c 100644
--- a/src/backend/jit/jit.c
+++ b/src/backend/jit/jit.c
@@ -188,3 +188,16 @@ InstrJitAgg(JitInstrumentation *dst, JitInstrumentation *add)
 	INSTR_TIME_ADD(dst->optimization_counter, add->optimization_counter);
 	INSTR_TIME_ADD(dst->emission_counter, add->emission_counter);
 }
+
+/*
+ * Return JIT provider's version string for troubleshooting purposes.
+ */
+const char *
+jit_get_version(bool *available)
+{
+	if (provider_init())
+		return provider.get_version(available);
+
+	*available = false;
+	return "";
+}
diff --git a/src/backend/jit/llvm/llvmjit.c b/src/backend/jit/llvm/llvmjit.c
index 0f6cec5..3ab1080 100644
--- a/src/backend/jit/llvm/llvmjit.c
+++ b/src/backend/jit/llvm/llvmjit.c
@@ -165,6 +165,7 @@ _PG_jit_provider_init(JitProviderCallbacks *cb)
 	cb->reset_after_error = llvm_reset_after_error;
 	cb->release_context = llvm_release_context;
 	cb->compile_expr = llvm_compile_expr;
+	cb->get_version = llvm_version;
 }
 
 
@@ -1382,3 +1383,19 @@ ResOwnerReleaseJitContext(Datum res)
 	context->resowner = NULL;
 	jit_release_context(&context->base);
 }
+
+const char *
+llvm_version(bool *available)
+{
+#if LLVM_VERSION_MAJOR > 15
+	unsigned int major, minor, patch;
+
+	LLVMGetVersion(&major, &minor, &patch);
+
+	*available = true;
+	return (const char*) psprintf("llvm: %d.%d.%d", major, minor, patch);
+#else
+	*available = false;
+	return "";
+#endif
+}
diff --git a/src/backend/utils/adt/version.c b/src/backend/utils/adt/version.c
index 28db1f6..fabaf73 100644
--- a/src/backend/utils/adt/version.c
+++ b/src/backend/utils/adt/version.c
@@ -15,10 +15,23 @@
 #include "postgres.h"
 
 #include "utils/builtins.h"
+#include "jit/jit.h"
 
 
 Datum
 pgsql_version(PG_FUNCTION_ARGS)
 {
-	PG_RETURN_TEXT_P(cstring_to_text(PG_VERSION_STR));
+	bool jit_available = false;
+	const char *jit_version = jit_get_version(&jit_available);
+
+	/* Add jit provides's version string if available. */
+	if (jit_available)
+	{
+		PG_RETURN_TEXT_P(cstring_to_text(psprintf("%s, %s", PG_VERSION_STR,
+												  jit_version)));
+	}
+	else
+	{
+		PG_RETURN_TEXT_P(cstring_to_text(PG_VERSION_STR));
+	}
 }
diff --git a/src/include/jit/jit.h b/src/include/jit/jit.h
index d9a080c..35d5a62 100644
--- a/src/include/jit/jit.h
+++ b/src/include/jit/jit.h
@@ -70,12 +70,14 @@ typedef void (*JitProviderResetAfterErrorCB) (void);
 typedef void (*JitProviderReleaseContextCB) (JitContext *context);
 struct ExprState;
 typedef bool (*JitProviderCompileExprCB) (struct ExprState *state);
+typedef const char* (*JitProviderVersion) (bool *available);
 
 struct JitProviderCallbacks
 {
 	JitProviderResetAfterErrorCB reset_after_error;
 	JitProviderReleaseContextCB release_context;
 	JitProviderCompileExprCB compile_expr;
+	JitProviderVersion get_version;
 };
 
 
@@ -102,5 +104,11 @@ extern void jit_release_context(JitContext *context);
 extern bool jit_compile_expr(struct ExprState *state);
 extern void InstrJitAgg(JitInstrumentation *dst, JitInstrumentation *add);
 
+/*
+ * Get the provider's version string. The flag indicating availability is
+ * passed as an argument, and will be set accordingly if it's not possible to
+ * get the version.
+ */
+extern const char *jit_get_version(bool *available);
 
 #endif							/* JIT_H */
diff --git a/src/include/jit/llvmjit.h b/src/include/jit/llvmjit.h
index 420775b..898848a 100644
--- a/src/include/jit/llvmjit.h
+++ b/src/include/jit/llvmjit.h
@@ -136,6 +136,8 @@ extern LLVMValueRef slot_compile_deform(struct LLVMJitContext *context, TupleDes
 extern LLVMTypeRef LLVMGetFunctionReturnType(LLVMValueRef r);
 extern LLVMTypeRef LLVMGetFunctionType(LLVMValueRef r);
 
+extern const char* llvm_version(bool *available);
+
 #ifdef __cplusplus
 } /* extern "C" */
 #endif

base-commit: 6aa44060a3c94ee10273bb8a89e98a5bb2fbbacb
-- 
2.45.1