Re: [PATCH] Enable using llvm jitlink as an alternative llvm jit linker of old Rtdyld. - Mailing list pgsql-hackers
| From | Alex Fan |
|---|---|
| Subject | Re: [PATCH] Enable using llvm jitlink as an alternative llvm jit linker of old Rtdyld. |
| Date | |
| Msg-id | CAP8f6fAbsQ61WhaTuWctKBaa3y79iBQeaNnKN_Qx=YM4fWNDKg@mail.gmail.com Whole thread Raw |
| In response to | [PATCH] Enable using llvm jitlink as an alternative llvm jit linker of old Rtdyld. (Alex Fan <alex.fan.q@gmail.com>) |
| Responses |
Re: [PATCH] Enable using llvm jitlink as an alternative llvm jit linker of old Rtdyld.
Re: [PATCH] Enable using llvm jitlink as an alternative llvm jit linker of old Rtdyld. |
| List | pgsql-hackers |
Hi,
I am new to the postgres community and apologise for resending this as the previous one didn't include patch properly and didn't cc reviewers (maybe the reason it has been buried in mailing list for months)
Adding to previous email, this patch exposes its own C API for creating ObjectLinkingLayer in a similar fashion as LLVMOrcCreateRTDyldObjectLinkingLayerWithSectionMemoryManager since orc doesn't expose it yet.
Thanks and really appreciate if someone can offer a review to this and help get it merged.
Cheers,
Alex
On Mon, Aug 29, 2022 at 5:46 PM Alex Fan <alex.fan.q@gmail.com> wrote:
This brings the bonus of support jitting on riscv64 (included in this patch)
and other platforms Rtdyld doesn't support, e.g. windows COFF.
Currently, llvm doesn't expose jitlink (ObjectLinkingLayer) via C API, so
a wrapper is added. This also adds minor llvm 15 compat fix that is needed
---
config/llvm.m4 | 1 +
src/backend/jit/llvm/llvmjit.c | 67 +++++++++++++++++++++++++--
src/backend/jit/llvm/llvmjit_wrap.cpp | 35 ++++++++++++++
src/include/jit/llvmjit.h | 9 ++++
4 files changed, 108 insertions(+), 4 deletions(-)
diff --git a/config/llvm.m4 b/config/llvm.m4
index 3a75cd8b4d..a31b8b304a 100644
--- a/config/llvm.m4
+++ b/config/llvm.m4
@@ -75,6 +75,7 @@ AC_DEFUN([PGAC_LLVM_SUPPORT],
engine) pgac_components="$pgac_components $pgac_component";;
debuginfodwarf) pgac_components="$pgac_components $pgac_component";;
orcjit) pgac_components="$pgac_components $pgac_component";;
+ jitlink) pgac_components="$pgac_components $pgac_component";;
passes) pgac_components="$pgac_components $pgac_component";;
native) pgac_components="$pgac_components $pgac_component";;
perfjitevents) pgac_components="$pgac_components $pgac_component";;
diff --git a/src/backend/jit/llvm/llvmjit.c b/src/backend/jit/llvm/llvmjit.c
index 6c72d43beb..d8b840da8c 100644
--- a/src/backend/jit/llvm/llvmjit.c
+++ b/src/backend/jit/llvm/llvmjit.c
@@ -229,6 +229,11 @@ llvm_release_context(JitContext *context)
LLVMModuleRef
llvm_mutable_module(LLVMJitContext *context)
{
+#ifdef __riscv
+ const char* abiname;
+ const char* target_abi = "target-abi";
+ LLVMMetadataRef abi_metadata;
+#endif
llvm_assert_in_fatal_section();
/*
@@ -241,6 +246,40 @@ llvm_mutable_module(LLVMJitContext *context)
context->module = LLVMModuleCreateWithName("pg");
LLVMSetTarget(context->module, llvm_triple);
LLVMSetDataLayout(context->module, llvm_layout);
+#ifdef __riscv
+#if __riscv_xlen == 64
+#ifdef __riscv_float_abi_double
+ abiname = "lp64d";
+#elif defined(__riscv_float_abi_single)
+ abiname = "lp64f";
+#else
+ abiname = "lp64";
+#endif
+#elif __riscv_xlen == 32
+#ifdef __riscv_float_abi_double
+ abiname = "ilp32d";
+#elif defined(__riscv_float_abi_single)
+ abiname = "ilp32f";
+#else
+ abiname = "ilp32";
+#endif
+#else
+ elog(ERROR, "unsupported riscv xlen %d", __riscv_xlen);
+#endif
+ /*
+ * set this manually to avoid llvm defaulting to soft float and
+ * resulting in linker error: `can't link double-float modules
+ * with soft-float modules`
+ * we could set this for TargetMachine via MCOptions, but there
+ * is no C API for it
+ * ref: https://github.com/llvm/llvm-project/blob/afa520ab34803c82587ea6759bfd352579f741b4/llvm/lib/Target/RISCV/RISCVTargetMachine.cpp#L90
+ */
+ abi_metadata = LLVMMDStringInContext2(
+ LLVMGetModuleContext(context->module),
+ abiname, strlen(abiname));
+ LLVMAddModuleFlag(context->module, LLVMModuleFlagBehaviorOverride,
+ target_abi, strlen(target_abi), abi_metadata);
+#endif
}
return context->module;
@@ -786,6 +825,8 @@ llvm_session_initialize(void)
char *error = NULL;
char *cpu = NULL;
char *features = NULL;
+ LLVMRelocMode reloc=LLVMRelocDefault;
+ LLVMCodeModel codemodel=LLVMCodeModelJITDefault;
LLVMTargetMachineRef opt0_tm;
LLVMTargetMachineRef opt3_tm;
@@ -820,16 +861,21 @@ llvm_session_initialize(void)
elog(DEBUG2, "LLVMJIT detected CPU \"%s\", with features \"%s\"",
cpu, features);
+#ifdef __riscv
+ reloc=LLVMRelocPIC;
+ codemodel=LLVMCodeModelMedium;
+#endif
+
opt0_tm =
LLVMCreateTargetMachine(llvm_targetref, llvm_triple, cpu, features,
LLVMCodeGenLevelNone,
- LLVMRelocDefault,
- LLVMCodeModelJITDefault);
+ reloc,
+ codemodel);
opt3_tm =
LLVMCreateTargetMachine(llvm_targetref, llvm_triple, cpu, features,
LLVMCodeGenLevelAggressive,
- LLVMRelocDefault,
- LLVMCodeModelJITDefault);
+ reloc,
+ codemodel);
LLVMDisposeMessage(cpu);
cpu = NULL;
@@ -1112,7 +1158,11 @@ llvm_resolve_symbols(LLVMOrcDefinitionGeneratorRef GeneratorObj, void *Ctx,
LLVMOrcJITDylibRef JD, LLVMOrcJITDylibLookupFlags JDLookupFlags,
LLVMOrcCLookupSet LookupSet, size_t LookupSetSize)
{
+#if LLVM_VERSION_MAJOR > 14
+ LLVMOrcCSymbolMapPairs symbols = palloc0(sizeof(LLVMOrcCSymbolMapPair) * LookupSetSize);
+#else
LLVMOrcCSymbolMapPairs symbols = palloc0(sizeof(LLVMJITCSymbolMapPair) * LookupSetSize);
+#endif
LLVMErrorRef error;
LLVMOrcMaterializationUnitRef mu;
@@ -1160,6 +1210,10 @@ llvm_log_jit_error(void *ctx, LLVMErrorRef error)
static LLVMOrcObjectLayerRef
llvm_create_object_layer(void *Ctx, LLVMOrcExecutionSessionRef ES, const char *Triple)
{
+#if defined(USE_JITLINK)
+ LLVMOrcObjectLayerRef objlayer =
+ LLVMOrcCreateJitlinkObjectLinkingLayer(ES);
+#else
LLVMOrcObjectLayerRef objlayer =
LLVMOrcCreateRTDyldObjectLinkingLayerWithSectionMemoryManager(ES);
@@ -1179,6 +1233,7 @@ llvm_create_object_layer(void *Ctx, LLVMOrcExecutionSessionRef ES, const char *T
LLVMOrcRTDyldObjectLinkingLayerRegisterJITEventListener(objlayer, l);
}
+#endif
#endif
return objlayer;
@@ -1230,7 +1285,11 @@ llvm_create_jit_instance(LLVMTargetMachineRef tm)
* Symbol resolution support for "special" functions, e.g. a call into an
* SQL callable function.
*/
+#if LLVM_VERSION_MAJOR > 14
+ ref_gen = LLVMOrcCreateCustomCAPIDefinitionGenerator(llvm_resolve_symbols, NULL, NULL);
+#else
ref_gen = LLVMOrcCreateCustomCAPIDefinitionGenerator(llvm_resolve_symbols, NULL);
+#endif
LLVMOrcJITDylibAddGenerator(LLVMOrcLLJITGetMainJITDylib(lljit), ref_gen);
return lljit;
diff --git a/src/backend/jit/llvm/llvmjit_wrap.cpp b/src/backend/jit/llvm/llvmjit_wrap.cpp
index 8f11cc02b2..29f21f1715 100644
--- a/src/backend/jit/llvm/llvmjit_wrap.cpp
+++ b/src/backend/jit/llvm/llvmjit_wrap.cpp
@@ -27,6 +27,10 @@ extern "C"
#include <llvm/Support/Host.h>
#include "jit/llvmjit.h"
+#ifdef USE_JITLINK
+#include "llvm/ExecutionEngine/JITLink/EHFrameSupport.h"
+#include "llvm/ExecutionEngine/Orc/ObjectLinkingLayer.h"
+#endif
/*
@@ -48,6 +52,19 @@ char *LLVMGetHostCPUFeatures(void) {
for (auto &F : HostFeatures)
Features.AddFeature(F.first(), F.second);
+#if defined(__riscv)
+ /* getHostCPUName returns "generic-rv[32|64]", which lacks all features */
+ Features.AddFeature("m", true);
+ Features.AddFeature("a", true);
+ Features.AddFeature("c", true);
+# if defined(__riscv_float_abi_single)
+ Features.AddFeature("f", true);
+# endif
+# if defined(__riscv_float_abi_double)
+ Features.AddFeature("d", true);
+# endif
+#endif
+
return strdup(Features.getString().c_str());
}
#endif
@@ -76,3 +93,21 @@ LLVMGetAttributeCountAtIndexPG(LLVMValueRef F, uint32 Idx)
*/
return LLVMGetAttributeCountAtIndex(F, Idx);
}
+
+#ifdef USE_JITLINK
+/*
+ * There is no public C API to create ObjectLinkingLayer for JITLINK, create our own
+ */
+DEFINE_SIMPLE_CONVERSION_FUNCTIONS(llvm::orc::ExecutionSession, LLVMOrcExecutionSessionRef)
+DEFINE_SIMPLE_CONVERSION_FUNCTIONS(llvm::orc::ObjectLayer, LLVMOrcObjectLayerRef)
+
+LLVMOrcObjectLayerRef
+LLVMOrcCreateJitlinkObjectLinkingLayer(LLVMOrcExecutionSessionRef ES)
+{
+ assert(ES && "ES must not be null");
+ auto ObjLinkingLayer = new llvm::orc::ObjectLinkingLayer(*unwrap(ES));
+ ObjLinkingLayer->addPlugin(std::make_unique<llvm::orc::EHFrameRegistrationPlugin>(
+ *unwrap(ES), std::make_unique<llvm::jitlink::InProcessEHFrameRegistrar>()));
+ return wrap(ObjLinkingLayer);
+}
+#endif
diff --git a/src/include/jit/llvmjit.h b/src/include/jit/llvmjit.h
index 4541f9a2c4..85a0cfe5e0 100644
--- a/src/include/jit/llvmjit.h
+++ b/src/include/jit/llvmjit.h
@@ -19,6 +19,11 @@
#include <llvm-c/Types.h>
+#if defined(__riscv) && LLVM_VERSION_MAJOR >= 15
+#include <llvm-c/Orc.h>
+#define USE_JITLINK
+/* else use legacy RTDyld */
+#endif
/*
* File needs to be includable by both C and C++ code, and include other
@@ -134,6 +139,10 @@ extern char *LLVMGetHostCPUFeatures(void);
extern unsigned LLVMGetAttributeCountAtIndexPG(LLVMValueRef F, uint32 Idx);
+#ifdef USE_JITLINK
+extern LLVMOrcObjectLayerRef LLVMOrcCreateJitlinkObjectLinkingLayer(LLVMOrcExecutionSessionRef ES);
+#endif
+
#ifdef __cplusplus
} /* extern "C" */
#endif
--
2.37.2
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