111 lines
3.7 KiB
Diff
111 lines
3.7 KiB
Diff
From: Tom Stellard <tstellar@redhat.com>
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From: Jakub Jirutka <jakub@jirutka.cz>
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Date: Sat, 18 Dec 2021 23:09:03 +0100
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Subject: [PATCH] jit: Workaround datalayout mismatch on s390x and x86
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This patch is based on https://src.fedoraproject.org/rpms/postgresql/blob/f35/f/postgresql-datalayout-mismatch-on-s390.patch.
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Original description:
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> LLVM's s390x target uses a different datalayout for z13 and newer processors.
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> If llvmjit_types.bc is compiled to target a processor older than z13, and
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> then the JIT runs on a z13 or newer processor, then there will be a mismatch
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> in datalayouts between llvmjit_types.bc and the JIT engine. This mismatch
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> causes the JIT to fail at runtime.
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We encountered an analogous problem even on x86 (legacy 32bit arch).
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However, I didn't wanna waste my time researching what exact CPU features
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are problematic on this dead architecture, so I just disabled usage of any
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host specific CPU features when creating the JIT on x86. And while I was on
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it, I also conditioned the s390x workaround for s390x only. -jirutka
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diff --git a/src/backend/jit/llvm/llvmjit.c b/src/backend/jit/llvm/llvmjit.c
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index 98a27f08bf..05b6438ba8 100644
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--- a/src/backend/jit/llvm/llvmjit.c
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+++ b/src/backend/jit/llvm/llvmjit.c
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@@ -776,7 +776,38 @@
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errhidecontext(true)));
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}
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+#if defined(__s390__) || defined(__s390x__)
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/*
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+ * For the systemz target, LLVM uses a different datalayout for z13 and newer
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+ * CPUs than it does for older CPUs. This can cause a mismatch in datalayouts
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+ * in the case where the llvm_types_module is compiled with a pre-z13 CPU
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+ * and the JIT is running on z13 or newer.
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+ * See computeDataLayout() function in
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+ * llvm/lib/Target/SystemZ/SystemZTargetMachine.cpp for information on the
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+ * datalayout differences.
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+ */
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+static bool
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+needs_systemz_workaround(void)
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+{
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+ bool ret = false;
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+ LLVMContextRef llvm_context;
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+ LLVMTypeRef vec_type;
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+ LLVMTargetDataRef llvm_layoutref;
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+ if (strncmp(LLVMGetTargetName(llvm_targetref), "systemz", strlen("systemz")))
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+ {
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+ return false;
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+ }
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+
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+ llvm_context = LLVMGetModuleContext(llvm_types_module);
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+ vec_type = LLVMVectorType(LLVMIntTypeInContext(llvm_context, 32), 4);
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+ llvm_layoutref = LLVMCreateTargetData(llvm_layout);
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+ ret = (LLVMABIAlignmentOfType(llvm_layoutref, vec_type) == 16);
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+ LLVMDisposeTargetData(llvm_layoutref);
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+ return ret;
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+}
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+#endif
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+
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+/*
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* Per session initialization.
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*/
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static void
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@@ -785,6 +816,7 @@
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MemoryContext oldcontext;
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char *error = NULL;
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char *cpu = NULL;
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+ char *host_features = NULL;
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char *features = NULL;
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LLVMTargetMachineRef opt0_tm;
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LLVMTargetMachineRef opt3_tm;
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@@ -815,11 +847,22 @@
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* latter is needed because some CPU architectures default to enabling
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* features not all CPUs have (weird, huh).
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*/
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+#if !defined(__i386__) && !defined(__i386) // XXX: quick workaround for 32-bit x86
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cpu = LLVMGetHostCPUName();
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- features = LLVMGetHostCPUFeatures();
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+ features = host_features = LLVMGetHostCPUFeatures();
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elog(DEBUG2, "LLVMJIT detected CPU \"%s\", with features \"%s\"",
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cpu, features);
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+#endif
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+#if defined(__s390__) || defined(__s390x__)
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+ if (needs_systemz_workaround())
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+ {
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+ const char *no_vector =",-vector";
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+ features = malloc(sizeof(char) * (strlen(host_features) + strlen(no_vector) + 1));
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+ sprintf(features, "%s%s", host_features, no_vector);
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+ }
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+#endif
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+
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opt0_tm =
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LLVMCreateTargetMachine(llvm_targetref, llvm_triple, cpu, features,
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LLVMCodeGenLevelNone,
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@@ -833,8 +876,13 @@
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LLVMDisposeMessage(cpu);
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cpu = NULL;
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- LLVMDisposeMessage(features);
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+ if (features != host_features)
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+ {
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+ free(features);
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+ }
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features = NULL;
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+ LLVMDisposeMessage(host_features);
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+ host_features = NULL;
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/* force symbols in main binary to be loaded */
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LLVMLoadLibraryPermanently(NULL);
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