Use ptrdiff_t sized offsets for gvars_offsets to allow large sysimages

Author: gbaraldi

src/aotcompile.cpp

@@ -4,6 +4,8 @@
 #include "platform.h"
 
 // target support
+#include "llvm/IR/Constants.h"
+#include "llvm/Support/Debug.h"
 #include <llvm/TargetParser/Triple.h>
 #include "llvm/Support/CodeGen.h"
 #include <llvm/ADT/Statistic.h>
@@ -199,29 +201,28 @@ static inline SmallVector<T*, 0> consume_gv(Module &M, const char *name, bool al
     return res;
 }
 
-static Constant *get_ptrdiff32(Type *T_size, Constant *ptr, Constant *base)
+static Constant *get_ptrdiff(Type *T_size, Constant *ptr, Constant *base)
 {
     if (ptr->getType()->isPointerTy())
         ptr = ConstantExpr::getPtrToInt(ptr, T_size);
     auto ptrdiff = ConstantExpr::getSub(ptr, base);
-    return T_size->getPrimitiveSizeInBits() > 32 ? ConstantExpr::getTrunc(ptrdiff, Type::getInt32Ty(ptr->getContext())) : ptrdiff;
+    return ptrdiff;
 }
 
 static Constant *emit_offset_table(Module &M, Type *T_size, ArrayRef<Constant*> vars,
                                    StringRef name, StringRef suffix)
 {
-    auto T_int32 = Type::getInt32Ty(M.getContext());
     uint32_t nvars = vars.size();
-    ArrayType *vars_type = ArrayType::get(T_int32, nvars + 1);
+    ArrayType *vars_type = ArrayType::get(T_size, nvars + 1);
     auto gv = new GlobalVariable(M, vars_type, true,
                                  GlobalVariable::ExternalLinkage,
                                  nullptr,
                                  name + "_offsets" + suffix);
     auto vbase = ConstantExpr::getPtrToInt(gv, T_size);
     SmallVector<Constant*, 0> offsets(nvars + 1);
-    offsets[0] = ConstantInt::get(T_int32, nvars);
+    offsets[0] = ConstantInt::get(T_size, nvars);
     for (uint32_t i = 0; i < nvars; i++)
-        offsets[i + 1] = get_ptrdiff32(T_size, vars[i], vbase);
+        offsets[i + 1] = get_ptrdiff(T_size, vars[i], vbase);
     gv->setInitializer(ConstantArray::get(vars_type, offsets));
     gv->setVisibility(GlobalValue::HiddenVisibility);
     gv->setDSOLocal(true);

src/processor.cpp

@@ -772,7 +772,7 @@ static inline jl_image_t parse_sysimg(void *hdl, F &&callback)
     }
 
     if (!gvars.empty()) {
-        auto offsets = (int32_t*)malloc(sizeof(int32_t) * gvars.size());
+        auto offsets = (ptrdiff_t*)malloc(sizeof(ptrdiff_t) * gvars.size());
         res.gvars_base = (const char*)pointers->header;
         for (size_t i = 0; i < gvars.size(); i++) {
             assert(gvars[i] && "Missing global variable pointer!");

src/processor.h

@@ -85,7 +85,7 @@ typedef struct _jl_image_fptrs_t {
 typedef struct {
     uint64_t base;
     const char *gvars_base;
-    const int32_t *gvars_offsets;
+    const ptrdiff_t *gvars_offsets;
     uint32_t ngvars;
     jl_image_fptrs_t fptrs;
     void **jl_small_typeof;
@@ -126,7 +126,7 @@ typedef struct {
     // Similar to fvar_offsets, but for gvars
     // This is also the base data pointer
     // (all data pointers in this shard are stored as offsets to this address)
-    const int32_t *gvar_offsets;
+    const ptrdiff_t *gvar_offsets;
     // This is the mapping of shard global variable index -> global global variable index
     // Similar to fvar_idxs, but for gvars
     const uint32_t *gvar_idxs;

src/staticdata.c

@@ -631,7 +631,7 @@ typedef struct {
 static void *jl_sysimg_handle = NULL;
 static jl_image_t sysimage;
 
-static inline uintptr_t *sysimg_gvars(const char *base, const int32_t *offsets, size_t idx)
+static inline uintptr_t *sysimg_gvars(const char *base, const ptrdiff_t *offsets, size_t idx)
 {
     return (uintptr_t*)(base + offsets[idx]);
 }

test/llvmpasses/multiversioning-clone-only.ll

@@ -3,7 +3,7 @@
 ; RUN: opt --load-pass-plugin=libjulia-codegen%shlibext -passes='JuliaMultiVersioning' -S %s | FileCheck %s --allow-unused-prefixes=false --check-prefixes=CHECK,OPAQUE
 
 ; CHECK: @jl_gvar_base = hidden constant i64 0
-; CHECK: @jl_gvar_offsets = hidden constant [0 x i32] zeroinitializer
+; CHECK: @jl_gvar_offsets = hidden constant [0 x i64] zeroinitializer
 ; CHECK: @jl_fvar_idxs = hidden constant [1 x i32] zeroinitializer
 ; CHECK: @jl_gvar_idxs = hidden constant [0 x i32] zeroinitializer
 ; OPAQUE: @subtarget_cloned_gv = hidden global ptr null
@@ -18,7 +18,7 @@
 
 @jl_fvars = global [1 x i64*] [i64* bitcast (i32 (i32)* @subtarget_cloned to i64*)], align 8
 @jl_gvar_base = hidden constant i64 zeroinitializer, align 8
-@jl_gvar_offsets = hidden constant [0 x i32] zeroinitializer, align 8
+@jl_gvar_offsets = hidden constant [0 x i64] zeroinitializer, align 8
 @jl_fvar_idxs = hidden constant [1 x i32] [i32 0], align 8
 @jl_gvar_idxs = hidden constant [0 x i32] zeroinitializer, align 8
 @subtarget_cloned_gv = hidden global i64* bitcast (i32 (i32)* @subtarget_cloned to i64*), align 8