feat(svm): initial sbfv2 work (#496)

* svm: initial sbfv2 work

* svm: format for the style guide

* address some comments

* svm.elf: address some review comments

* svm: verify the length of the `.text` section

* svm: don't check for internal functions if an external one was already found

* svm: clarify and fixup some behaviour arround the frame pointer

* svm: correct `safeSlice`

data/test-elfs/.gitignore

@@ -0,0 +1,2 @@
+*.bc
+*.o

data/test-elfs/bss_section.zig

@@ -0,0 +1,7 @@
+// NOTE: the value is 0 in order to get the symbol into .bss
+var x: u32 = 0;
+
+export fn entrypoint() u32 {
+    @as(*volatile u32, &x).* = 10;
+    return 0;
+}

data/test-elfs/data_section.zig

@@ -0,0 +1,6 @@
+var x: u32 = 42;
+
+export fn entrypoint() u32 {
+    @as(*volatile u32, &x).* = 10;
+    return 0;
+}

data/test-elfs/elf.ld

@@ -0,0 +1,26 @@
+PHDRS
+{
+  text PT_LOAD  ;
+  rodata PT_LOAD ;
+  data PT_LOAD ;
+  dynamic PT_DYNAMIC ;
+}
+ENTRY ( entrypoint )
+SECTIONS
+{
+  . = SIZEOF_HEADERS;
+  .text : { *(.text*) } :text
+  .rodata : { *(.rodata*) } :rodata
+  .data.rel.ro : { *(.data.rel.ro*) } :rodata
+  .dynamic : { *(.dynamic) } :dynamic
+  .dynsym : { *(.dynsym) } :data
+  .dynstr : { *(.dynstr) } :data
+  .rel.dyn : { *(.rel.dyn) } :data
+  .data : { *(.data*) } :data
+  .bss : { *(.bss*) } :data
+  /DISCARD/ : {
+      *(.eh_frame*)
+      *(.gnu.hash*)
+      *(.hash*)
+    }
+}

data/test-elfs/reloc_64_64.zig

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+export fn entrypoint() u64 {
+    return @intFromPtr(&entrypoint);
+}

data/test-elfs/reloc_64_relative.zig

@@ -0,0 +1,3 @@
+export fn entrypoint() u64 {
+    return @intFromPtr("entrypoint");
+}

data/test-elfs/reloc_64_relative_data.zig

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+const DATA = "hello";
+
+export fn entrypoint() u64 {
+    return @intFromPtr(&DATA);
+}

data/test-elfs/rodata_section.zig

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+const VAL_A: u64 = 41;
+const VAL_B: u64 = 42;
+const VAL_C: u64 = 43;
+
+export fn entrypoint() u64 {
+    return @as(*const volatile u64, &VAL_B).*;
+}

data/test-elfs/struct_func_pointer.zig

@@ -0,0 +1,17 @@
+const PubkeyLutEntry = extern struct {
+    fp: *const fn (u8) callconv(.C) u8,
+    key: u64,
+};
+
+fn f1(a: u8) callconv(.C) u8 {
+    return a + 1;
+}
+
+export const entry: PubkeyLutEntry linksection(".data.rel.ro") = .{
+    .fp = f1,
+    .key = 0x0102030405060708,
+};
+
+export fn entrypoint() u64 {
+    return entry.key;
+}

data/test-elfs/syscall_reloc_64_32.zig

@@ -0,0 +1,6 @@
+extern fn log(msg: [*]const u8, len: u64) void;
+
+export fn entrypoint() u64 {
+    log("foo\n", 4);
+    return 0;
+}

scripts/gen_svm_elfs.sh

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+#!/bin/bash
+
+CC="../toolchain/llvm/bin/clang"
+LD="../toolchain/llvm/bin/ld.lld"
+ZIG="zig"
+
+
+LD_FLAGS="-z notext -shared --Bdynamic --script data/test-elfs/elf.ld"
+C_BASE_FLAGS="-target sbf-solana-solana \
+    -fno-builtin \
+    -fPIC -fno-unwind-tables \
+    -fomit-frame-pointer -fno-exceptions \
+    -fno-asynchronous-unwind-tables \
+    -std=c23 \
+    -O2 \
+    -Werror \
+    -Wno-override-module"
+C_FLAGS="${C_BASE_FLAGS} -mcpu=v1"
+C_FLAGS_V2="${C_BASE_FLAGS} -mcpu=sbfv2"
+
+CC_V1="${CC} ${C_FLAGS}"
+CC_V2="${CC} ${C_FLAGS_V2}"
+
+LD_V1="${LD} ${LD_FLAGS}"
+LD_V2="${LD_V1} --section-start=.text=0x100000000"
+
+V1_FILES=(reloc_64_64 reloc_64_relative reloc_64_relative_data rodata_section)
+
+for ZIG_FILE in data/test-elfs/*.zig; do
+    BASE_NAME=$(basename "$ZIG_FILE" .zig)
+
+    $ZIG build-obj "$ZIG_FILE" -OReleaseSmall -fstrip -fno-emit-bin -femit-llvm-bc="data/test-elfs/${BASE_NAME}.bc"
+    $CC_V2 "data/test-elfs/${BASE_NAME}.bc" -c -o "data/test-elfs/${BASE_NAME}.o"
+    $LD_V2 "data/test-elfs/${BASE_NAME}.o" -o "data/test-elfs/${BASE_NAME}.so"
+
+    if [[ " ${V1_FILES[@]} " =~ " ${BASE_NAME} " ]]; then
+        $CC_V1 "data/test-elfs/${BASE_NAME}.bc" -c -o "data/test-elfs/${BASE_NAME}_sbpfv1.o"
+        $LD_V1 "data/test-elfs/${BASE_NAME}_sbpfv1.o" -o "data/test-elfs/${BASE_NAME}_sbpfv1.so"
+    fi
+done
+
+rm data/test-elfs/*.o
+rm data/test-elfs/*.bc