[FL-2627] Flipper applications: SDK, build and debug system (#1387)

* Added support for running applications from SD card (FAPs - Flipper Application Packages)
* Added plugin_dist target for fbt to build FAPs
* All apps of type FlipperAppType.EXTERNAL and FlipperAppType.PLUGIN are built as FAPs by default
* Updated VSCode configuration for new fbt features - re-deploy stock configuration to use them
* Added debugging support for FAPs with fbt debug & VSCode
* Added public firmware API with automated versioning

Co-authored-by: hedger <hedger@users.noreply.github.com>
Co-authored-by: SG <who.just.the.doctor@gmail.com>
Co-authored-by: あく <alleteam@gmail.com>

applications/main/fap_loader/elf_cpp/compilesort.hpp

@@ -0,0 +1,111 @@
+/**
+ * Implementation of compile-time sort for symbol table entries.
+ */
+
+#pragma once
+
+#include <iterator>
+#include <array>
+
+namespace cstd {
+
+template <typename RAIt>
+constexpr RAIt next(RAIt it, typename std::iterator_traits<RAIt>::difference_type n = 1) {
+    return it + n;
+}
+
+template <typename RAIt>
+constexpr auto distance(RAIt first, RAIt last) {
+    return last - first;
+}
+
+template <class ForwardIt1, class ForwardIt2>
+constexpr void iter_swap(ForwardIt1 a, ForwardIt2 b) {
+    auto temp = std::move(*a);
+    *a = std::move(*b);
+    *b = std::move(temp);
+}
+
+template <class InputIt, class UnaryPredicate>
+constexpr InputIt find_if_not(InputIt first, InputIt last, UnaryPredicate q) {
+    for(; first != last; ++first) {
+        if(!q(*first)) {
+            return first;
+        }
+    }
+    return last;
+}
+
+template <class ForwardIt, class UnaryPredicate>
+constexpr ForwardIt partition(ForwardIt first, ForwardIt last, UnaryPredicate p) {
+    first = cstd::find_if_not(first, last, p);
+    if(first == last) return first;
+
+    for(ForwardIt i = cstd::next(first); i != last; ++i) {
+        if(p(*i)) {
+            cstd::iter_swap(i, first);
+            ++first;
+        }
+    }
+    return first;
+}
+
+}
+
+template <class RAIt, class Compare = std::less<> >
+constexpr void quick_sort(RAIt first, RAIt last, Compare cmp = Compare{}) {
+    auto const N = cstd::distance(first, last);
+    if(N <= 1) return;
+    auto const pivot = *cstd::next(first, N / 2);
+    auto const middle1 =
+        cstd::partition(first, last, [=](auto const& elem) { return cmp(elem, pivot); });
+    auto const middle2 =
+        cstd::partition(middle1, last, [=](auto const& elem) { return !cmp(pivot, elem); });
+    quick_sort(first, middle1, cmp); // assert(std::is_sorted(first, middle1, cmp));
+    quick_sort(middle2, last, cmp); // assert(std::is_sorted(middle2, last, cmp));
+}
+
+template <typename Range>
+constexpr auto sort(Range&& range) {
+    quick_sort(std::begin(range), std::end(range));
+    return range;
+}
+
+template <typename V, typename... T>
+constexpr auto array_of(T&&... t) -> std::array<V, sizeof...(T)> {
+    return {{std::forward<T>(t)...}};
+}
+
+template <typename T, typename... N>
+constexpr auto my_make_array(N&&... args) -> std::array<T, sizeof...(args)> {
+    return {std::forward<N>(args)...};
+}
+
+namespace traits {
+template <typename T, typename... Ts>
+struct array_type {
+    using type = T;
+};
+
+template <typename T, typename... Ts>
+static constexpr bool are_same_type() {
+    return std::conjunction_v<std::is_same<T, Ts>...>;
+}
+
+}
+
+template <typename... T>
+constexpr auto create_array(const T&&... values) {
+    using array_type = typename traits::array_type<T...>::type;
+    static_assert(sizeof...(T) > 0, "an array must have at least one element");
+    static_assert(traits::are_same_type<T...>(), "all elements must have same type");
+    return std::array<array_type, sizeof...(T)>{values...};
+}
+
+template <typename T, typename... Ts>
+constexpr auto create_array_t(const Ts&&... values) {
+    using array_type = T;
+    static_assert(sizeof...(Ts) > 0, "an array must have at least one element");
+    static_assert(traits::are_same_type<Ts...>(), "all elements must have same type");
+    return std::array<array_type, sizeof...(Ts)>{static_cast<T>(values)...};
+}

applications/main/fap_loader/elf_cpp/elf_hashtable.cpp

@@ -0,0 +1,48 @@
+#include "compilesort.hpp"
+#include "elf_hashtable.h"
+#include "elf_hashtable_entry.h"
+#include "elf_hashtable_checks.hpp"
+
+#include <array>
+#include <algorithm>
+
+/* Generated table */
+#include <symbols.h>
+
+#define TAG "elf_hashtable"
+
+static_assert(!has_hash_collisions(elf_api_table), "Detected API method hash collision!");
+
+/**
+ * Get function address by function name
+ * @param name function name
+ * @param address output for function address
+ * @return true if the table contains a function
+ */
+
+bool elf_resolve_from_hashtable(const char* name, Elf32_Addr* address) {
+    bool result = false;
+    uint32_t gnu_sym_hash = elf_gnu_hash(name);
+
+    sym_entry key = {
+        .hash = gnu_sym_hash,
+        .address = 0,
+    };
+
+    auto find_res = std::lower_bound(elf_api_table.cbegin(), elf_api_table.cend(), key);
+    if((find_res == elf_api_table.cend() || (find_res->hash != gnu_sym_hash))) {
+        FURI_LOG_W(TAG, "Cant find symbol '%s' (hash %x)!", name, gnu_sym_hash);
+        result = false;
+    } else {
+        result = true;
+        *address = find_res->address;
+    }
+
+    return result;
+}
+
+const ElfApiInterface hashtable_api_interface = {
+    .api_version_major = (elf_api_version >> 16),
+    .api_version_minor = (elf_api_version & 0xFFFF),
+    .resolver_callback = &elf_resolve_from_hashtable,
+};

applications/main/fap_loader/elf_cpp/elf_hashtable.h

@@ -0,0 +1,14 @@
+#pragma once
+#include <stdint.h>
+
+#include <flipper_application/elf/elf_api_interface.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+extern const ElfApiInterface hashtable_api_interface;
+
+#ifdef __cplusplus
+}
+#endif

applications/main/fap_loader/elf_cpp/elf_hashtable_checks.hpp

@@ -0,0 +1,18 @@
+/**
+ * Check for multiple entries with the same hash value at compilation time.
+ */
+
+#pragma once
+#include <array>
+#include "elf_hashtable_entry.h"
+
+template <std::size_t N>
+constexpr bool has_hash_collisions(const std::array<sym_entry, N> api_methods) {
+    for(std::size_t i = 0; i < (N - 1); ++i) {
+        if(api_methods[i].hash == api_methods[i + 1].hash) {
+            return true;
+        }
+    }
+
+    return false;
+}

applications/main/fap_loader/elf_cpp/elf_hashtable_entry.h

@@ -0,0 +1,41 @@
+#pragma once
+#include <stdint.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct sym_entry {
+    uint32_t hash;
+    uint32_t address;
+};
+
+#ifdef __cplusplus
+}
+
+#include <array>
+#include <algorithm>
+
+#define API_METHOD(x, ret_type, args_type)                                                     \
+    sym_entry {                                                                                \
+        .hash = elf_gnu_hash(#x), .address = (uint32_t)(static_cast<ret_type(*) args_type>(x)) \
+    }
+
+#define API_VARIABLE(x, var_type)                              \
+    sym_entry {                                                \
+        .hash = elf_gnu_hash(#x), .address = (uint32_t)(&(x)), \
+    }
+
+constexpr bool operator<(const sym_entry& k1, const sym_entry& k2) {
+    return k1.hash < k2.hash;
+}
+
+constexpr uint32_t elf_gnu_hash(const char* s) {
+    uint32_t h = 0x1505;
+    for(unsigned char c = *s; c != '\0'; c = *++s) {
+        h = (h << 5) + h + c;
+    }
+    return h;
+}
+
+#endif