Impl trace parsing, define top level approach

1 files changed, 208 insertions, 38 deletions

diff --git a/main.cpp b/main.cpp
index 168d25e..9aa4c44 100644
--- a/main.cpp
+++ b/main.cpp
@@ -1,46 +1,196 @@
 /* SPDX-License-Identifier: Unlicense
  */
 
+#define OPTPARSE_IMPLEMENTATION
+#define OPTPARSE_API static
+#include "optparse/optparse.h"
+
+#include <cassert>
 #include <cstdio>
 #include <cstdlib>
 #include <cstring>
 #include <cstdint>
 #include <cerrno>
-#define OPTPARSE_IMPLEMENTATION
-#define OPTPARSE_API static
-#include "optparse/optparse.h"
+#include <climits>
+
+/*
+ * We need to be able to modify output to place a mark when some jumping back
+ * is found, hence we should build output table instead of emitting asm right
+ * away into the output stream.
+ *
+ * I think the output should be an ordered map of decoded instructions. When the
+ * output is built according to the map we must walk through all the binary file
+ * again alongside with the output map and emit the final output right into the
+ * output stream.
+ *
+ * Trace data parser is needed. Maybe just using atol(3) will be ok.
+ */
 
 constexpr size_t kInstructionSizeStepBytes = 2;
 
-static int M68kDisasm(FILE *input_fd, FILE *output_fd, FILE *trace_fd)
+struct DataBuffer {
+    static constexpr size_t kInitialSize = 4 * 1024;
+    uint8_t *buffer{new uint8_t[kInitialSize]};
+    size_t buffer_size{kInitialSize};
+    size_t occupied_size{};
+    void Expand(size_t new_size) {
+        if (new_size <= buffer_size) {
+            return;
+        }
+        uint8_t *new_buffer{new uint8_t[new_size]};
+        assert(new_buffer);
+        memcpy(new_buffer, buffer, occupied_size);
+        delete [] buffer;
+        buffer = new_buffer;
+    }
+    ~DataBuffer() {
+        delete [] buffer;
+        buffer = nullptr;
+        buffer_size = 0;
+        occupied_size = 0;
+    }
+};
+
+enum class TracedNodeType {
+    kInstruction,
+    kData,
+};
+
+class DisasmMap {
+public:
+    // Returns true if node inserted, false if node already exist and has not
+    // been changed
+    bool InsertTracedNode(unsigned long offset, TracedNodeType);
+    // This function disassembles everything that has been traced
+    void DisasmAll(const DataBuffer &code);
+};
+
+bool DisasmMap::InsertTracedNode(unsigned long offset, TracedNodeType type)
+{
+    (void) offset;
+    (void) type;
+    // TODO
+    return true;
+}
+
+void DisasmMap::DisasmAll(const DataBuffer &code)
+{
+    (void) code;
+    // TODO
+}
+
+static void RenderDisassembly(FILE *output, const DisasmMap &disasm_map, const DataBuffer &code)
+{
+    (void) disasm_map;
+    (void) code;
+    (void) output;
+    // TODO
+}
+
+static void ParseTraceData(DisasmMap &disasm_map, const DataBuffer &trace_data)
+{
+    // FIXME make a full blown parser with various radixes support and different
+    // trace types support
+    bool parse = true;
+    for (size_t i = 0; i < trace_data.occupied_size; i++) {
+        if (trace_data.buffer[i] == '\n' || trace_data.buffer[i] == '\r') {
+            parse = true;
+        } else if (parse) {
+            errno = 0;
+            char *startptr = reinterpret_cast<char *>(trace_data.buffer + i);
+            char *endptr = startptr;
+            const long offset = strtol(startptr, &endptr, 16);
+            if ((offset == LONG_MAX || offset == LONG_MIN) && errno == ERANGE) {
+                // Error, just skip
+            } else if (startptr == endptr) {
+                // Error, just skip
+            } else {
+                // Valid value
+                disasm_map.InsertTracedNode(offset, TracedNodeType::kInstruction);
+                // TODO remove debug log
+                frintf(stderr, "[%zu] InsertTracedNode(%lu, kInstruction)\n", i, offset);
+            }
+            if (startptr != endptr) {
+                i += endptr - startptr - 1;
+            }
+            parse = false;
+        }
+    }
+}
+
+static size_t ReadFromStream(DataBuffer &db, FILE *stream)
 {
-    (void) input_fd;
-    (void) output_fd;
-    (void) trace_fd;
-    uint8_t instruction[100]{};
+    assert(db.buffer && db.buffer_size >= db.kInitialSize);
+    while (1) {
+        const size_t read_size = db.buffer_size - db.occupied_size;
+        const size_t fread_ret = fread(
+                db.buffer + db.occupied_size, sizeof(*db.buffer), read_size, stream);
+        db.occupied_size += fread_ret;
+        if (fread_ret >= db.buffer_size) {
+            assert(fread_ret == db.buffer_size);
+            db.Expand(db.buffer_size * 2);
+        } else {
+            const int err = errno;
+            if (feof(stream)) {
+                break;
+            } else if (ferror(stream)) {
+                fprintf(stderr, "ReadFromStream: fread(%zu): Error (%d): \"%s\"\n", read_size, err, strerror(err));
+                return EXIT_FAILURE;
+            } else if (db.buffer_size == db.occupied_size) {
+                db.Expand(db.buffer_size * 2);
+            } else {
+                assert (false);
+            }
+        }
+    }
+    return db.occupied_size;
+}
+
+static int M68kDisasmByTrace(FILE *input_stream, FILE *output_stream, FILE *trace_stream)
+{
+    // Read machine code into buffer
+    DataBuffer code{};
+    assert(ReadFromStream(code, input_stream));
+    // Read trace file into buffer
+    DataBuffer trace_data{};
+    assert(ReadFromStream(trace_data, trace_stream));
+    // Parse trace file into map
+    DisasmMap disasm_map{};
+    ParseTraceData(disasm_map, trace_data);
+    // Disasm into output map
+    disasm_map.DisasmAll(code);
+    // Print output into output_stream
+    RenderDisassembly(output_stream, disasm_map, code);
+    return 0;
+}
+
+static int M68kDisasmAll(FILE *input_stream, FILE *output_stream)
+{
+    uint8_t instruction[2]{};
     const size_t read_size = kInstructionSizeStepBytes;
     while (1) {
-        const size_t fread_ret = fread(instruction, 1, read_size, input_fd);
-        if (fread_ret <= 0) {
-            if (feof(input_fd)) {
+        const size_t fread_ret = fread(instruction, 1, read_size, input_stream);
+        if (fread_ret == 0) {
+            const int err = errno;
+            if (feof(input_stream)) {
                 break;
             } else {
-                fprintf(stderr, "Error reading: %s", strerror(errno));
+                fprintf(stderr, "ReadFromStream: fread(%zu): Error (%d): \"%s\"\n", read_size, err, strerror(err));
                 return EXIT_FAILURE;
             }
         }
-        fprintf(stdout, "  .short 0x%02x%02x\n", instruction[0], instruction[1]);
+        fprintf(output_stream, "  .short 0x%02x%02x\n", instruction[0], instruction[1]);
     }
     return 0;
 }
 
-static void PrintUsage(FILE *fd, const char *argv0)
+static void PrintUsage(FILE *stream, const char *argv0)
 {
-    fprintf(fd, "Usage: %s [options] [<input-file-name>]\n", argv0);
-    fprintf(fd, "  -h, --help,           Show this message\n");
-    fprintf(fd, "  -o, --output,         Where to write disassembly to (stdout if not set)\n");
-    fprintf(fd, "  -t, --pc-trace,       File containing PC trace\n");
-    fprintf(fd, "  <input_file_name>     Binary file with machine code (stdin if not set)\n");
+    fprintf(stream, "Usage: %s [options] [<input-file-name>]\n", argv0);
+    fprintf(stream, "  -h, --help,           Show this message\n");
+    fprintf(stream, "  -o, --output,         Where to write disassembly to (stdout if not set)\n");
+    fprintf(stream, "  -t, --pc-trace,       File containing PC trace\n");
+    fprintf(stream, "  <input_file_name>     Binary file with machine code (stdin if not set)\n");
 }
 
 int main(int, char* argv[])
@@ -62,7 +212,7 @@ int main(int, char* argv[])
         switch (option) {
         case 'h':
             PrintUsage(stdout, argv[0]);
-            exit(EXIT_SUCCESS);
+            return EXIT_SUCCESS;
             break;
         case 'o':
             output_file_name = options.optarg;
@@ -71,8 +221,8 @@ int main(int, char* argv[])
             trace_file_name = options.optarg;
             break;
         case '?':
-            fprintf(stderr, "%s: %s\n", argv[0], options.errmsg);
-            exit(EXIT_FAILURE);
+            fprintf(stderr, "main: optparse_long: Error: \"%s\"\n", options.errmsg);
+            return EXIT_FAILURE;
         }
     }
     // Parse input file name
@@ -82,29 +232,49 @@ int main(int, char* argv[])
             input_file_name = arg;
         } else {
             fprintf(stderr, "error: too many free arguments provided\n");
-            exit(EXIT_FAILURE);
+            return EXIT_FAILURE;
+        }
+    }
+    // Open the files
+    FILE *input_stream = stdin;
+    FILE *output_stream = stdout;
+    FILE *trace_stream = nullptr;
+    if (input_file_name) {
+        input_stream = fopen(input_file_name, "r");
+        if (input_stream == nullptr) {
+            const int err = errno;
+            fprintf(stderr, "main: fopen(\"%s\", \"r\"): Error (%d): \"%s\"\n", input_file_name, err, strerror(err));
+            return EXIT_FAILURE;
+        }
+    }
+    if (output_file_name) {
+        output_stream = fopen(output_file_name, "w");
+        if (output_stream == nullptr) {
+            const int err = errno;
+            fprintf(stderr, "main: fopen(\"%s\", \"w\"): Error (%d): \"%s\"\n", output_file_name, err, strerror(err));
+            return EXIT_FAILURE;
         }
     }
-    // TODO remove debug
-    fprintf(stdout, "input_file_name=%s\n", input_file_name ? input_file_name : "<stdin>");
-    fprintf(stdout, "output_file_name=%s\n", output_file_name ? output_file_name : "<stdout>");
     if (trace_file_name) {
-        fprintf(stdout, "trace_file_name=%s\n", output_file_name);
+        trace_stream = fopen(trace_file_name, "r");
+        if (trace_stream == nullptr) {
+            const int err = errno;
+            fprintf(stderr, "main: fopen(\"%s\", \"r\"): Error (%d): \"%s\"\n", trace_file_name, err, strerror(err));
+            return EXIT_FAILURE;
+        }
     }
-    // Open the files
-    FILE *input_fd = stdin; // TODO open file
-    FILE *output_fd = stdout; // TODO open file
-    FILE *trace_fd = nullptr; // TODO open file
     // Run the program
-    const int ret = M68kDisasm(input_fd, output_fd, trace_fd);
-    if (trace_fd != nullptr) {
-        fclose(trace_fd);
+    const int ret = trace_stream
+        ? M68kDisasmByTrace(input_stream, output_stream, trace_stream)
+        : M68kDisasmAll(input_stream, output_stream);
+    if (trace_stream != nullptr) {
+        fclose(trace_stream);
     }
-    if (output_fd != stdout) {
-        fclose(output_fd);
+    if (output_stream != stdout) {
+        fclose(output_stream);
     }
-    if (input_fd != stdin) {
-        fclose(input_fd);
+    if (input_stream != stdin) {
+        fclose(input_stream);
     }
     return ret;
 }