Move hard-coded values to constants.

Change all of the hard-coded config values to be defined constants.
Also make sure to use these constants in the usage output.

Bug: 26739265
Change-Id: I597a6d71279a2df9cc7e98c42ac70224261bac99

1 files changed, 55 insertions, 31 deletions

diff --git a/libc/malloc_debug/Config.cpp b/libc/malloc_debug/Config.cpp
index ce83aa4bb..4586fda3b 100644
--- a/libc/malloc_debug/Config.cpp
+++ b/libc/malloc_debug/Config.cpp
@@ -44,6 +44,26 @@
 #include "Config.h"
 #include "debug_log.h"
 
+// Config constants
+static constexpr uint8_t DEFAULT_FILL_ALLOC_VALUE = 0xeb;
+static constexpr uint8_t DEFAULT_FILL_FREE_VALUE = 0xef;
+
+static constexpr uint8_t DEFAULT_FRONT_GUARD_VALUE = 0xaa;
+static constexpr uint8_t DEFAULT_REAR_GUARD_VALUE = 0xbb;
+
+// Used as the default for all guard values.
+static constexpr size_t DEFAULT_GUARD_BYTES = 32;
+static constexpr size_t MAX_GUARD_BYTES = 16384;
+
+static constexpr size_t DEFAULT_BACKTRACE_FRAMES = 16;
+static constexpr size_t MAX_BACKTRACE_FRAMES = 256;
+
+static constexpr size_t DEFAULT_EXPAND_BYTES = 16;
+static constexpr size_t MAX_EXPAND_BYTES = 16384;
+
+static constexpr size_t DEFAULT_FREE_TRACK_ALLOCATIONS = 100;
+static constexpr size_t MAX_FREE_TRACK_ALLOCATIONS = 16384;
+
 struct Feature {
   Feature(std::string name, size_t default_value, size_t min_value, size_t max_value,
           uint64_t option, size_t* value, bool* config, bool combo_option)
@@ -72,12 +92,6 @@ class PropertyParser {
 
   void LogUsage();
 
-  static constexpr uint8_t DEFAULT_FILL_ALLOC_VALUE = 0xeb;
-  static constexpr uint8_t DEFAULT_FILL_FREE_VALUE = 0xef;
-
-  static constexpr uint8_t DEFAULT_FRONT_GUARD_VALUE = 0xaa;
-  static constexpr uint8_t DEFAULT_REAR_GUARD_VALUE = 0xbb;
-
  private:
   const char* cur_ = nullptr;
 
@@ -144,28 +158,31 @@ void PropertyParser::LogUsage() {
   error_log("  front_guard[=XX]");
   error_log("    Enables a front guard on all allocations. If XX is set");
   error_log("    it sets the number of bytes in the guard. The default is");
-  error_log("    32 bytes.");
+  error_log("    %zu bytes, the max bytes is %zu.", DEFAULT_GUARD_BYTES, MAX_GUARD_BYTES);
   error_log("");
   error_log("  rear_guard[=XX]");
   error_log("    Enables a rear guard on all allocations. If XX is set");
   error_log("    it sets the number of bytes in the guard. The default is");
-  error_log("    32 bytes.");
+  error_log("    %zu bytes, the max bytes is %zu.", DEFAULT_GUARD_BYTES, MAX_GUARD_BYTES);
   error_log("");
   error_log("  guard[=XX]");
   error_log("    Enables both a front guard and a rear guard on all allocations.");
   error_log("    If XX is set it sets the number of bytes in both guards.");
-  error_log("    The default is 32 bytes.");
+  error_log("    The default is %zu bytes, the max bytes is %zu.",
+            DEFAULT_GUARD_BYTES, MAX_GUARD_BYTES);
   error_log("");
   error_log("  backtrace[=XX]");
   error_log("    Enable capturing the backtrace at the point of allocation.");
   error_log("    If XX is set it sets the number of backtrace frames.");
-  error_log("    The default is 16 frames.");
+  error_log("    The default is %zu frames, the max number of frames is %zu.",
+            DEFAULT_BACKTRACE_FRAMES, MAX_BACKTRACE_FRAMES);
   error_log("");
   error_log("  backtrace_enable_on_signal[=XX]");
   error_log("    Enable capturing the backtrace at the point of allocation.");
   error_log("    The backtrace capture is not enabled until the process");
   error_log("    receives a signal. If XX is set it sets the number of backtrace");
-  error_log("    frames. The default is 16 frames.");
+  error_log("    frames. The default is %zu frames, the max number of frames is %zu.",
+            DEFAULT_BACKTRACE_FRAMES, MAX_BACKTRACE_FRAMES);
   error_log("");
   error_log("  fill_on_alloc[=XX]");
   error_log("    On first allocation, fill with the value 0x%02x.", DEFAULT_FILL_ALLOC_VALUE);
@@ -188,7 +205,8 @@ void PropertyParser::LogUsage() {
   error_log("  expand_alloc[=XX]");
   error_log("    Allocate an extra number of bytes for every allocation call.");
   error_log("    If XX is set, that is the number of bytes to expand the");
-  error_log("    allocation by. The default is 16 bytes.");
+  error_log("    allocation by. The default is %zu bytes, the max bytes is %zu.",
+            DEFAULT_EXPAND_BYTES, MAX_EXPAND_BYTES);
   error_log("");
   error_log("  free_track[=XX]");
   error_log("    When a pointer is freed, do not free the memory right away.");
@@ -197,14 +215,17 @@ void PropertyParser::LogUsage() {
   error_log("    allocations exceeds the XX amount. When the program terminates,");
   error_log("    the rest of these allocations are verified. When this option is");
   error_log("    enabled, it automatically records the backtrace at the time of the free.");
-  error_log("    The default is to record 100 allocations.");
+  error_log("    The default is to record %zu allocations, the max allocations",
+            DEFAULT_FREE_TRACK_ALLOCATIONS);
+  error_log("    to record is %zu.", MAX_FREE_TRACK_ALLOCATIONS);
   error_log("");
   error_log("  free_track_backtrace_num_frames[=XX]");
   error_log("    This option only has meaning if free_track is set. This indicates");
   error_log("    how many backtrace frames to capture when an allocation is freed.");
   error_log("    If XX is set, that is the number of frames to capture. If XX");
   error_log("    is set to zero, then no backtrace will be captured.");
-  error_log("    The default is to record 16 frames.");
+  error_log("    The default is to record %zu frames, the max number of frames is %zu.",
+            DEFAULT_BACKTRACE_FRAMES, MAX_BACKTRACE_FRAMES);
   error_log("");
   error_log("  leak_track");
   error_log("    Enable the leak tracking of memory allocations.");
@@ -248,10 +269,10 @@ bool Config::SetFromProperties() {
   }
 
   // Initialize a few default values.
-  fill_alloc_value = PropertyParser::DEFAULT_FILL_ALLOC_VALUE;
-  fill_free_value = PropertyParser::DEFAULT_FILL_FREE_VALUE;
-  front_guard_value = PropertyParser::DEFAULT_FRONT_GUARD_VALUE;
-  rear_guard_value = PropertyParser::DEFAULT_REAR_GUARD_VALUE;
+  fill_alloc_value = DEFAULT_FILL_ALLOC_VALUE;
+  fill_free_value = DEFAULT_FILL_FREE_VALUE;
+  front_guard_value = DEFAULT_FRONT_GUARD_VALUE;
+  rear_guard_value = DEFAULT_REAR_GUARD_VALUE;
   backtrace_signal = SIGRTMIN + 10;
   free_track_backtrace_num_frames = 16;
 
@@ -260,19 +281,22 @@ bool Config::SetFromProperties() {
 
   // Supported features:
   const Feature features[] = {
-    Feature("guard", 32, 1, 16384, 0, nullptr, nullptr, true),
+    Feature("guard", DEFAULT_GUARD_BYTES, 1, MAX_GUARD_BYTES, 0, nullptr, nullptr, true),
     // Enable front guard. Value is the size of the guard.
-    Feature("front_guard", 32, 1, 16384, FRONT_GUARD, &this->front_guard_bytes, nullptr, true),
+    Feature("front_guard", DEFAULT_GUARD_BYTES, 1, MAX_GUARD_BYTES, FRONT_GUARD,
+            &this->front_guard_bytes, nullptr, true),
     // Enable end guard. Value is the size of the guard.
-    Feature("rear_guard", 32, 1, 16384, REAR_GUARD, &this->rear_guard_bytes, nullptr, true),
+    Feature("rear_guard", DEFAULT_GUARD_BYTES, 1, MAX_GUARD_BYTES, REAR_GUARD,
+            &this->rear_guard_bytes, nullptr, true),
 
     // Enable logging the backtrace on allocation. Value is the total
     // number of frames to log.
-    Feature("backtrace", 16, 1, 256, BACKTRACE | TRACK_ALLOCS, &this->backtrace_frames,
-            &this->backtrace_enabled, false),
+    Feature("backtrace", DEFAULT_BACKTRACE_FRAMES, 1, MAX_BACKTRACE_FRAMES,
+            BACKTRACE | TRACK_ALLOCS, &this->backtrace_frames, &this->backtrace_enabled, false),
     // Enable gathering backtrace values on a signal.
-    Feature("backtrace_enable_on_signal", 16, 1, 256, BACKTRACE | TRACK_ALLOCS,
-            &this->backtrace_frames, &this->backtrace_enable_on_signal, false),
+    Feature("backtrace_enable_on_signal", DEFAULT_BACKTRACE_FRAMES, 1, MAX_BACKTRACE_FRAMES,
+            BACKTRACE | TRACK_ALLOCS, &this->backtrace_frames, &this->backtrace_enable_on_signal,
+            false),
 
     Feature("fill", SIZE_MAX, 1, SIZE_MAX, 0, nullptr, nullptr, true),
     // Fill the allocation with an arbitrary pattern on allocation.
@@ -287,18 +311,18 @@ bool Config::SetFromProperties() {
 
     // Expand the size of every alloc by this number bytes. Value is
     // the total number of bytes to expand every allocation by.
-    Feature ("expand_alloc", 16, 1, 16384, EXPAND_ALLOC, &this->expand_alloc_bytes,
-             nullptr, false),
+    Feature ("expand_alloc", DEFAULT_EXPAND_BYTES, 1, MAX_EXPAND_BYTES, EXPAND_ALLOC,
+             &this->expand_alloc_bytes, nullptr, false),
 
     // Keep track of the freed allocations and verify at a later date
     // that they have not been used. Turning this on, also turns on
     // fill on free.
-    Feature("free_track", 100, 1, 16384, FREE_TRACK | FILL_ON_FREE, &this->free_track_allocations,
-            nullptr, false),
+    Feature("free_track", DEFAULT_FREE_TRACK_ALLOCATIONS, 1, MAX_FREE_TRACK_ALLOCATIONS,
+            FREE_TRACK | FILL_ON_FREE, &this->free_track_allocations, nullptr, false),
     // Number of backtrace frames to keep when free_track is enabled. If this
     // value is set to zero, no backtrace will be kept.
-    Feature("free_track_backtrace_num_frames", 16, 0, 256, 0,
-            &this->free_track_backtrace_num_frames, nullptr, false),
+    Feature("free_track_backtrace_num_frames", DEFAULT_BACKTRACE_FRAMES,
+            0, MAX_BACKTRACE_FRAMES, 0, &this->free_track_backtrace_num_frames, nullptr, false),
 
     // Enable printing leaked allocations.
     Feature("leak_track", 0, 0, 0, LEAK_TRACK | TRACK_ALLOCS, nullptr, nullptr, false),