Unified BUILD_BUG_ON and STATIC_ASSERT into STATIC_ASSERT.

src/main/build/build_config.h

@@ -20,8 +20,6 @@
 
 #pragma once
 
-#define BUILD_BUG_ON(condition) ((void)sizeof(char[1 - 2*!!(condition)]))
-
 #ifdef UNIT_TEST
 // make these visible to unit test
 #define STATIC_UNIT_TESTED

src/main/common/utils.h

@@ -59,7 +59,9 @@
 #endif
 
 #define STATIC_ASSERT(condition, name) \
-    typedef char assert_failed_ ## name [(condition) ? 1 : -1 ] __attribute__((unused))
+    enum { assert_failed_ ## name = sizeof(char [(condition) ? 1 : -1 ]) }
+// If it is decided to ditch the -Wpedantic build flag, this should be switched to:
+//    _Static_assert((condition), #name)
 
 
 #define BIT(x) (1 << (x))

src/main/config/config_eeprom.c

@@ -86,12 +86,12 @@ typedef struct {
 void initEEPROM(void)
 {
     // Verify that this architecture packs as expected.
-    BUILD_BUG_ON(offsetof(packingTest_t, byte) != 0);
-    BUILD_BUG_ON(offsetof(packingTest_t, word) != 1);
-    BUILD_BUG_ON(sizeof(packingTest_t) != 5);
+    STATIC_ASSERT(offsetof(packingTest_t, byte) == 0, byte_packing_test_failed);
+    STATIC_ASSERT(offsetof(packingTest_t, word) == 1, word_packing_test_failed);
+    STATIC_ASSERT(sizeof(packingTest_t) == 5, overall_packing_test_failed);
 
-    BUILD_BUG_ON(sizeof(configFooter_t) != 2);
-    BUILD_BUG_ON(sizeof(configRecord_t) != 6);
+    STATIC_ASSERT(sizeof(configFooter_t) == 2, footer_size_failed);
+    STATIC_ASSERT(sizeof(configRecord_t) == 6, record_size_failed);
 }
 
 bool isEEPROMVersionValid(void)

src/main/drivers/stm32f7xx_ll_ex.h

@@ -37,12 +37,12 @@ __STATIC_INLINE DMA_TypeDef *LL_EX_DMA_Stream_to_DMA(DMA_Stream_TypeDef *DMAx_St
 
 __STATIC_INLINE uint32_t LL_EX_DMA_Stream_to_Stream(DMA_Stream_TypeDef *DMAx_Streamy)
 {
+	STATIC_ASSERT(DMA1_Stream0_BASE - DMA1_BASE == sizeof(DMA_TypeDef), DMA_TypeDef_has_padding);
+	STATIC_ASSERT(DMA1_Stream1_BASE - DMA1_Stream0_BASE == sizeof(DMA_Stream_TypeDef), DMA_Stream_TypeDef_has_padding);
+
 	const size_t firstStreamOffset = sizeof(DMA_TypeDef);
 	const size_t streamSize = sizeof(DMA_Stream_TypeDef);
 
-	STATIC_ASSERT(DMA1_Stream0_BASE - DMA1_BASE == firstStreamOffset, DMA_TypeDef_has_padding);
-	STATIC_ASSERT(DMA1_Stream1_BASE - DMA1_Stream0_BASE == streamSize, DMA_Stream_TypeDef_has_padding);
-
 	return (((uint32_t) DMAx_Streamy & DMA_STREAM_MASK) - firstStreamOffset) / streamSize;
 }
 

src/main/flight/pid.c

@@ -236,7 +236,7 @@ static FAST_RAM_ZERO_INIT pt1Filter_t antiGravityThrottleLpf;
 
 void pidInitFilters(const pidProfile_t *pidProfile)
 {
-    BUILD_BUG_ON(FD_YAW != 2); // ensure yaw axis is 2
+    STATIC_ASSERT(FD_YAW == 2, FD_YAW_incorrect); // ensure yaw axis is 2
 
     if (targetPidLooptime == 0) {
         // no looptime set, so set all the filters to null

src/main/interface/msp.c

@@ -35,9 +35,10 @@
 #include "common/axis.h"
 #include "common/bitarray.h"
 #include "common/color.h"
+#include "common/huffman.h"
 #include "common/maths.h"
 #include "common/streambuf.h"
-#include "common/huffman.h"
+#include "common/utils.h"
 
 #include "config/config_eeprom.h"
 #include "config/feature.h"
@@ -338,7 +339,7 @@ enum compressionType_e {
 
 static void serializeDataflashReadReply(sbuf_t *dst, uint32_t address, const uint16_t size, bool useLegacyFormat, bool allowCompression)
 {
-    BUILD_BUG_ON(MSP_PORT_DATAFLASH_INFO_SIZE < 16);
+    STATIC_ASSERT(MSP_PORT_DATAFLASH_INFO_SIZE >= 16, MSP_PORT_DATAFLASH_INFO_SIZE_invalid);
 
     uint16_t readLen = size;
     const int bytesRemainingInBuf = sbufBytesRemaining(dst) - MSP_PORT_DATAFLASH_INFO_SIZE;
@@ -596,25 +597,27 @@ static bool mspCommonProcessOutCommand(uint8_t cmdMSP, sbuf_t *dst, mspPostProce
     }
 
     case MSP_VOLTAGE_METER_CONFIG:
-        // by using a sensor type and a sub-frame length it's possible to configure any type of voltage meter,
-        // e.g. an i2c/spi/can sensor or any sensor not built directly into the FC such as ESC/RX/SPort/SBus that has
-        // different configuration requirements.
-        BUILD_BUG_ON(VOLTAGE_SENSOR_ADC_VBAT != 0); // VOLTAGE_SENSOR_ADC_VBAT should be the first index,
-        sbufWriteU8(dst, MAX_VOLTAGE_SENSOR_ADC); // voltage meters in payload
-        for (int i = VOLTAGE_SENSOR_ADC_VBAT; i < MAX_VOLTAGE_SENSOR_ADC; i++) {
-            const uint8_t adcSensorSubframeLength = 1 + 1 + 1 + 1 + 1; // length of id, type, vbatscale, vbatresdivval, vbatresdivmultipler, in bytes
-            sbufWriteU8(dst, adcSensorSubframeLength); // ADC sensor sub-frame length
+        {
+            // by using a sensor type and a sub-frame length it's possible to configure any type of voltage meter,
+            // e.g. an i2c/spi/can sensor or any sensor not built directly into the FC such as ESC/RX/SPort/SBus that has
+            // different configuration requirements.
+            STATIC_ASSERT(VOLTAGE_SENSOR_ADC_VBAT == 0, VOLTAGE_SENSOR_ADC_VBAT_incorrect); // VOLTAGE_SENSOR_ADC_VBAT should be the first index
+            sbufWriteU8(dst, MAX_VOLTAGE_SENSOR_ADC); // voltage meters in payload
+            for (int i = VOLTAGE_SENSOR_ADC_VBAT; i < MAX_VOLTAGE_SENSOR_ADC; i++) {
+                const uint8_t adcSensorSubframeLength = 1 + 1 + 1 + 1 + 1; // length of id, type, vbatscale, vbatresdivval, vbatresdivmultipler, in bytes
+                sbufWriteU8(dst, adcSensorSubframeLength); // ADC sensor sub-frame length
 
-            sbufWriteU8(dst, voltageMeterADCtoIDMap[i]); // id of the sensor
-            sbufWriteU8(dst, VOLTAGE_SENSOR_TYPE_ADC_RESISTOR_DIVIDER); // indicate the type of sensor that the next part of the payload is for
+                sbufWriteU8(dst, voltageMeterADCtoIDMap[i]); // id of the sensor
+                sbufWriteU8(dst, VOLTAGE_SENSOR_TYPE_ADC_RESISTOR_DIVIDER); // indicate the type of sensor that the next part of the payload is for
 
-            sbufWriteU8(dst, voltageSensorADCConfig(i)->vbatscale);
-            sbufWriteU8(dst, voltageSensorADCConfig(i)->vbatresdivval);
-            sbufWriteU8(dst, voltageSensorADCConfig(i)->vbatresdivmultiplier);
+                sbufWriteU8(dst, voltageSensorADCConfig(i)->vbatscale);
+                sbufWriteU8(dst, voltageSensorADCConfig(i)->vbatresdivval);
+                sbufWriteU8(dst, voltageSensorADCConfig(i)->vbatresdivmultiplier);
+            }
+            // if we had any other voltage sensors, this is where we would output any needed configuration
         }
-        // if we had any other voltage sensors, this is where we would output any needed configuration
-        break;
 
+        break;
     case MSP_CURRENT_METER_CONFIG: {
         // the ADC and VIRTUAL sensors have the same configuration requirements, however this API reflects
         // that this situation may change and allows us to support configuration of any current sensor with

src/main/interface/settings.c

@@ -1124,5 +1124,5 @@ const clivalue_t valueTable[] = {
 const uint16_t valueTableEntryCount = ARRAYLEN(valueTable);
 
 void settingsBuildCheck() {
-    BUILD_BUG_ON(LOOKUP_TABLE_COUNT != ARRAYLEN(lookupTables));
+    STATIC_ASSERT(LOOKUP_TABLE_COUNT == ARRAYLEN(lookupTables), LOOKUP_TABLE_COUNT_incorrect);
 }

src/main/io/ledstrip.c

@@ -165,7 +165,7 @@ void pgResetFn_ledStripConfig(ledStripConfig_t *ledStripConfig)
     memset(ledStripConfig->ledConfigs, 0, LED_MAX_STRIP_LENGTH * sizeof(ledConfig_t));
     // copy hsv colors as default
     memset(ledStripConfig->colors, 0, ARRAYLEN(hsv) * sizeof(hsvColor_t));
-    BUILD_BUG_ON(LED_CONFIGURABLE_COLOR_COUNT < ARRAYLEN(hsv));
+    STATIC_ASSERT(LED_CONFIGURABLE_COLOR_COUNT >= ARRAYLEN(hsv), LED_CONFIGURABLE_COLOR_COUNT_invalid);
     for (unsigned colorIndex = 0; colorIndex < ARRAYLEN(hsv); colorIndex++) {
         ledStripConfig->colors[colorIndex] = hsv[colorIndex];
     }

src/main/io/osd.c

@@ -1095,7 +1095,7 @@ void osdInit(displayPort_t *osdDisplayPortToUse)
         return;
     }
 
-    BUILD_BUG_ON(OSD_POS_MAX != OSD_POS(31,31));
+    STATIC_ASSERT(OSD_POS_MAX == OSD_POS(31,31), OSD_POS_MAX_incorrect);
 
     osdDisplayPort = osdDisplayPortToUse;
 #ifdef USE_CMS

src/main/rx/rx_spi.c

@@ -63,7 +63,7 @@ static protocolSetRcDataFromPayloadFnPtr protocolSetRcDataFromPayload;
 
 STATIC_UNIT_TESTED uint16_t rxSpiReadRawRC(const rxRuntimeConfig_t *rxRuntimeConfig, uint8_t channel)
 {
-    BUILD_BUG_ON(NRF24L01_MAX_PAYLOAD_SIZE > RX_SPI_MAX_PAYLOAD_SIZE);
+    STATIC_ASSERT(NRF24L01_MAX_PAYLOAD_SIZE <= RX_SPI_MAX_PAYLOAD_SIZE, NRF24L01_MAX_PAYLOAD_SIZE_larger_than_RX_SPI_MAX_PAYLOAD_SIZE);
 
     if (channel >= rxRuntimeConfig->channelCount) {
         return 0;