baremetal: Add GCC toolchain support to stm32f103 example

Change-Id: Ida327f4ef61de58040bd949ec71b2375cbe3f4b0
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>

4 files changed, 380 insertions, 1 deletions

diff --git a/examples/baremetal/stm32f103/greenblink/README.md b/examples/baremetal/stm32f103/greenblink/README.md
index 87b5a709f..652ab7ec2 100644
--- a/examples/baremetal/stm32f103/greenblink/README.md
+++ b/examples/baremetal/stm32f103/greenblink/README.md
@@ -5,4 +5,5 @@ LED on the board.
 
 The following toolchains are supported:
 
+  * GNU Arm Embedded Toolchain
   * KEIL Microcontroller Development Kit
diff --git a/examples/baremetal/stm32f103/greenblink/gcc/flash.ld b/examples/baremetal/stm32f103/greenblink/gcc/flash.ld
new file mode 100644
index 000000000..3fe5c1563
--- /dev/null
+++ b/examples/baremetal/stm32f103/greenblink/gcc/flash.ld
@@ -0,0 +1,172 @@
+/****************************************************************************
+**
+** Copyright (C) 2020 Denis Shienkov <denis.shienkov@gmail.com>
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the examples of Qbs.
+**
+** $QT_BEGIN_LICENSE:BSD$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** BSD License Usage
+** Alternatively, you may use this file under the terms of the BSD license
+** as follows:
+**
+** "Redistribution and use in source and binary forms, with or without
+** modification, are permitted provided that the following conditions are
+** met:
+**   * Redistributions of source code must retain the above copyright
+**     notice, this list of conditions and the following disclaimer.
+**   * Redistributions in binary form must reproduce the above copyright
+**     notice, this list of conditions and the following disclaimer in
+**     the documentation and/or other materials provided with the
+**     distribution.
+**   * Neither the name of The Qt Company Ltd nor the names of its
+**     contributors may be used to endorse or promote products derived
+**     from this software without specific prior written permission.
+**
+**
+** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+/* Entry point (defined in assembled file). */
+ENTRY(reset_handler)
+
+/* End of RAM, it is the user mode stack pointer address. */
+_end_of_stack = 0x20005000;
+
+/* Generate a link error if heap and stack don't fit into RAM. */
+_size_of_heap = 0x200;  /* Required amount of heap. */
+_size_of_stack = 0x400; /* Required amount of stack. */
+
+MEMORY {
+    RAM (xrw)   : ORIGIN = 0x20000000, LENGTH = 20K
+    FLASH (rx)  : ORIGIN = 0x8000000, LENGTH = 64K
+}
+
+SECTIONS {
+    /* The vectors table goes into FLASH. */
+    .isr_vector : {
+        . = ALIGN(4);
+        KEEP(*(.isr_vector)) /* Startup code. */
+        . = ALIGN(4);
+    } > FLASH
+
+    /* The program code and other data goes into FLASH. */
+    .text : {
+        . = ALIGN(4);
+        *(.text)
+        *(.text*)
+        *(.glue_7)                    /* Glue arm to thumb code. */
+        *(.glue_7t)                   /* Glue thumb to arm code. */
+        *(.eh_frame)
+        KEEP(*(.init))
+        KEEP(*(.fini))
+        . = ALIGN(4);
+        _end_of_text_section = .;     /* Export global symbol at end of code. */
+    } > FLASH
+
+    /* Constant data goes into FLASH. */
+    .rodata : {
+        . = ALIGN(4);
+        *(.rodata)
+        *(.rodata*)
+        . = ALIGN(4);
+    } > FLASH
+
+    .ARM.extab : {
+        *(.ARM.extab* .gnu.linkonce.armextab.*)
+    } > FLASH
+
+    .ARM : {
+        __exidx_start = .;
+        *(.ARM.exidx*)
+        __exidx_end = .;
+    } > FLASH
+
+    .preinit_array : {
+        PROVIDE_HIDDEN(__preinit_array_start = .);
+        KEEP(*(.preinit_array*))
+        PROVIDE_HIDDEN(__preinit_array_end = .);
+    } > FLASH
+
+    .init_array : {
+        PROVIDE_HIDDEN(__init_array_start = .);
+        KEEP(*(SORT(.init_array.*)))
+        KEEP(*(.init_array*))
+        PROVIDE_HIDDEN(__init_array_end = .);
+    } > FLASH
+
+    .fini_array : {
+        PROVIDE_HIDDEN(__fini_array_start = .);
+        KEEP(*(SORT(.fini_array.*)))
+        KEEP(*(.fini_array*))
+        PROVIDE_HIDDEN(__fini_array_end = .);
+    } > FLASH
+
+    _start_of_init_data_section = LOADADDR(.data);
+
+    /* Initialized data sections goes into RAM, load LMA copy after code. */
+    .data : {
+        . = ALIGN(4);
+        _start_of_data_section = .;   /* Export global symbol at data start. */
+        *(.data)
+        *(.data*)
+        . = ALIGN(4);
+        _end_of_data_section = .;     /* Export global symbol at data end. */
+    } > RAM AT > FLASH
+
+    /* Uninitialized data section. */
+    . = ALIGN(4);
+    .bss : {
+        /* This is used by the startup in order to initialize the .bss secion. */
+        _start_of_bss_section = .;    /* Export global symbol at bss start. */
+        __bss_start__ = _start_of_bss_section;
+        *(.bss)
+        *(.bss*)
+        *(COMMON)
+        . = ALIGN(4);
+        _end_of_bss_section = .;      /* Export global symbol at bss end. */
+        __bss_end__ = _end_of_bss_section;
+    } > RAM
+
+    /* Used to check that there is enough RAM left. */
+    ._user_heap_stack : {
+        . = ALIGN(4);
+        PROVIDE(end = .);
+        PROVIDE(_end = .);
+        . = . + _size_of_heap;
+        . = . + _size_of_stack;
+        . = ALIGN(4);
+    } > RAM
+
+    /* Remove information from the standard libraries. */
+    /DISCARD/ : {
+        libc.a ( * )
+        libm.a ( * )
+        libgcc.a ( * )
+    }
+
+    .ARM.attributes 0 : {
+        *(.ARM.attributes)
+    }
+}
diff --git a/examples/baremetal/stm32f103/greenblink/gcc/startup.s b/examples/baremetal/stm32f103/greenblink/gcc/startup.s
new file mode 100644
index 000000000..5bb262f16
--- /dev/null
+++ b/examples/baremetal/stm32f103/greenblink/gcc/startup.s
@@ -0,0 +1,177 @@
+/****************************************************************************
+**
+** Copyright (C) 2020 Denis Shienkov <denis.shienkov@gmail.com>
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the examples of Qbs.
+**
+** $QT_BEGIN_LICENSE:BSD$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** BSD License Usage
+** Alternatively, you may use this file under the terms of the BSD license
+** as follows:
+**
+** "Redistribution and use in source and binary forms, with or without
+** modification, are permitted provided that the following conditions are
+** met:
+**   * Redistributions of source code must retain the above copyright
+**     notice, this list of conditions and the following disclaimer.
+**   * Redistributions in binary form must reproduce the above copyright
+**     notice, this list of conditions and the following disclaimer in
+**     the documentation and/or other materials provided with the
+**     distribution.
+**   * Neither the name of The Qt Company Ltd nor the names of its
+**     contributors may be used to endorse or promote products derived
+**     from this software without specific prior written permission.
+**
+**
+** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+.syntax unified
+.cpu cortex-m3
+.fpu softvfp
+.thumb
+
+// These symbols are exported from the linker script.
+.word _start_of_init_data_section
+.word _start_of_data_section
+.word _end_of_data_section
+.word _start_of_bss_section
+.word _end_of_bss_section
+
+.equ  _boot_ram, 0xF108F85F
+
+.section .text.reset_handler
+.weak reset_handler
+.type reset_handler, %function
+reset_handler:
+    // Copy the data segment initializers from flash to SRAM.
+    movs    r1, #0
+    b       _loop_copy_data_init
+_copy_data_init:
+    ldr     r3, =_start_of_init_data_section
+    ldr     r3, [r3, r1]
+    str     r3, [r0, r1]
+    adds    r1, r1, #4
+_loop_copy_data_init:
+    ldr     r0, =_start_of_data_section
+    ldr     r3, =_end_of_data_section
+    adds    r2, r0, r1
+    cmp     r2, r3
+    bcc     _copy_data_init
+    ldr r2, =_start_of_bss_section
+    b       _loop_fill_zero_bss
+
+    // Zero fill the bss segment.
+_fill_zero_bss:
+    movs    r3, #0
+    str     r3, [r2], #4
+_loop_fill_zero_bss:
+    ldr     r3, = _end_of_bss_section
+    cmp     r2, r3
+    bcc     _fill_zero_bss
+
+    // Call the static constructors.
+    bl      __libc_init_array
+
+    // Call the application entry point.
+    bl      main
+    bx      lr
+.size reset_handler, .-reset_handler
+
+// Define the empty vectors table.
+.section .isr_vector,"a",%progbits
+.type _vectors_table, %object
+.size _vectors_table, .-_vectors_table
+_vectors_table:
+    // Generic interrupts offset.
+    .word    _end_of_stack  // Initial stack pointer value.
+    .word    reset_handler  // Reset.
+    .word    0              // NMI.
+    .word    0              // Hard fault.
+    .word    0              // Memory management fault.
+    .word    0              // Bus fault.
+    .word    0              // Usage fault.
+    .word    0              // Reserved.
+    .word    0              // Reserved.
+    .word    0              // Reserved.
+    .word    0              // Reserved.
+    .word    0              // SVC.
+    .word    0              // Debug monitor.
+    .word    0              // Reserved.
+    .word    0              // PendSV.
+    .word    0              // SysTick.
+
+    // External interrupts offset.
+    .word    0              // Window watchdog.
+    .word    0              // PVD through EXTI Line detection.
+    .word    0              // Tamper and timestamps through the EXTI line.
+    .word    0              // RTC wakeup through the EXTI line.
+    .word    0              // FLASH.
+    .word    0              // RCC.
+    .word    0              // EXTI line0.
+    .word    0              // EXTI line1.
+    .word    0              // EXTI line2.
+    .word    0              // EXTI line3.
+    .word    0              // EXTI line4.
+    .word    0              // DMA1 stream 0.
+    .word    0              // DMA1 stream 1.
+    .word    0              // DMA1 stream 2.
+    .word    0              // DMA1 stream 3.
+    .word    0              // DMA1 stream 4.
+    .word    0              // DMA1 stream 5.
+    .word    0              // DMA1 stream 6.
+    .word    0              // ADC1/2.
+    .word    0              // USB HP/CAN1 TX.
+    .word    0              // USB LP / CAN1 RX0.
+    .word    0              // CAN1 RX1.
+    .word    0              // CAN1 SCE.
+    .word    0              // EXTI line [9:5]s.
+    .word    0              // TIM1 break.
+    .word    0              // TIM1 update.
+    .word    0              // TIM1 trigger and communication.
+    .word    0              // TIM1 capture compare.
+    .word    0              // TIM2.
+    .word    0              // TIM3.
+    .word    0              // TIM4.
+    .word    0              // I2C1 event.
+    .word    0              // I2C1 error.
+    .word    0              // I2C2 event.
+    .word    0              // I2C2 error.
+    .word    0              // SPI1.
+    .word    0              // SPI2.
+    .word    0              // USART1.
+    .word    0              // USART2.
+    .word    0              // USART3.
+    .word    0              // EXTI line [15:10]s.
+    .word    0              // RTC alarm.
+    .word    0              // USB wakeup.
+    .word    0
+    .word    0
+    .word    0
+    .word    0
+    .word    0
+    .word    0
+    .word    0
+    .word    _boot_ram      // Boot RAM mode for stm32f10x medium density devices.
diff --git a/examples/baremetal/stm32f103/greenblink/greenblink.qbs b/examples/baremetal/stm32f103/greenblink/greenblink.qbs
index 13f5a92a1..c4ca1aa35 100644
--- a/examples/baremetal/stm32f103/greenblink/greenblink.qbs
+++ b/examples/baremetal/stm32f103/greenblink/greenblink.qbs
@@ -54,13 +54,42 @@ CppApplication {
     condition: {
         if (!qbs.architecture.startsWith("arm"))
             return false;
-        return qbs.toolchain.contains("keil")
+        return qbs.toolchain.contains("gcc")
+            || qbs.toolchain.contains("keil")
     }
     name: "stm32f103-greenblink"
     cpp.cLanguageVersion: "c99"
     cpp.positionIndependentCode: false
 
     //
+    // GCC-specific properties and sources.
+    //
+
+    Properties {
+        condition: qbs.toolchain.contains("gcc")
+        cpp.driverFlags: [
+            "-mcpu=cortex-m3",
+            "-specs=nosys.specs"
+        ]
+    }
+
+    Group {
+        condition: qbs.toolchain.contains("gcc")
+        name: "GCC"
+        prefix: "gcc/"
+        Group {
+            name: "Startup"
+            fileTags: ["asm"]
+            files: ["startup.s"]
+        }
+        Group {
+            name: "Linker Script"
+            fileTags: ["linkerscript"]
+            files: ["flash.ld"]
+        }
+    }
+
+    //
     // KEIL-specific properties and sources.
     //