Entry point is not getting set for example programs

[tsathishkumar]

I'm trying to build blinky example with default configuration. But it seems that the entry point is not getting set by the compiler.

Output of readobj:

➜  stm32f103xx-hal git:(master) ✗ cargo readobj --example blinky  -- -file-headers
    Finished dev [unoptimized + debuginfo] target(s) in 0.09s
ELF Header:
  Magic:   7f 45 4c 46 01 01 01 00 00 00 00 00 00 00 00 00
  Class:                             ELF32
  Data:                              2's complement, little endian
  Version:                           1 (current)
  OS/ABI:                            UNIX - System V
  ABI Version:                       0x0
  Type:                              EXEC (Executable file)
  Machine:                           ARM
  Version:                           0x1
  Entry point address:               0x0
  Start of program headers:          52 (bytes into file)
  Start of section headers:          2108984 (bytes into file)
  Flags:                             0x5000200
  Size of this header:               52 (bytes)
  Size of program headers:           32 (bytes)
  Number of program headers:         3
  Size of section headers:           40 (bytes)
  Number of section headers:         16
  Section header string table index: 14

Output of size:

➜  stm32f103xx-hal git:(master) ✗ cargo size --example blinky --release -- -A
    Finished release [optimized + debuginfo] target(s) in 0.14s
blinky  :
section              size   addr
.debug_str          39258    0x0
.debug_loc           4323    0x0
.debug_abbrev        1993    0x0
.debug_info         40641    0x0
.debug_ranges        6200    0x0
.debug_macinfo          2    0x0
.debug_pubnames     11026    0x0
.debug_pubtypes     13001    0x0
.ARM.attributes        50    0x0
.debug_frame         1508    0x0
.debug_line         17848    0x0
.comment               18    0x0
Total              135868

[TeXitoi]

We need a repo to reproduce your problem.

Try this: https://github.com/TeXitoi/blue-pill-quickstart

[tsathishkumar]

The above repo is working fine. I was using the master branch before. Seems like I should have used update-for-1.30 branch from your fork. Because I see there is a difference in how we define the entry block between the branches.

[TeXitoi]

No, it depends on the version of cortex-m-rt that you are using in your Cargo.toml. The examples on this repo use 0.5, and blue-pill-quickstart use the last version 0.6.

[tsathishkumar]

Ok, so 0.5 is not working I guess. I'm going to stick with 0.6 for now. Thanks for the quick replies.

Initially I was trying to run the example that is there in this repo, master branch.

[TeXitoi]

0.5 should work. It depends on the version of cortex-m-rt that you put in your Cargo.toml. If that's 0.6 or *, then you must use #[entry] fn main() -> !, if that's 0.5 you must use entry!(main); fn main() -> !.

[tsathishkumar]

I didn't change the version of cortex-m-rt. It is 0.5.2, and the entry macro is used in the example. But it doesn't work (at least in macos).

[TeXitoi]

I can analyze this if you give a full project, but as you have something working, that may not be important.

[tsathishkumar]

I don't have a separate project. I was just trying to execute the blinky example from this repo.

cargo build --example blinky

Like you said, I currently have something working. So, not critical.