tinygo-org/tinygo
1
0
Fork 0
mirror of https://github.com/tinygo-org/tinygo.git synced 2026-07-26 06:38:42 +00:00
Code Issues Packages Projects Releases 6 Wiki Activity

transform: refactor interrupt lowering

Browse Source 
Instead of doing everything in the interrupt lowering pass, generate
some more code in gen-device to declare interrupt handler functions and
do some work in the compiler so that interrupt lowering becomes a lot
simpler.

This has several benefits:

  - Overall code is smaller, in particular the interrupt lowering pass.
  - The code should be a bit less "magical" and instead a bit easier to
    read. In particular, instead of having a magic
    runtime.callInterruptHandler (that is fully written by the interrupt
    lowering pass), the runtime calls a generated function like
    device/sifive.InterruptHandler where this switch already exists in
    code.
  - Debug information is improved. This can be helpful during actual
    debugging but is also useful for other uses of DWARF debug
    information.

For an example on debug information improvement, this is what a
backtrace might look like before this commit:

    Breakpoint 1, 0x00000b46 in UART0_IRQHandler ()
    (gdb) bt
    #0  0x00000b46 in UART0_IRQHandler ()
    #1  <signal handler called>
    [..etc]

Notice that the debugger doesn't see the source code location where it
has stopped.

After this commit, breaking at the same line might look like this:

    Breakpoint 1, (*machine.UART).handleInterrupt (arg1=..., uart=<optimized out>) at /home/ayke/src/github.com/tinygo-org/tinygo/src/machine/machine_nrf.go:200
    200			uart.Receive(byte(nrf.UART0.RXD.Get()))
    (gdb) bt
    #0  (*machine.UART).handleInterrupt (arg1=..., uart=<optimized out>) at /home/ayke/src/github.com/tinygo-org/tinygo/src/machine/machine_nrf.go:200
    #1  UART0_IRQHandler () at /home/ayke/src/github.com/tinygo-org/tinygo/src/device/nrf/nrf51.go:176
    #2  <signal handler called>
    [..etc]

By now, the debugger sees an actual source location for UART0_IRQHandler
(in the generated file) and an inlined function.
This commit is contained in:
Ayke van Laethem
2021-11-03 01:24:25 +01:00
committed by Ron Evans
parent 30bbdd5aeb
commit edcece33ca
20 changed files with 306 additions and 402 deletions
Download Patch File Download Diff File Expand all files Collapse all files
compiler/interrupt.go
+5 -2
View File
@@ -36,6 +36,8 @@ func (b *builder) createInterruptGlobal(instr *ssa.CallCommon) (llvm.Value, erro
// Fall back to a generic error.
return llvm.Value{}, b.makeError(instr.Pos(), "interrupt function must be constant")
}
funcRawPtr, funcContext := b.decodeFuncValue(funcValue, nil)
funcPtr := llvm.ConstPtrToInt(funcRawPtr, b.uintptrType)
// Create a new global of type runtime/interrupt.handle. Globals of this
// type are lowered in the interrupt lowering pass.
@@ -47,8 +49,9 @@ func (b *builder) createInterruptGlobal(instr *ssa.CallCommon) (llvm.Value, erro
global.SetGlobalConstant(true)
global.SetUnnamedAddr(true)
initializer := llvm.ConstNull(globalLLVMType)
initializer = llvm.ConstInsertValue(initializer, funcValue, []uint32{0})
initializer = llvm.ConstInsertValue(initializer, llvm.ConstInt(b.intType, uint64(id.Int64()), true), []uint32{1, 0})
initializer = llvm.ConstInsertValue(initializer, funcContext, []uint32{0})
initializer = llvm.ConstInsertValue(initializer, funcPtr, []uint32{1})
initializer = llvm.ConstInsertValue(initializer, llvm.ConstInt(b.intType, uint64(id.Int64()), true), []uint32{2, 0})
global.SetInitializer(initializer)
// Add debug info to the interrupt global.