2bb70812a8
This patch adds a new pragma for functions and globals to set the
section name. This can be useful to place a function or global in a
special device specific section, for example:
* Functions may be placed in RAM to make them run faster, or in flash
(if RAM is the default) to not let them take up RAM.
* DMA memory may only be placed in a special memory area.
* Some RAM may be faster than other RAM, and some globals may be
performance critical thus placing them in this special RAM area can
help.
* Some (large) global variables may need to be placed in external RAM,
which can be done by placing them in a special section.
To use it, you have to place a function or global in a special section,
for example:
//go:section .externalram
var externalRAMBuffer [1024]byte
This can then be placed in a special section of the linker script, for
example something like this:
.bss.extram (NOLOAD) : {
*(.externalram)
} > ERAM
66 строки
1,5 КиБ
Go
66 строки
1,5 КиБ
Go
package main
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import _ "unsafe"
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// Creates an external global with name extern_global.
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//go:extern extern_global
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var externGlobal [0]byte
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// Creates a
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//go:align 32
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var alignedGlobal [4]uint32
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// Test conflicting pragmas (the last one counts).
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//go:align 64
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//go:align 16
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var alignedGlobal16 [4]uint32
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// Test exported functions.
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//export extern_func
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func externFunc() {
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}
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// Define a function in a different package using go:linkname.
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//go:linkname withLinkageName1 somepkg.someFunction1
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func withLinkageName1() {
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}
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// Import a function from a different package using go:linkname.
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//go:linkname withLinkageName2 somepkg.someFunction2
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func withLinkageName2()
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// Function has an 'inline hint', similar to the inline keyword in C.
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//go:inline
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func inlineFunc() {
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}
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// Function should never be inlined, equivalent to GCC
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// __attribute__((noinline)).
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//go:noinline
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func noinlineFunc() {
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}
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// This function should have the specified section.
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//go:section .special_function_section
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func functionInSection() {
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}
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//export exportedFunctionInSection
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//go:section .special_function_section
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func exportedFunctionInSection() {
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}
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// This function should not: it's only a declaration and not a definition.
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//go:section .special_function_section
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func undefinedFunctionNotInSection()
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//go:section .special_global_section
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var globalInSection uint32
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//go:section .special_global_section
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//go:extern undefinedGlobalNotInSection
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var undefinedGlobalNotInSection uint32
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//go:align 1024
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//go:section .global_section
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var multipleGlobalPragmas uint32
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