Merge pull request #72 from umbertov/master

Support cross-compilation via `-target ...` option
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Ian A Mason 2023-08-25 06:52:55 -07:00 committed by GitHub
commit 3c946a9296
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2 changed files with 21 additions and 0 deletions

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@ -272,6 +272,23 @@ This can be done by setting the `LTO_LINKING_FLAGS` to be something like
`"-g -Wl,-plugin-opt=save-temps"` which will be appended to the flags at link time.
This will at least preserve the bitcode files, even if `get-bc` will not be able to retrieve them for you.
## Cross-compilation notes
When cross-compiling a project (i.e. you pass the `--target=` or `-target` flag to the compiler),
you'll need to set the `GLLVM_OBJCOPY` variable to either
* `llvm-objcopy` to use LLVM's objcopy, which naturally supports all targets that clang does.
* `YOUR-TARGET-TRIPLE-objcopy` to use GNU's objcopy, since `objcopy` only supports the native architecture.
Example:
```sh
# test program
echo 'int main() { return 0; }' > a.c
clang --target=aarch64-linux-gnu a.c # works
gclang --target=aarch64-linux-gnu a.c # breaks
GLLVM_OBJCOPY=llvm-objcopy gclang --target=aarch64-linux-gnu a.c # works
GLLVM_OBJCOPY=aarch64-linux-gnu-objcopy gclang --target=aarch64-linux-gnu a.c # works if you have GNU's arm64 toolchain
```
## Developer tools
Debugging usually boils down to looking in the logs, maybe adding a print statement or two.

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@ -174,6 +174,8 @@ func Parse(argList []string) ParserResult {
"--param": {1, pr.defaultBinaryCallback},
"-aux-info": {1, pr.defaultBinaryCallback},
"-target": {1, pr.compileLinkBinaryCallback},
"--version": {0, pr.compileOnlyCallback},
"-v": {0, pr.compileOnlyCallback},
@ -400,6 +402,8 @@ func Parse(argList []string) ParserResult {
{`^.+\.(o|lo|So|so|po|a|dylib|pico|nossppico)$`, flagInfo{0, pr.objectFileCallback}}, //iam: pico and nossppico are FreeBSD
{`^.+\.dylib(\.\d)+$`, flagInfo{0, pr.objectFileCallback}},
{`^.+\.(So|so)(\.\d)+$`, flagInfo{0, pr.objectFileCallback}},
{`^--target=.+$`, flagInfo{0, pr.compileLinkUnaryCallback}},
}
for len(argList) > 0 {