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Fix handling of FFI arguments - #33872

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rust-lang:masterfrom
nagisa:undef-is-llvm-for-sigsegv
May 26, 2016
Merged

Fix handling of FFI arguments#33872
bors merged 6 commits into
rust-lang:masterfrom
nagisa:undef-is-llvm-for-sigsegv

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@nagisa

@nagisanagisa commented May 25, 2016

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r? @eddyb@nikomatsakis or whoever else.

cc @alexcrichton @rust-lang/core

The strategy employed here was to essentially change code we generate from

%s = alloca%S; potentially smaller than argument, but never larger%1 = bitcast%S*%sto { i64, i64 }*
store { i64, i64 } %0, { i64, i64 }* %1, align4

to

%1 = alloca { i64, i64 } ; the copy of argument itselfstore { i64, i64 } %0, { i64, i64 }* %1, align4%s = bitcast { i64, i64 }* %1to%S*; potentially truncate by casting to a pointer of smaller type.

@nagisanagisa added the beta-nominated Nominated for backporting to the compiler in the beta channel. label May 25, 2016
@nagisa

nagisa commented May 25, 2016

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Hmm, it clashes with debuginfo.

eddyb
eddyb reviewed May 25, 2016
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Comment threadsrc/librustc_trans/base.rs Outdated

// FIXME: hacky lol?
datum::Datum::new(lltmp, arg_ty,
datum::Lvalue::new("datum::lvalue_scratch_datum"))

@eddybeddybMay 25, 2016

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This won't work with debuginfo, which wants an alloca with no casts on top.
I would suggest giving it the alloca before the cast and hope that it doesn't care about the type (debuginfo metadata should describe the actual value in the alloca all by itself).
cc @michaelwoerister

@alexcrichton

alexcrichton commented May 26, 2016

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Thanks for the quick fix @nagisa!

@alexcrichtonalexcrichton added the T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. label May 26, 2016
@nagisa
nagisaforce-pushed the undef-is-llvm-for-sigsegv branch from ae8fc5c to 0d2a84cCompareMay 26, 2016 00:26
@nagisa

nagisa commented May 26, 2016

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Added a check for debuginfo thing. All should work now.

If there’s any hard-pressing nits, feel to fork and make another PR as I’m likely to be in bed for a while now.

@eddyb

eddyb commented May 26, 2016

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@bors r+ p=100

@bors

bors commented May 26, 2016

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📌 Commit e0e50a4 has been approved by eddyb

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bors commented May 26, 2016

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⌛ Testing commit e0e50a4 with merge 73fdf78...

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bors commented May 26, 2016

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💔 Test failed - auto-linux-64-debug-opt

@eddyb

eddyb commented May 26, 2016

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Miscompiling the compiler, resulting in this for stage2 libcore:

thread 'rustc' panicked at 'RefCell<T> already borrowed', ../src/libcore/cell.rs:492

@alexcrichton Serious question: why is RUST_BACKTRACE=1 not set on the bots? I assume it has to do with some tests not taking that very well?

@alexcrichton

alexcrichton commented May 26, 2016

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No particular reason, it just hasn't been done yet. We'd probably benefit from just setting it in the build system directly.

@nagisa

nagisa commented May 26, 2016

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@bors r=eddyb 2f0da79

@nagisa

nagisa commented May 26, 2016

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@bors r=eddyb 5b40452

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bors commented May 26, 2016

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⌛ Testing commit 5b40452 with merge 3c795e0...

bors added a commit that referenced this pull request May 26, 2016
@bors
Auto merge of#33872- nagisa:undef-is-llvm-for-sigsegv, r=eddyb
3c795e0
Fix handling of FFI arguments
r? @eddyb@nikomatsakis or whoever else.
cc @alexcrichton @rust-lang/core
The strategy employed here was to essentially change code we generate from
```llvm
%s = alloca %S ; potentially smaller than argument, but never larger
%1 = bitcast %S* %s to { i64, i64 }*
store { i64, i64 } %0, { i64, i64 }* %1, align 4
```
to
```llvm
%1 = alloca { i64, i64 } ; the copy of argument itself
store { i64, i64 } %0, { i64, i64 }* %1, align 4
%s = bitcast { i64, i64 }* %1 to %S* ; potentially truncate by casting to a pointer of smaller type.
```
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bors commented May 26, 2016

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💔 Test failed - auto-win-gnu-32-opt-rustbuild

@nagisa

nagisa commented May 26, 2016

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@bors retry force

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bors commented May 26, 2016

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⚡ Previous build results for auto-linux-64-cargotest, auto-linux-cross-opt, auto-win-msvc-64-cargotest are reusable. Rebuilding only auto-linux-32-nopt-t, auto-linux-32-opt, auto-linux-32cross-opt, auto-linux-64-cross-armhf, auto-linux-64-cross-armsf, auto-linux-64-cross-freebsd, auto-linux-64-cross-netbsd, auto-linux-64-debug-opt, auto-linux-64-nopt-t, auto-linux-64-opt, auto-linux-64-opt-mir, auto-linux-64-opt-rustbuild, auto-linux-64-x-android-t, auto-linux-musl-64-opt, auto-mac-32-opt, auto-mac-64-nopt-t, auto-mac-64-opt, auto-mac-64-opt-rustbuild, auto-mac-cross-ios-opt, auto-win-gnu-32-nopt-t, auto-win-gnu-32-opt, auto-win-gnu-32-opt-rustbuild, auto-win-gnu-64-nopt-t, auto-win-gnu-64-opt, auto-win-msvc-32-cross-opt, auto-win-msvc-32-opt, auto-win-msvc-64-opt, auto-win-msvc-64-opt-mir, auto-win-msvc-64-opt-rustbuild...

@sanxiyn

sanxiyn commented May 26, 2016

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Another case of #33844.

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bors commented May 26, 2016

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☀️ Test successful - auto-linux-32-nopt-t, auto-linux-32-opt, auto-linux-32cross-opt, auto-linux-64-cargotest, auto-linux-64-cross-armhf, auto-linux-64-cross-armsf, auto-linux-64-cross-freebsd, auto-linux-64-cross-netbsd, auto-linux-64-debug-opt, auto-linux-64-nopt-t, auto-linux-64-opt, auto-linux-64-opt-mir, auto-linux-64-opt-rustbuild, auto-linux-64-x-android-t, auto-linux-cross-opt, auto-linux-musl-64-opt, auto-mac-32-opt, auto-mac-64-nopt-t, auto-mac-64-opt, auto-mac-64-opt-rustbuild, auto-mac-cross-ios-opt, auto-win-gnu-32-nopt-t, auto-win-gnu-32-opt, auto-win-gnu-32-opt-rustbuild, auto-win-gnu-64-nopt-t, auto-win-gnu-64-opt, auto-win-msvc-32-cross-opt, auto-win-msvc-32-opt, auto-win-msvc-64-cargotest, auto-win-msvc-64-opt, auto-win-msvc-64-opt-mir, auto-win-msvc-64-opt-rustbuild

@bors
bors merged commit 5b40452 into rust-lang:masterMay 26, 2016
@alexcrichtonalexcrichton added the beta-accepted Accepted for backporting to the compiler in the beta channel. label May 26, 2016
@alexcrichton

alexcrichton commented May 26, 2016

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Discussed on IRC and accepted for a beta backport

@alexcrichtonalexcrichton mentioned this pull request May 26, 2016
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This was referenced Jun 7, 2016
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@alexcrichtonalexcrichton removed the beta-nominated Nominated for backporting to the compiler in the beta channel. label Jun 20, 2016
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