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https://github.com/carbon-language/carbon-lang.git
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Adrien Leravat
19c74ead49
Add partial support for initializing expressions for variable declaration. This is based on https://github.com/carbon-language/carbon-lang/pull/2006, which introduces expression categories, and how it is possible to convert to/from those different categories. ## Functional changes * Initializing expressions initialize directly the provided storage when used to initialize a variable. * Allows initializing expressions to avoid a copy when using `[var|let] name: type = call_expression(...)` by initializing `name` in-place. * Support `returned var: ...` and `return <expr>` * Support nested initializing expressions ## Main implementation changes * Updated PatternMatch logic to handle expression categories * Updated `VariableDefinition` interpreter statement to allocate and pass a location to initializing expressions * Update statement actions to allow passing an allocation, used by return expr or returned var * Modified the RuntimeScope API to be one step closer to the memory model we want to have * Remove `GetAllocationId` and older `Bind` which don't apply * New set of tests to highlight those different situations * Added a new intrinsic to print the allocation stack (and make sure we behave correctly, beyond visible side effects) ## Next work * Dedicated `Action` to retrieve expression category information in the interpreter (https://github.com/carbon-language/carbon-lang/pull/2927) * Avoid copies when initializing value expression from reference expression and prevent mutations for the duration of the "pinning" (https://github.com/carbon-language/carbon-lang/pull/2927) * Avoid unnecessary copies from value expression to value expression, after ensuring that even value expression temporaries are registered for destruction. * Avoid unnecessary copies when binding function arguments
15 lines
448 B
Plaintext
15 lines
448 B
Plaintext
// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
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// Exceptions. See /LICENSE for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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// AUTOUPDATE
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package ExplorerTest api;
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fn Main() -> i32 {
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var p: i32* = heap.New(5);
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heap.Delete(p);
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// CHECK:STDERR: RUNTIME ERROR: fail_use_after_free.carbon:[[@LINE+1]]: undefined behavior: access to dead or discarded value 5
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return *p;
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}
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