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https://github.com/carbon-language/carbon-lang.git
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Richard Smith
b138c90c9e
Remove the type canonicalization mechanism and instead rely on constant canonicalization to deduplicate types. Rename the `Canonicalize*Type` functions to reflect that they're no longer performing canonicalization. Switch code that creates types due to semantic checking, rather than due to source syntax, to directly create type constants through evaluation rather than creating an instruction and evaluating it to produce a separate constant representation. The mapping from `const (const T)` that was previously performed by type canonicalization is now implemented in expression evaluation instead. The value `<error>` is now treated as a constant value, with a special property that an instruction involving `<error>` that could possibly be constant evaluates to `<error>`. This helps avoid producing follow-on errors when an error occurs as a subexpression of an expression, such as a type, that is intended to be constant.
34 lines
1.2 KiB
Plaintext
34 lines
1.2 KiB
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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// OK, `const (const i32)` is the same type as `const i32`.
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// CHECK:STDERR: collapse.carbon:[[@LINE+3]]:25: `const` applied repeatedly to the same type has no additional effect.
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// CHECK:STDERR: fn F(p: const i32**) -> const (const i32)** {
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// CHECK:STDERR: ^~~~~~~~~~~~~~~~~
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fn F(p: const i32**) -> const (const i32)** {
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return p;
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}
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// CHECK:STDOUT: --- collapse.carbon
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// CHECK:STDOUT:
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// CHECK:STDOUT: constants {
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// CHECK:STDOUT: %.1: type = const_type i32 [template]
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// CHECK:STDOUT: %.2: type = ptr_type const i32 [template]
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// CHECK:STDOUT: %.3: type = ptr_type const i32* [template]
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// CHECK:STDOUT: }
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// CHECK:STDOUT:
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// CHECK:STDOUT: file {
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// CHECK:STDOUT: package: <namespace> = namespace package, {.F = %F} [template]
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// CHECK:STDOUT: %F: <function> = fn_decl @F [template]
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// CHECK:STDOUT: }
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// CHECK:STDOUT:
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// CHECK:STDOUT: fn @F(%p: const i32**) -> const i32** {
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// CHECK:STDOUT: !entry:
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// CHECK:STDOUT: %p.ref: const i32** = name_ref p, %p
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// CHECK:STDOUT: return %p.ref
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// CHECK:STDOUT: }
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// CHECK:STDOUT:
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