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factor out the common desugaring.
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@dkm
dkm committed Jul 2, 2024
1 parent f3e83bb commit 54e06f0
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Showing 3 changed files with 54 additions and 65 deletions.
4 changes: 4 additions & 0 deletions gcc/rust/hir/rust-ast-lower-block.h
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Original file line number Diff line number Diff line change
Expand Up @@ -135,6 +135,10 @@ class ASTLoweringIfLetBlock : public ASTLoweringBase
private:
ASTLoweringIfLetBlock () : ASTLoweringBase (), translated (nullptr) {}

void desugar_iflet (AST::IfLetExpr &, HIR::Expr **, HIR::Expr **,
std::vector<HIR::MatchCase> &,
std::vector<std::unique_ptr<HIR::Pattern>> &);

HIR::MatchExpr *translated;
};

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106 changes: 45 additions & 61 deletions gcc/rust/hir/rust-ast-lower.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -25,6 +25,7 @@
#include "rust-ast-lower-pattern.h"
#include "rust-ast-lower-struct-field-expr.h"
#include "rust-expr.h"
#include "rust-hir-expr.h"

namespace Rust {
namespace HIR {
Expand Down Expand Up @@ -199,13 +200,35 @@ ASTLoweringIfBlock::visit (AST::IfExprConseqElse &expr)
std::unique_ptr<HIR::ExprWithBlock> (else_block), expr.get_locus ());
}

// Common desugaring for IfLetExpr and IfExprConseqElse
void
do_if_let_desugaring (AST::IfLetExpr &expr)
ASTLoweringIfLetBlock::desugar_iflet (
AST::IfLetExpr &expr, HIR::Expr **branch_value, HIR::Expr **kase_expr,
std::vector<HIR::MatchCase> &match_arms,
std::vector<std::unique_ptr<HIR::Pattern>> &match_arm_patterns)
{
HIR::Expr *branch_value
= ASTLoweringExpr::translate (expr.get_value_expr ());

*branch_value = ASTLoweringExpr::translate (expr.get_value_expr ());
*kase_expr = ASTLoweringExpr::translate (expr.get_if_block ());

// FIXME: if let only accepts a single pattern. Why do we have a vector of
// patterns in the IfLet?
for (auto &pattern : expr.get_patterns ())
{
HIR::Pattern *ptrn = ASTLoweringPattern::translate (*pattern);
match_arm_patterns.push_back (std::unique_ptr<HIR::Pattern> (ptrn));
}

HIR::MatchArm arm (std::move (match_arm_patterns), expr.get_locus (), nullptr,
{});

auto crate_num = mappings.get_current_crate ();
Analysis::NodeMapping mapping (crate_num, expr.get_node_id (),
mappings.get_next_hir_id (crate_num),
UNKNOWN_LOCAL_DEFID);

HIR::MatchCase kase (std::move (mapping), std::move (arm),
std::unique_ptr<HIR::Expr> (*kase_expr));
match_arms.push_back (std::move (kase));
}

void
Expand All @@ -223,46 +246,29 @@ ASTLoweringIfLetBlock::visit (AST::IfLetExpr &expr)
// _ => ()
// }

HIR::Expr *branch_value
= ASTLoweringExpr::translate (expr.get_value_expr ());
HIR::Expr *branch_value;

std::vector<HIR::MatchCase> match_arms;
HIR::Expr *kase_expr
= ASTLoweringExpr::translate (expr.get_if_block ());
HIR::Expr *kase_expr;

std::vector<std::unique_ptr<HIR::Pattern>> match_arm_patterns;

// FIXME: if let only accepts a single pattern. Why do we have a vector of
// patterns in the IfLet?
for (auto &pattern : expr.get_patterns ())
{
HIR::Pattern *ptrn = ASTLoweringPattern::translate (*pattern);
match_arm_patterns.push_back (std::unique_ptr<HIR::Pattern> (ptrn));
}

HIR::MatchArm arm (std::move (match_arm_patterns), expr.get_locus (),
nullptr,
{});
desugar_iflet (expr, &branch_value, &kase_expr, match_arms,
match_arm_patterns);

auto crate_num = mappings.get_current_crate ();
Analysis::NodeMapping mapping (crate_num, expr.get_node_id (),
mappings.get_next_hir_id (crate_num),
UNKNOWN_LOCAL_DEFID);

HIR::MatchCase kase (std::move (mapping), std::move (arm),
std::unique_ptr<HIR::Expr> (kase_expr));
match_arms.push_back (std::move (kase));

translated
= new HIR::MatchExpr (mapping, std::unique_ptr<HIR::Expr> (branch_value),
std::move (match_arms), {},
{}, expr.get_locus ());
std::move (match_arms), {}, {}, expr.get_locus ());
}

void
ASTLoweringIfLetBlock::visit (AST::IfLetExprConseqElse &expr)
{

// desugar:
// if let Some(y) = some_value {
// bar();
Expand All @@ -276,67 +282,45 @@ ASTLoweringIfLetBlock::visit (AST::IfLetExprConseqElse &expr)
// _ => {baz();}
// }
//

HIR::Expr *branch_value
= ASTLoweringExpr::translate (expr.get_value_expr ());

HIR::Expr *branch_value;
std::vector<HIR::MatchCase> match_arms;
HIR::Expr *kase_expr
= ASTLoweringExpr::translate (expr.get_if_block ());

HIR::Expr *kase_expr;
std::vector<std::unique_ptr<HIR::Pattern>> match_arm_patterns;

// FIXME: same, why do we have a vector of patterns?
for (auto &pattern : expr.get_patterns ())
{
HIR::Pattern *ptrn = ASTLoweringPattern::translate (*pattern);
match_arm_patterns.push_back (std::unique_ptr<HIR::Pattern> (ptrn));
}

// FIXME: 2 previous q? on having many patterns probably have the same answers
// as to why a single MatchArm has a vector of patterns.
HIR::MatchArm arm (std::move (match_arm_patterns), expr.get_locus (),
nullptr,
{});
desugar_iflet (expr, &branch_value, &kase_expr, match_arms,
match_arm_patterns);

auto crate_num = mappings.get_current_crate ();
Analysis::NodeMapping mapping (crate_num, expr.get_node_id (),
mappings.get_next_hir_id (crate_num),
UNKNOWN_LOCAL_DEFID);

HIR::MatchCase kase (std::move (mapping), std::move (arm),
std::unique_ptr<HIR::Expr> (kase_expr));
match_arms.push_back (std::move (kase));

std::vector<std::unique_ptr<HIR::Pattern>> match_arm_patterns_wildcard;
Analysis::NodeMapping mapping_default_2 (crate_num, expr.get_node_id (),
Analysis::NodeMapping mapping_default (crate_num, expr.get_node_id (),
mappings.get_next_hir_id (crate_num),
UNKNOWN_LOCAL_DEFID);

std::unique_ptr<HIR::WildcardPattern> wc
= std::unique_ptr<HIR::WildcardPattern> (
new HIR::WildcardPattern(mapping_default_2, expr.get_locus ()));
new HIR::WildcardPattern (mapping_default, expr.get_locus ()));

match_arm_patterns_wildcard.push_back(std::move(wc));
match_arm_patterns_wildcard.push_back (std::move (wc));

HIR::MatchArm arm_default (std::move (match_arm_patterns_wildcard), expr.get_locus (),
nullptr,
{});
HIR::MatchArm arm_default (std::move (match_arm_patterns_wildcard),
expr.get_locus (), nullptr, {});

Analysis::NodeMapping mapping_default (crate_num, expr.get_node_id (),
mappings.get_next_hir_id (crate_num),
UNKNOWN_LOCAL_DEFID);
HIR::Expr *kase_else_expr
= ASTLoweringExpr::translate (expr.get_else_block ());

HIR::MatchCase kase_else (std::move (mapping_default), std::move (arm_default),
std::unique_ptr<HIR::Expr> (kase_else_expr));
HIR::MatchCase kase_else (std::move (mapping_default),
std::move (arm_default),
std::unique_ptr<HIR::Expr> (kase_else_expr));
match_arms.push_back (std::move (kase_else));

translated
= new HIR::MatchExpr (mapping, std::unique_ptr<HIR::Expr> (branch_value),
std::move (match_arms), {},
{}, expr.get_locus ());
std::move (match_arms), {}, {}, expr.get_locus ());
}

// rust-ast-lower-struct-field-expr.h
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9 changes: 5 additions & 4 deletions gcc/rust/hir/rust-ast-lower.h
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Original file line number Diff line number Diff line change
Expand Up @@ -28,15 +28,16 @@ namespace HIR {

/* Checks whether the name of a field already exists. Returns true
and produces an error if so. */
bool struct_field_name_exists (std::vector<HIR::StructField> &fields,
HIR::StructField &new_field);
bool
struct_field_name_exists (std::vector<HIR::StructField> &fields,
HIR::StructField &new_field);

/**
* Lowers a Visibility from the AST into an HIR Visibility, desugaring it in
* the process
*/
Visibility translate_visibility (const AST::Visibility &vis);

Visibility
translate_visibility (const AST::Visibility &vis);

/**
* Main base class used for lowering AST to HIR.
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