From 22728033308028b2401e52b1bcb72d395a9aa6e4 Mon Sep 17 00:00:00 2001 From: hkalbasi Date: Thu, 29 Jun 2023 17:28:05 +0330 Subject: [PATCH] Fix realloc problem in allocating smaller amounts --- crates/hir-ty/src/consteval/tests/intrinsics.rs | 1 + crates/hir-ty/src/mir/eval/shim.rs | 16 ++++++++++------ 2 files changed, 11 insertions(+), 6 deletions(-) diff --git a/crates/hir-ty/src/consteval/tests/intrinsics.rs b/crates/hir-ty/src/consteval/tests/intrinsics.rs index ad64a455872..bb8fca178a2 100644 --- a/crates/hir-ty/src/consteval/tests/intrinsics.rs +++ b/crates/hir-ty/src/consteval/tests/intrinsics.rs @@ -183,6 +183,7 @@ fn allocator() { *ptr = 23; *ptr2 = 32; let ptr = __rust_realloc(ptr, 4, 1, 8); + let ptr = __rust_realloc(ptr, 8, 1, 3); let ptr2 = ((ptr as usize) + 1) as *mut u8; *ptr + *ptr2 }; diff --git a/crates/hir-ty/src/mir/eval/shim.rs b/crates/hir-ty/src/mir/eval/shim.rs index cab8f267b1e..23bb4a29f87 100644 --- a/crates/hir-ty/src/mir/eval/shim.rs +++ b/crates/hir-ty/src/mir/eval/shim.rs @@ -144,14 +144,18 @@ impl Evaluator<'_> { let [ptr, old_size, align, new_size] = args else { return Err(MirEvalError::TypeError("rustc_allocator args are not provided")); }; - let ptr = Address::from_bytes(ptr.get(self)?)?; let old_size = from_bytes!(usize, old_size.get(self)?); let new_size = from_bytes!(usize, new_size.get(self)?); - let align = from_bytes!(usize, align.get(self)?); - let result = self.heap_allocate(new_size, align); - Interval { addr: result, size: old_size } - .write_from_interval(self, Interval { addr: ptr, size: old_size })?; - destination.write_from_bytes(self, &result.to_bytes())?; + if old_size >= new_size { + destination.write_from_interval(self, ptr.interval)?; + } else { + let ptr = Address::from_bytes(ptr.get(self)?)?; + let align = from_bytes!(usize, align.get(self)?); + let result = self.heap_allocate(new_size, align); + Interval { addr: result, size: old_size } + .write_from_interval(self, Interval { addr: ptr, size: old_size })?; + destination.write_from_bytes(self, &result.to_bytes())?; + } } _ => not_supported!("unknown alloc function"), }