make use of get_alloc_info

[rust.git] / src / shims / mod.rs

diff --git a/src/shims/mod.rs b/src/shims/mod.rs
index 37e7b8c40462e51a1b92d6d82ac292e698664ef3..2423ffaf5fe01f018a3cc76612608e47ae787a6a 100644 (file)
--- a/src/shims/mod.rs
+++ b/src/shims/mod.rs
@@ -1,7 +1,7 @@
-
+mod backtrace;
 pub mod foreign_items;
 pub mod intrinsics;
-pub mod posix;
+pub mod unix;
 pub mod windows;
 
 pub mod dlsym;
@@ -13,11 +13,10 @@
 
 // End module management, begin local code
 
-use std::convert::TryFrom;
-
 use log::trace;
 
 use rustc_middle::{mir, ty};
+use rustc_target::spec::abi::Abi;
 
 use crate::*;
 use helpers::check_arg_count;
@@ -27,18 +26,21 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
     fn find_mir_or_eval_fn(
         &mut self,
         instance: ty::Instance<'tcx>,
+        abi: Abi,
         args: &[OpTy<'tcx, Tag>],
-        ret: Option<(PlaceTy<'tcx, Tag>, mir::BasicBlock)>,
-        unwind: Option<mir::BasicBlock>,
-    ) -> InterpResult<'tcx, Option<&'mir mir::Body<'tcx>>> {
+        dest: &PlaceTy<'tcx, Tag>,
+        ret: Option<mir::BasicBlock>,
+        unwind: StackPopUnwind,
+    ) -> InterpResult<'tcx, Option<(&'mir mir::Body<'tcx>, ty::Instance<'tcx>)>> {
         let this = self.eval_context_mut();
-        trace!("eval_fn_call: {:#?}, {:?}", instance, ret.map(|p| *p.0));
+        trace!("eval_fn_call: {:#?}, {:?}", instance, dest);
 
         // There are some more lang items we want to hook that CTFE does not hook (yet).
         if this.tcx.lang_items().align_offset_fn() == Some(instance.def.def_id()) {
-            let &[ptr, align] = check_arg_count(args)?;
-            this.align_offset(ptr, align, ret, unwind)?;
-            return Ok(None);
+            let [ptr, align] = check_arg_count(args)?;
+            if this.align_offset(ptr, align, dest, ret, unwind)? {
+                return Ok(None);
+            }
         }
 
         // Try to see if we can do something about foreign items.
@@ -49,61 +51,53 @@ fn find_mir_or_eval_fn(
             // to run extra MIR), and Ok(Some(body)) if we found MIR to run for the
             // foreign function
             // Any needed call to `goto_block` will be performed by `emulate_foreign_item`.
-            return this.emulate_foreign_item(instance.def_id(), args, ret, unwind);
-        }
-
-        // Better error message for panics on Windows.
-        let def_id = instance.def_id();
-        if Some(def_id) == this.tcx.lang_items().begin_panic_fn() ||
-            Some(def_id) == this.tcx.lang_items().panic_impl()
-        {
-            this.check_panic_supported()?;
+            return this.emulate_foreign_item(instance.def_id(), abi, args, dest, ret, unwind);
         }
 
         // Otherwise, load the MIR.
-        Ok(Some(&*this.load_mir(instance.def, None)?))
+        Ok(Some((this.load_mir(instance.def, None)?, instance)))
     }
 
+    /// Returns `true` if the computation was performed, and `false` if we should just evaluate
+    /// the actual MIR of `align_offset`.
     fn align_offset(
         &mut self,
-        ptr_op: OpTy<'tcx, Tag>,
-        align_op: OpTy<'tcx, Tag>,
-        ret: Option<(PlaceTy<'tcx, Tag>, mir::BasicBlock)>,
-        unwind: Option<mir::BasicBlock>,
-    ) -> InterpResult<'tcx> {
+        ptr_op: &OpTy<'tcx, Tag>,
+        align_op: &OpTy<'tcx, Tag>,
+        dest: &PlaceTy<'tcx, Tag>,
+        ret: Option<mir::BasicBlock>,
+        unwind: StackPopUnwind,
+    ) -> InterpResult<'tcx, bool> {
         let this = self.eval_context_mut();
-        let (dest, ret) = ret.unwrap();
+        let ret = ret.unwrap();
+
+        if this.machine.check_alignment != AlignmentCheck::Symbolic {
+            // Just use actual implementation.
+            return Ok(false);
+        }
 
-        let req_align = this
-            .force_bits(this.read_scalar(align_op)?.not_undef()?, this.pointer_size())?;
+        let req_align = this.read_scalar(align_op)?.to_machine_usize(this)?;
 
         // Stop if the alignment is not a power of two.
         if !req_align.is_power_of_two() {
-            return this.start_panic("align_offset: align is not a power-of-two", unwind);
+            this.start_panic("align_offset: align is not a power-of-two", unwind)?;
+            return Ok(true); // nothing left to do
         }
 
-        let ptr_scalar = this.read_scalar(ptr_op)?.not_undef()?;
-
-        // Default: no result.
-        let mut result = this.machine_usize_max();
-        if let Ok(ptr) = this.force_ptr(ptr_scalar) {
+        let ptr = this.read_pointer(ptr_op)?;
+        if let Ok((alloc_id, _offset, _)) = this.ptr_try_get_alloc_id(ptr) {
             // Only do anything if we can identify the allocation this goes to.
-            let cur_align =
-                this.memory.get_size_and_align(ptr.alloc_id, AllocCheck::MaybeDead)?.1.bytes();
-            if u128::from(cur_align) >= req_align {
+            let (_size, cur_align, _kind) = this.get_alloc_info(alloc_id);
+            if cur_align.bytes() >= req_align {
                 // If the allocation alignment is at least the required alignment we use the
-                // libcore implementation.
-                // FIXME: is this correct in case of truncation?
-                result = u64::try_from(
-                    (this.force_bits(ptr_scalar, this.pointer_size())? as *const i8)
-                        .align_offset(usize::try_from(req_align).unwrap())
-                ).unwrap();
+                // real implementation.
+                return Ok(false);
             }
         }
 
-        // Return result, and jump to caller.
-        this.write_scalar(Scalar::from_machine_usize(result, this), dest)?;
+        // Return error result (usize::MAX), and jump to caller.
+        this.write_scalar(Scalar::from_machine_usize(this.machine_usize_max(), this), dest)?;
         this.go_to_block(ret);
-        Ok(())
+        Ok(true)
     }
 }