diff options
Diffstat (limited to 'compiler/symbol.go')
| -rw-r--r-- | compiler/symbol.go | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/compiler/symbol.go b/compiler/symbol.go index 89525f493..05be92f29 100644 --- a/compiler/symbol.go +++ b/compiler/symbol.go @@ -108,6 +108,28 @@ func (c *compilerContext) getFunction(fn *ssa.Function) llvm.Value { } } + // Set a number of function or parameter attributes, depending on the + // function. These functions are runtime functions that are known to have + // certain attributes that might not be inferred by the compiler. + switch info.linkName { + case "abort": + // On *nix systems, the "abort" functuion in libc is used to handle fatal panics. + // Mark it as noreturn so LLVM can optimize away code. + llvmFn.AddFunctionAttr(c.ctx.CreateEnumAttribute(llvm.AttributeKindID("noreturn"), 0)) + case "runtime.alloc": + // Tell the optimizer that runtime.alloc is an allocator, meaning that it + // returns values that are never null and never alias to an existing value. + for _, attrName := range []string{"noalias", "nonnull"} { + llvmFn.AddAttributeAtIndex(0, c.ctx.CreateEnumAttribute(llvm.AttributeKindID(attrName), 0)) + } + case "runtime.trackPointer": + // This function is necessary for tracking pointers on the stack in a + // portable way (see gc_stack_portable.go). Indicate to the optimizer + // that the only thing we'll do is read the pointer. + llvmFn.AddAttributeAtIndex(1, c.ctx.CreateEnumAttribute(llvm.AttributeKindID("nocapture"), 0)) + llvmFn.AddAttributeAtIndex(1, c.ctx.CreateEnumAttribute(llvm.AttributeKindID("readonly"), 0)) + } + // External/exported functions may not retain pointer values. // https://golang.org/cmd/cgo/#hdr-Passing_pointers if info.exported { |