diff options
Diffstat (limited to 'src/runtime/symtab.go')
| -rw-r--r-- | src/runtime/symtab.go | 36 |
1 files changed, 36 insertions, 0 deletions
diff --git a/src/runtime/symtab.go b/src/runtime/symtab.go index 0d0fe8055b..f65e16ff1d 100644 --- a/src/runtime/symtab.go +++ b/src/runtime/symtab.go @@ -628,6 +628,42 @@ func moduledataverify1(datap *moduledata) { } } +// textAddr returns md.text + off, with special handling for multiple text sections. +// off is a (virtual) offset computed at internal linking time, +// before the external linker adjusts the sections' base addresses. +// +// The text, or instruction stream is generated as one large buffer. +// The off (offset) for a function is its offset within this buffer. +// If the total text size gets too large, there can be issues on platforms like ppc64 +// if the target of calls are too far for the call instruction. +// To resolve the large text issue, the text is split into multiple text sections +// to allow the linker to generate long calls when necessary. +// When this happens, the vaddr for each text section is set to its offset within the text. +// Each function's offset is compared against the section vaddrs and sizes to determine the containing section. +// Then the section relative offset is added to the section's +// relocated baseaddr to compute the function addess. +func (md *moduledata) textAddr(off uintptr) uintptr { + var res uintptr + if len(md.textsectmap) > 1 { + for i := range md.textsectmap { + sectaddr := md.textsectmap[i].vaddr + sectlen := md.textsectmap[i].length + if uintptr(off) >= sectaddr && uintptr(off) < sectaddr+sectlen { + res = md.textsectmap[i].baseaddr + uintptr(off) - uintptr(md.textsectmap[i].vaddr) + break + } + } + } else { + // single text section + res = md.text + uintptr(off) + } + if res > md.etext && GOARCH != "wasm" { // on wasm, functions do not live in the same address space as the linear memory + println("runtime: textOff", hex(off), "out of range", hex(md.text), "-", hex(md.etext)) + throw("runtime: text offset out of range") + } + return res +} + // FuncForPC returns a *Func describing the function that contains the // given program counter address, or else nil. // |