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| author | Michael Hudson-Doyle <michael.hudson@canonical.com> | 2015-09-03 22:49:18 +1200 |
|---|---|---|
| committer | Michael Hudson-Doyle <michael.hudson@canonical.com> | 2015-09-04 05:23:28 +0000 |
| commit | eaea5ade2b5f60c6dfd72a08c9243e1651778332 (patch) | |
| tree | 0dc3e00df2e555dc22d84a336da188777b69413b /src/cmd/asm/internal/lex/input.go | |
| parent | 13e06d89c3ccba9fd4f0456d68407ff941409b57 (diff) | |
| download | go-eaea5ade2b5f60c6dfd72a08c9243e1651778332.tar.xz | |
cmd/asm: fix handling of nested #if[n]defs
The lexer needs to process all #if[n]defs, even those found when processing is
disabled by a preceding failed conditional, or the first #endif in something
like:
#ifdef <undefined>
#ifdef whatever
#endif
#endif
terminates the first #ifdef and the second causes an error. And then the
processing of the inner #ifdefs needs to ignore their argument when they are
disabled by an outer failed condition.
Change-Id: Iba259498f1e16042f5b7580b9c000bb0599733d0
Reviewed-on: https://go-review.googlesource.com/14253
Reviewed-by: Rob Pike <r@golang.org>
Diffstat (limited to 'src/cmd/asm/internal/lex/input.go')
| -rw-r--r-- | src/cmd/asm/internal/lex/input.go | 13 |
1 files changed, 9 insertions, 4 deletions
diff --git a/src/cmd/asm/internal/lex/input.go b/src/cmd/asm/internal/lex/input.go index 7e495b8edf..cd9168064d 100644 --- a/src/cmd/asm/internal/lex/input.go +++ b/src/cmd/asm/internal/lex/input.go @@ -136,10 +136,11 @@ func (in *Input) hash() bool { in.expectText("expected identifier after '#'") } if !in.enabled() { - // Can only start including again if we are at #else or #endif. + // Can only start including again if we are at #else or #endif but also + // need to keep track of nested #if[n]defs. // We let #line through because it might affect errors. switch in.Stack.Text() { - case "else", "endif", "line": + case "else", "endif", "ifdef", "ifndef", "line": // Press on. default: return false @@ -360,7 +361,9 @@ func (in *Input) collectArgument(macro *Macro) ([]Token, ScanToken) { func (in *Input) ifdef(truth bool) { name := in.macroName() in.expectNewline("#if[n]def") - if _, defined := in.macros[name]; !defined { + if !in.enabled() { + truth = false + } else if _, defined := in.macros[name]; !defined { truth = !truth } in.ifdefStack = append(in.ifdefStack, truth) @@ -372,7 +375,9 @@ func (in *Input) else_() { if len(in.ifdefStack) == 0 { in.Error("unmatched #else") } - in.ifdefStack[len(in.ifdefStack)-1] = !in.ifdefStack[len(in.ifdefStack)-1] + if len(in.ifdefStack) == 1 || in.ifdefStack[len(in.ifdefStack)-2] { + in.ifdefStack[len(in.ifdefStack)-1] = !in.ifdefStack[len(in.ifdefStack)-1] + } } // #endif processing. |